sailboat solar charge controller

Yachting Monthly

• Digital edition

Sailing with solar power: A practical guide

• Duncan Kent
• November 13, 2020

The latest solar technology makes self-sufficient cruising much more achievable. Duncan Kent gives the lowdown on everything you need to get your boat sorted

SOLAR POWER ON BOARD

Solar power is fast becoming the most popular and economic method of keeping the batteries charged on a boat.

Particularly now that the efficiency of photovoltaic (PV) panels, charge controllers and batteries is improving every day.

Furthermore, the latest technology in regulators and charge controllers has brought about a noticeable increase in useable power output, so the problems of shading and non-alignment can be compensated for more easily.

Not only has PV equipment become more efficient and cost-effective, but many of the modern devices we want to use on a boat have become less power hungry.

This means it is now far easier to provide your entire yacht’s electrical needs, both 220Vac and 12/24Vdc, from natural energy resources – particularly solar power, even if you are planning on a fully electric boat .

Thinking carefully about how much power you need and how much your boat can accommodate is key to planning a solar array. Credit: Graham Snook

WHAT DO YOU NEED?

For instance, a boat with two new, good quality, deep-cycle house batteries of 100Ah each would supply 100Ah of energy to consume between charges, if you only use the recommended 50% of available charge between each charge cycle to protect the batteries.

From this you could run:

• a modern 12Vdc fridge (approx. 1.5Ah, or 36Ah over 24hrs),
• all LED lighting (say 20Ah per day),
• various small device chargers (20Ah)
• and a number of other items such as water pumps, TVs and stereos (25Ah/day)
• Totalling around 100Ah.
• For this you’d need 400W of solar capacity.

Of course, if you like to run a lot of AC devices off-grid such as hair dryers, microwaves, toasters and the like, then you’re going to need a DC/ AC inverter, which will take you to another level in power consumption terms.

But even then, with careful planning, solar could provide a large portion of the power you need before resorting to engine charging or a generator.

THE AVAILABLE SPACE

In practical terms, a modern 40ft monohull would have the space for around 1,200W of PV panels (cockpit arch, sprayhood top, deck), maybe 1,500W with the addition of a few portable panels for use at anchor.

The 1,200W of fixed position solar array could produce around 360Ah on a sunny summer’s day (zero shading) or more likely 250Ah on the average UK summer’s day.

So that’s enough for your 100Ah general DC consumption plus another 150Ah of AC consumption via the inverter.

Of course, to do this you’ll most likely need to increase your battery capacity to around 400-500Ah for maximum flexibility (you’ll need to store as much as possible during daylight hours), a typical figure for a 40-50ft offshore cruising yacht these days.

Get your solar charging right and you may never need to hook up to shore power

Typical daily inverter loads for a cruising yacht off grid might be:

• induction cooking plate (20min) 60Ah
• microwave (15min) 30Ah
• coffee maker (20mins) 25Ah
• hair dryer (5min) 15Ah
• laptop charger (2h) 10Ah
• or around 140Ah in total.

The trick is to monitor the batteries’ state of charge (SOC) at all times and vary your use of the inverter to suit.

For example, you might want to cook supper mid-afternoon, when solar is in abundance, and then reheat it in the evening when you want to eat it.

In some cases, when you’re cruising in warm climates such as the Med, you might end up with excess charge from your solar panels .

In this situation, many long-term cruisers devise a method of ‘dumping’ the extra energy by heating water for showers.

Do bear in mind if you’re planning to live aboard full time , then it’ll be a whole different story on cloudy days and during the winter, when inverter use might need to be knocked on the head entirely.

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POWER DISCREPANCIES

There’s often confusion as to how much power you can harvest from a solar installation.

A PV panel is nearly always advertised stating its theoretical peak output power (Pw).

But in reality, on a yacht where there are limited areas in which to mount them, they will more likely produce a maximum of 60% of their peak output if mounted horizontally, increasing to 80% if tilted towards the sun and regularly adjusted.

The latter is rarely achievable on a boat, however, as even at anchor it can swing through an arc of 180° in wind or tidal shifts .

Flexible panels can be mounted on sprayhoods or awnings to add power when it’s needed at anchor or in harbour

INSTALLATION

Having trawled through hundreds of ‘deals’ to get the best price on the most efficient panels you can afford you now need to know how to install them to best fulfill your energy generation needs.

The output, even from the highest quality photo-voltaic array, will only be as good as the installation itself.

So following our guidelines should ensure you extract every last drop of energy from your investment.

PANEL MOUNTING

Sailing boats are not the ideal structure on which to mount wide, flat PV panels.

So before you go ahead and purchase what looks like the biggest and best, take a few minutes to decide on exactly where you can mount them, as this will affect what size and type of panels you should buy.

In many cases the first choice would be on an arch, davits or gantry aft, especially if you already have, or plan to fit one.

Dinghy davits, particularly on multihulls, can support a huge solar capacity

These allow a solid metal framework to be constructed that will be strong enough to take the heavier, more productive rigid PV panels.

You can also build in some form of adjuster to the framework that will allow the panels to be orientated towards the sun for the best performance.

With luck (or careful planning) a gantry will also keep them aft of the boom, thereby eliminating loss of output caused by boom shading.

The next most popular position for mounting the panels is on a cockpit sprayhood or bimini, although this will often mean using the flexible or semi-flexible panels, which are generally less efficient than the rigid ones for the same area.

ELEVATED MOUNTING

Alternatively, there are kits available for mounting panels onto lifelines, which can allow their elevation to be manually adjusted to a certain degree.

Pole-mounted panels can be used for maximum adjustability

Finally, panels can be fitted directly onto the deck by either gluing them down using mastic or attaching them onto a rigid support frame.

Once again you will probably need to use semi-flexible panels – especially if the deck surface is curved.

Rigid, glass-coated panels will obviously not be suitable for deck mounting in an area that is frequently walked over.

Don’t be tempted to drill through the panels, even along the edges, as this will invalidate the warranty and possibly damage the panel.

With solid panels, the ability to adjust the angle can add significantly to output

It might seem obvious, but the key to an efficient system is to avoid shading wherever possible.

It’s no good fitting expensive, high-efficiency PVs right under the boom as they’ll perform little better than the cheaper types.

Saying that, in good quality panels each cell will be isolated from the next by a series of diodes (one-way electrical valves), so that if one cell is shaded at least it won’t drag down the other cells within the same panel.

Older panels often didn’t have these, so the slightest partial shading caused the output of the entire panel to cease.

OVERHEATING

Another important factor that is often ignored when installing the panels is that of overheating.

If a PV panel gets too hot, which is quite likely if mounted directly onto a flat surface without an air gap behind, its output will drop quite noticeably.

To allow for some air circulation behind the panels it’s best to apply mastic adhesive in numerous large dabs.

This is best achieved by placing wooden spacer strips between the dabs until the mastic has completely cured, after which the spacers can be removed.

You might need some form of trim around one or more of the outside edges, though, if they are positioned where sheets and other lines might get caught under them.

Raising the panels up will also help water to drain off and thereby helping to avoid possible delamination from sitting in water for too long.

CHARGE CONTROL

A PV module cannot supply an electrical device directly due to the changeability of the sunlight, which in turns varies the current it can produce.

Therefore, it has to be connected to a battery, which stores and smooths its output.

Whatever the size of your solar array you will need to fit a regulator, or charge controller as they are now more commonly known, to the system in order to control the output and to help extract as much power from the panels as possible.

There are two types of PV charge controller.

The older designs, called Pulse Width Modulation (PWM) types, were fairly basic voltage regulators and simply output volts at just above battery level.

The latest controllers use Multi Power Point Tracking (MPPT) technology and can accept much higher input voltages (up to 240Vdc).

MPPT controllers can be up to 30% more efficient as they use the peak output of the panels to charge the batteries, even compensating for partial shading.

BEWARE FAKE GEAR

If you buy online do be careful to ensure you’re getting what you pay for.

There are a huge number of fake MPPTs out there, which are simply the much cheaper PWM dressed up with fake labels.

It’s hard to tell which is which, but the old adage of ‘if it looks too good to be true, it usually is’ makes good sense.

MPPT controllers are usually bigger and heavier than PWMs, but if in doubt call or email the supplier to discuss the pros and cons of their kit before buying.

If they’re not happy to chat and advise you then I would steer clear of their gear.

Some good MPPTs are made in China, but unless they have a UK supplier, I wouldn’t bother with them as you’ll have no follow-up advice.

To calculate what size controller you need simply divide the panel’s peak power in Watts (Wp) by the battery voltage, which will give you the maximum current (Amps) they could theoretically supply.

For example 240W/12V = 20A. Although it’s unlikely you’ll ever get near the peak output from any PV panel, it’s best to go for the maximum possible.

Induction cooking is now a reality on board, even without shore power

PV panels come with a short length of cable, usually around 1m long.

Some are supplied with MC4 connectors already attached but most only provide bare wires.

The latter can be easily extended using proper waterproof connections but thought must be given as to the current rating and voltage drop (usually max 3%) for the size of cable you intend to use.

If in doubt, bigger is better!

Panels can sometimes be ordered with the wiring on the back so that the cable can go straight below deck through a hole under the panel.

You may need to fit extra battery capacity if you want to run an inverter from solar charging

SERIES OR PARALLEL?

A commonly asked question is ‘should I wire my PV panels in series or in parallel?’

The simple answer is, if there’s any danger of frequent shading to one or more of the panels then install them in parallel.

If wired in series the shading of a single panel will drag down the output from all of the others in the same series.

PARALLEL IS PREFERRED

Most commonly, multiple panels are wired together in parallel to a single charge controller, with diodes protecting each panel from discharging the others should one become partially shaded.

With the advent of MPPT controllers, however, there can sometimes be a benefit to wiring two or more identical panels into a series bank, thereby presenting a higher voltage to the controller.

It’s worth noting that, like batteries, wiring PV panels in series increases the voltage only – the current capacity of the array remains the same as for a single panel.

‘Where’s the benefit of wiring them in series then?’ you might ask.

Well, the higher the voltage fed into the MPPT, the more consistent it will be with its output, which could, in some cases, prove more efficient than a parallel installation with PWM controllers.

It’s also likely to be necessary if you have a 24V domestic system.

SERIES WIRING

Series wiring is usually only done when the cable runs are long, as it helps negate the voltage drop caused by the resistance of the cable.

While a decent controller will have no problem handling the output from four or even five panels wired in series, it is often inappropriate for sailing yachts as shading just one of the panels will reduce the output of the entire series array.

If you need to do so in order to reduce cable runs then it’s best to split the panels between each side of the boat – a series bank on each side.

If you do this, then you would ideally fit a separate controller to each series PV bank and then connect their outputs together in parallel to the battery bank.

Note, however, that panels wired in series must all be the same types with an equal number of cells per panel.

Furthermore, the charge controller needs to be sized for the total of all panel voltages added together and the current rating of one individual panel.

Differently rated panels can be connected together in parallel but only if each panel has its own controller.

The outputs of the individual controllers can then be joined together to go to the battery bank.

BATTERY BANK QUESTION

Another frequently asked question is ‘Can I connect another charging source to the battery bank while the solar array is charging?’

The answer is yes.

Any decent PV controller will be protected against feedback from other charging sources.

Think carefully about where shade from mast, boom and rigging will fall. Credit: Graham Snook Photography

CABLE SIZE AND CONNECTORS

A frequent cause of reduced output from PV arrays is wiring that is too small.

The resistance of a wire conductor increases in direct proportion to its cross-sectional area, so go as big as is practicable for the least cable loss.

Each panel should be supplied with the correctly sized cables for its own maximum output.

But if you’re combining panels, either in parallel or in series, you will clearly need to rate the single feed cable to suit the maximum current available at theoretical peak solar output and to minimise voltage drop.

Likewise, the cable from the controller to the batteries should be sized to suit the controller’s maximum output current and protected with a fuse.

For outside it’s important to use exterior grade cable, which is double- insulated and UV-proof.

WEATHERPROOF CONNECTORS

And wherever possible use compatible weatherproof connectors (usually MC4) to those found on the panels rather than cutting off the plugs and hard-wiring them.

Field- assembly MC4 plugs are available, so you don’t have to drill large holes in the decks or bulkheads when feeding the cables through.

When joining more than one panel together try to use the approved multiway connectors; not only do they keep the wiring neat and tidy, but they also offer a greater contact area than budget terminal blocks.

If you have to use screw-type connectors make sure to fit proper ferrules to the wire first to avoid any stray wires in the multistrand shorting across the terminals.

When feeding a cable from above to below deck, try to go through an upright bulkhead where possible to minimise ‘pooling’ of water around the access hole.

Also, use a proper watertight deck seal that matches the cable you’re using.

If drilling through a cored deck you need to drill a larger hole first, fill it with epoxy resin and then drill the required size hole through the epoxy to ensure no water gets into the deck core.

Ideally, the charge controller should be mounted no further than 2m from the battery bank.

If you need to go further, you’ll require larger cabling to reduce the voltage drop.

A generous solar array will keep you self- sufficient indefinitely. Credit: Graham Snook Photography

CONTROLLER LOAD TERMINALS

There is often confusion over the ‘load’ output of a charge controller (often depicted by a light bulb) and what can safely be connected to these terminals.

Rarely explained in the manual, the load terminals should be pretty much ignored in a marine installation as the output on these terminals is usually very limited (10A max).

Some attach an LED light to them to indicate the controller is operating, but all your usual electrical loads should remain connected to the batteries with the battery terminals on the controller connected directly to that battery bank via a fuse.

It is possible, though, to control a high-current switching relay in certain conditions.

Parallel installation is more resilient to shading, but a series installation will increase peak charging outputs. A combination of the two offers some of the benefit of both

CIRCUIT MONITORING

Unlike most cheap PWMs, the majority of good quality MPPT charge controllers come with an alphanumeric LCD screen to let you know what is going on.

This can either be a remote display or simply one on the front of the box.

It’s obviously a lot better to have a proper numerical display than to rely on a few flashing LEDs to tell you when something’s not right.

So if your chosen controller doesn’t have one be sure to fit a battery monitor (the shunt type) into your solar circuit between the controller and the batteries.

It doesn’t have to be a very ‘smart’ monitor, just one that can display the voltage and current being supplied by the panels.

For smartphone addicts there are several wifi apps that will do the job remotely on your phone or tablet.

DEVICE PROTECTION

All good quality PV panels feature built-in diode protection between each cell to prevent a shaded cell from dragging down the productive ones.

In addition, there will be internal blocking diodes on the final output to protect the panel from polarity reversal and to ensure that the batteries can’t discharge back into the panel during the night.

The latter can be added externally, the former can’t, so check before you buy.

A fuse, rated just above the maximum current available, should be fitted between each panel and the charge controller.

Another fuse should then be installed between the charge controller’s output and the batteries.

In the case of multiple arrays, this second fuse will be rated higher than the individual panel fuses and should match the maximum current rating of the cable.

With this protection installed other charging devices can be connected in parallel at the battery, meaning the solar can be left connected even when you are hooked up to shore power and the battery charger is operating.

In some circumstances, however, this arrangement can affect the sensing of the battery by the charger, causing it to fall back into float mode.

If this becomes apparent it can be overcome by installing a manual/auto switch to disconnect the solar array when on shore power.

Check the flex of the solar panel is sufficient for your deck

EXCESS POWER DUMPING

A solar charge controller works by disconnecting the supply from the PV panels when the batteries are fully charged.

But for some full-time liveaboards in sunny climates that can be considered a waste, when the excess power could be put to good use – heating water, say.

This is commonly done using an inverter to supply AC power to the heating element.

Alternatively, you can now buy a 12Vdc element for your calorifier (hot water tank) and supply this directly from your battery bank.

Both of these methods would require a voltage sensitive relay (VSR) to disconnect the element should the battery voltage drop below a pre-set level.

Don’t expect boiling hot water, as there will probably only be enough spare power to take the chill off it before your battery bank reaches its lower threshold voltage.

A 600W/12V element will draw some 50A, from the batteries, whereas a 1kW AC element run through an inverter will need close to 100A.

A small, semi-flexible panel will be sufficient for keeping batteries trickle charged, but not for heavy use

RIGID, FLEXIBLE, OR SEMI FLEXIBLE?

Despite massive recent improvements in semi-flexible panels in recent years, the solid glass panels still offer a higher power density.

That said, they are heavier, more awkward to mount and can’t be walked on, so unless you have a dedicated gantry aft, you’re better off choosing the more rugged semi-flexibles.

Modules incorporating monocrystalline cells also have a better output than those with polycrystalline cells (that’s cells made from a single slice of silicon as opposed to layers of smaller pieces).

Output voltage also depends on the number of cells on the panel.

In the past this has commonly been 32, but now some 36 and even 40 cell panels are available.

That said, they’re larger, of course, so an array of interconnected smaller panels might be a better solution.

Module efficiency is now more often around the 20% mark, as opposed to 12-15% for older models and semi- flexible (up to 20° bend) are usually better than flexible (up to 180° bend).

A rigid panel is more efficient, but less robust

There are a huge number of panels on the market, but many use the same cells.

Sunpower Maxeon cells are exceptionally good, as are the Panasonic HIT range and LG, but they are pricey.

If the maker is offering a 25-year guarantee instead of a 3-5 year one, you can be pretty confident they’re good.

When it comes to charge controllers it’s definitely worth paying a little more for a decent MPPT.

A cheap PWM might be okay just to keep a small starter battery charged with a 30W panel, but the MPPT will give you much more when it comes to heavy service.

Victron are probably top of the range, while cheaper brands like MakeSkyBlue and EPever are also good value – but treat imports of unclear origin with care.

ABOUT THE AUTHOR

Duncan Kent has been evaluating and reviewing yachts and marine equipment for the past 30 years

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Sailboat Life

Sailboat Cruising and Lifestyle Magazine.

Sailboat Solar Systems and How-To

Solar on a sailboat goes together like hands and gloves, but sailboat solar systems can be installed in a variety of ways. The solar components themselves create an infinite combination of possibilities for off-grid sailing. Victron Energy chargers, Renogy Panels, Sunpower Yachts, BlueSea Systems, and many more brands have entered the marketplace, and that’s not including the lithium battery companies.

To simplify things, we’ve compiled three sailboat solar systems videos to give you an overview of what’s possible. And to help you decide on your own simple solar panel setup for sailing.

How-To Install Solar Panels on Your Sailboat

This system from Zingaro shows flexible panels summing 300w of power on a 38′ catamaran.

300W Solar System:

• Three 100w solar flexible panels
• 1 MPPT Solar charger controller

View on Amazon >>

100W HQST Flexible Solar Panels $100-$200

20amp Solar Charge Controller by Victron Energy $150-$200

Simple Sunpower Solar System

This simple solar system from The Fosters shows a quick and easy setup with limited space on top of a bimini.

Sunpower Solar Panels are considered by most in the industry as the gold standard. They use the highest-efficiency solar cells and have top-notch build quality. In this simple installation, three 50w panels are just enough to get you started. Plus, it’s the most affordable installation!

150w Starter Solar System

• Three 50w Flexible Solar Panels
• A Single 15amp solar charge controller

50W Sunpower Solar Panels $150-$200

75v/15amp Solar Charge Controller by Victron Energy $100-$124

Off-Grid on a DIY Solar Powered Sailboat

Here’s a special installation that turned a derelict sailboat into an off-grid sailing machine!

Simon has transformed this derelict sailboat into an epic off-grid solar-powered and fossil-fuel-free cruising catamaran. He’s been living aboard and renovating the boat for the past 3.5 years We’re excited to show you the transformation as well as how he plans to propel the boat without the use of diesel or fossil fuels!

5280w Solar System for Electric Powered Catamaran

• 16 Rigid solar panels (330w each)
• 20kwh of Lithium Batteries

240W Rigid Solar Panels $250-$300

200AH Lithium 4d Battery $1200-$1200

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Sizing and selecting solar controllers for Boats

Sep 18, 2020 | Tech Blog | 12 comments

by Tom Whitehead

With the rising awareness of energy use and conservation, and the expanding demand for power on both day-use recreational and offshore cruising boats, many boat builders and boat owners are turning to alternative sources of power, including solar.  The development of lightweight, marine grade solar panels that can be mounted on canvas, or fully integrated into the decks has made this technology more available to all.  The choice of what panels to install is often straightforward and decided by their size and where/how they can be mounted.  The decision of how to wire the system and choose the best type and number of controllers is more complicated, and is influenced by several factors including – shading and panel configuration; panel voltage, current and wire runs; buck vs. boost controllers; battery type and voltage; temperature sensing capabilities and methods. You need to consider all the variants of the system to make the best choice for a controller.

The sophistication and efficiency of solar controllers has improved greatly in recent years. The MPPT (Maximum Power Point Tracking) controllers have essentially eclipsed the older PWM (Pulse Width Modulation) versions, offering much greater efficiency at harvesting power from the sun.

A quick summary of the differences between PWM and MPPT

The earlier designs of solar panels were made from smaller cells and cut cells put in series, resulting in  voltages that were often higher than was safe for applying directly to a battery for charging.  The PWM (Pulse Width Modulation) solar controllers were developed to keep voltage at a safe charging level.  These controllers feed the power straight to the battery until it reaches a predetermined acceptance level. They then keep the voltage constant and safe by ‘pulsing’ the panel voltage on and off, but this results in significant losses in actual charging current to the battery.

The MPPT (Maximum Power Point Tracking) controllers register the optimal combination of amps and volts in any set of conditions, and then track this ‘power point’ as conditions of light intensity and air temperature change. The DC (direct current) panel output is inverted to high frequency AC (alternating current) and then converted back to DC to charge the battery. The result of this inversion/conversion process is that more amps can be delivered to the battery than were produced by the panel. These controllers are also more efficient in low light angles and soft shading conditions.

This article will focus only on MPPT controllers.

Defining electrical terms for Solar Panels 

We will assume the panels have already been chosen. What information do you need about the panels to help you choose the appropriate controller?  All panels are given ratings under Standard Test Conditions (STC). The STC are:  1000 watts per square meter (W/m2) of irradiance; a cell temperature of 25C(77F); and an air mass coefficient of (AM) 1.5.  This is a combination of ideal conditions that will rarely occur, but nevertheless it enables important information to be provided so that cables and fuses can be sized safely.  Depending on the type and number of cells in the panel (cut cell, polycrystalline, monocrystalline), each will put out different amounts of voltage and current (amperage) in varying conditions.

Each rating is defined here:

• Max Power Voltage-Vmp (V) – This is the voltage that occurs when the module is connected to a load and is operating at its peak performance output under standard test conditions (STC). This is determined by the number of cells in series, their basic voltage and the temperature of the cells.
• Max Power Current – Imp (A) – Maximum current the panel will produce when under load. This is dependent on the size, type and quality of the cells, and the strength and quality of the available sunlight.
• Watts – The rated power of a panel under STC. This power rating is equal to the Vmp (max power voltage) X Imp (max power amps). For example, the SP 104 has a Vmp of 18.22v X Imp of 5.71a = 104 watts
• Open Circuit Voltage-Voc (V) – Maximum voltage the panel produces when not connected to a load. Use Voc when calculating voltage limits for series set ups, as this is the maximum possible voltage the panel can put out – even if only for a moment.
• Short Circuit Current Isc (A) – This is the current through a solar cell when the voltage across the solar cell is zero (i.e., when the solar cell is short circuited). Panels built with the same type of cell, will all have the same Isc or short circuit current.

Shading and Panel Wiring Choices

Effects of shading 

Solar panels perform best in bright sunlight at solar noon with little or no shading.  Most boats, either sail or power, will create some type of shade for a solar installation unless the panels are on the very top of a fly-bridge, or extremely far aft on a set of davits or a bimini.

Soft Shading, essentially shadows, will reduce the output of an individual cell if it is completely covered.  Because solar panels are made up of strings of individual cells wired in series, the shaded cell or cells consume power from the non-shaded cells in the series string. Most panels have bypass diodes built into the panels to help alleviate the problem, but often the panel output is reduced by half.

Hard Shading , or when a totally opaque object covers a cell, greatly increases the losses. A hard shadow “…has the effect of knocking out a percentage of the panel’s output equal to the percentage shading of a single cell. ” (Calder, Professional Boatbuilder, #182) Hard shading can also cause the other cells in a string to back feed the covered cell, creating a hot spot, and possibly a fire, so never leave boat cushions or other similar objects on a solar panel!

Some cells are small or cut, and others larger.  The panels made up of smaller cells do poorer in shade, as it is easier to completely cover the individual cells.  Larger, 5 – 6” mono cells are harder to completely cover and therefore do better with soft shading.

Panel Wiring Configurations

Solar panels can be wired three different ways – Isolated, in Series or in Parallel.

Isolated – By far, the best way to manage potential shading of panels is to give each panel its own, individual solar controller.  If a cell on one of the panels is shaded, it only effects the output of that panel, while the other panels continue to function independently.  The drawback to this is the number of wires and controllers to install and manage.

Series – By putting panels in series you essentially create one large panel and this allows you to run a single set of wires down below to a single, larger controller.  This is only recommended when the risk of shading is nonexistent or very low, and wire runs need to be minimized. Only panels with identical cells of equal amperage can be put in series.   Remember the result of putting panels in series is that the voltage of each panel is added together, but the amperage stays the same. This information is important when choosing a controller. For example: Three SR 160 watt panels in series each have a Vmp of 18.6v, but a Voc of 23v.  If they are put in series, the controller needs to be rated for at least 23v x 3 = 69v, not 3 x 18.6 = 55.8v. Also, the total wattage is now 480 watts. However, the Imp 8.6a and the Isc 9a, stays the same. The downside of large series systems is the high DC voltage. Even though the wires size can be relatively small, some builders and boat owners are not comfortable with 60 – 80 volts, DC running through the boat.

Parallel – Panels are sometimes wired in parallel to avoid increasing voltage and to minimize wire runs.  In this situation, blocking diodes must be installed between the panels to prevent a higher producing (non-shaded) panel from back feeding a lower producing (shaded) one.  These blocking diodes also create a voltage drop of approximately 0.7v.  Only identical panels with the same voltage should be put in parallel. The result of paralleling panels is that the voltage stays the same, but the amperage is multiplied.  For example, using the same three SR 160 panels mentioned above, The Vmp and Voc would stay the same but the amperage would be three times that of a single panel, or Imp 8.6a X 3 = 25.8a, total Imp.  This higher amperage creates the need for larger cables to run from the panels to the controllers, and if the run is long, it could be a deterrent to this type of configuration.

Panel Voltage and Current

Buck vs. Boost

As noted above the total voltage and current ratings of panels combined in either series or parallel or even series/parallel combinations vary based on the wiring configuration. All solar controllers are rated to handle differing amounts of voltage, amperage and total watts.  Most controllers bring voltage down to the acceptable charge level (Buck controller), but some raise voltage up (Boost controller).

With the advent of mono crystalline panels, using large cells in small configurations, it is now more common to have a panel that produces less than 12v, but with greater amounts of current.  In fact, most of the more popular panel sizes under 100 watts produce less than the required charging voltage of a 12v battery (13.8v – 14.4v volts). Therefore, it is important to determine whether the output voltage of the panel (or panels) will be greater or less than battery voltage.  If the max power voltage (VMP) is equal to or less than battery voltage, you need a boost controller.  If the voltage is greater than battery voltage, you need a buck controller. At this time, only Genasun and Western make boost controllers. (Western also makes a versatile controller, the WM 10, that will do either buck or boost.) If the panel voltage is over the battery charge voltage of 14.4v, you need a buck controller.

Total Voltage & Watts

Once you have determined whether you need a ‘buck’ or ‘boost’ controller, you next need to compare the total wattage, voltage and amperage ratings of the panel or panels with the ratings of the controller.  For example:  The SR+78 watt panel at 9.6v Vmp requires a boost controller and the Genasun GVB-8-12-Pb has a max panel power rating of 105w. 78 watts is well within the 105 watt rating so you are good to go. The Voc of this panel is only 11.7v, and the controller is rated up to 63v. Finally, if the panel is operating at its maximum power (Vmp) at 9.6v it would be producing 8.1a. The max input current of the GV-B is rated at 8a, but we know from the manufacturer that max current up to 9a is fine.

Now let’s look at a ‘buck’ controller situation. The chosen panel is an SR+ 175 watt, with a Vmp of 21.6v.  A Genasun GV-10 has a limit for max panel voltage (Vmp)  of 34v, so it looks promising; but the rated watts limit is only 140w, and max output current is only 10.5a,  so we need to move to a larger controller such as the Victron 75/15 which has a rating of 200 watts, max panel Voc of 75v and a max output current of 15a. One point of confusion is the difference between the rated current out put of the panel, and the max current output of the controller.  Remembering that the MPPT controllers can actually produce more current than the panel itself. In this case, the SR+ 175 has a Vmp of 21.6v. Since Amps = Watts/Volts — 175/21.6 = 8.1a. So one might think that this panel is OK for the GV 10 since the Voc is fine and it outputs 8.1a.  However, the controller is rated for Max Power Output, and If you divide 175 watts by the battery voltage of 12v you get 14.5a. This output current exceeds the 10.5a rating of the controller.  It is always important to check the total wattage rating of the controller, as this usually will guide you correctly.

When putting panels either in series or parallel, remember to not only add the wattage, but check the total Voc of the panels when in series, and the total Imp of the panels when in parallel.  Suppose we decide to put four SR 108 panels in series on the top of a flybridge where there is no shading. Total wattage – 432w; total Voc – 61.2v; panel output current is 8.6a; but maximum current to a 12v battery bank is (432/12= 36a .) You might think the Victron 100/30 would work as the wattage rating is 440w, the max panel Voc is 100v, BUT- the max output current is only 30a, slightly less than the 36a you need.  Most panels will never quite reach their peak performance, so the 30a might be close enough, but to be safe you need to move up to the 100/50 with the 50a rating.

Putting those same panels in parallel, the total wattage is still 432w, the Voc is now only 15.3v, but the panel current is now 34.4a. (The panel current has a direct effect on the wire size running from the panels to the controller, and for this parallel set up this wire will need to be a much larger diameter, depending on the distance there and back.) The wattage of the parallel set up should still be the primary guide, but again, the power output to a 12v battery system is larger than 30 amps, so always check the max output amps of the controller as well.

Minimum panel voltage

Controllers have a minimum voltage to turn on. This important rating is often overlooked.  With the advent of monocrystalline, lower voltage panels, it is important to check for all buck controllers to ensure the panel V is high enough.  Even boost controllers have a minimum amount of voltage needed to turn on, so check the fine print! A GV-10 requires 2V over battery voltage (14v) to function; the Blue Sky only needs 0.2v over battery voltage; the Western requires 2.5v over battery voltage and the Victron needs 5v over battery voltage.

Battery Voltage & Type

Not all battery systems are 12v! Many larger boats are moving to 24v systems, and for electric propulsion, there is a wide range of voltages from 36v, 48v and on up.  Make sure of the voltage of the battery bank that you are going to charge.

Battery Type

The days of flooded lead acid being the only battery type on a boat are long gone. The various types of lead batteries can include – Flooded, Gel, AGM (several variations), TPPL(thin plate, pure lead), Carbon Foam (Firefly), Lead Crystal, etc.,etc. Then there are the increasing Lithium-ion based chemistries.

All of these various types and manufacturers can require different charge parameters. When picking a solar controller for a specific battery type, make sure of what the charge parameters are, and if the stock settings do not suit your battery bank, you will need to find a controller that is fully programmable for the specific needs of your battery chemistry and construction.

Location/Temperature Compensation

Most solar controllers use a form of temperature compensation to moderate the target charge voltages based on battery temperature.  A cold battery can be safely charged at a significantly higher voltage than a warm battery.  Most published charging voltages are for a standard temp of 77 F.  The various controllers get temperature information in different ways.  Some, like the Genasun and original Victron use internal temperature sensing.  This means that they need to be positioned within 12” of the batteries to sense the ambient temperature, or at least be in a compartment that has the same temperature as the battery compartment. Others like the Blue Sky and the Western use a wire that runs from the battery post to the controller.  The newer, “Smart” Victron controllers now use Bluetooth to both send and receive temp and voltage information. They also allow you to view their performance with an app that you can download to your smartphone, tablet or laptop computer.  The simpler controllers either have LED indicator lights to let you know what they are doing or a small readout screen.  What ever controller you choose, it is important to decide where it will be located for viewing or not, and how it gathers the temperature information it needs.

When installing solar panels, you need to estimate the amount of shading. This determines how multiple panels will be wired – either isolated, in series or in parallel. This defines the system voltage and whether you need a buck or a boost controller.  The panel configuration determines the total wattage, voltage and power output that need to be matched to the controller’s ratings. You also need to consider the battery voltage and the type of battery chemistry and charge parameters. Finally, remember the need for temperature compensation, and if/how the controller needs to be read or monitored.

12 Comments

Great article and very helpful. One question I often see is when connecting multiple controllers to a battery bank for example in an isolated configuration. Each controller has a battery sense feature of some sort. How does one deal with a situation where one controller is sensing the voltage output of another controller? Battery sense is what determines output in a controller so if one controller is in bulk charge mode could not another controller be fooled into reducing its potential output?

Good question. The controllers feed the battery with current to raise the voltage up to the various targets. (example: Bulk/Absorp 14.4v, Float 13.4v) Since all the separate controllers are measuring the voltage of the battery, they will react the same. The controllers should all be set to the same target voltages, and should function the same throughout the day. When the battery reaches 14.4v, all controllers will move to absorption if there is no voltage drop in the cable; when the absorption period is done the controllers will then hold the battery at 13.4v for the duration of the float.

Based on the photo – you have nine solar feeds coming in. What is the best cable gland or other pathway to get the solar panel cables into the boat without tuning the deck into swiss cheese or cable gland acne?

This is a valid question, and a lot depends on the layout of the panels and whether they are run through the deck with backside wiring, or through a variety of deck glands. There are now glands that hold up to six wires in an oblong shape that can be used. In some cases, the panels can either be put in series or parallel to reduce the number of controllers and wires that need to go through the deck.

Sooo for a single G31 Carbon Foam Firefly system running DC refrigeration compressor and occasional bumps of a water pump, LED lighting modest electronics charging, that is occasionally being charged from an alternator, getting boosted and maintained by a converter charger , and kept steady by a solar feed, which is better controller an MPPT or PWM

Whatever the situation, the MPPT controller is always superior. It will harvest more power from the panel and with great efficiency.

Great article. Thank you. I see a breaker for an on/ off switch. The breaker has a Battery side and an Aux side. Does one connect the breaker to the fuse box with the post marked Batt since that is direction the current is coming from?

Hi Thomas, You can use either side of the breaker. It is simply “in line” between the parallel outputs of the controllers and the battery. It can function in either direction. It should be mounted within 7” of the battery, since it is there to protect the wire between the battery and the solar controllers.

Fantastic information. it has helped me a lot. If I may ask. I am installing two 455 wat panels on my fully enclosed flybridge and I will have two MPPT Controllers. Where would be the best place to locate the controllers x two. The engine room is about 5.5mtr away from the panels and it gets rather hot in there. The batteries are also located there. I have what appears to me to be the ideal spot under one of the seats in the flybridge, which is well ventilated and dry. Your thoughts would be much appreciated. Regards Steve

Hi Steve – If you are using a controller like the Victron MPPT that uses a remote Bluetooth sensor to monitor voltage and temperature, you can mount the controllers anywhere on the boat between the output of the panels and the batteries or charge bus. Since the controllers sometimes shed heat, it is NOT a good idea to put them into a hot environment, UNLESS that is the only way that they gather the temp information they need to do temp compensation during charging. Generally, it is a bad idea to have batteries in the engine compartment, as every degree above 72deg. F that a battery must live in takes cycles away from their lifespan. Make sure that the controllers you use have a temperature compensation feature and that they can accurately measure the battery temp.

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What You Need To Know About Boat Solar Panels

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Sunshine and boats are a natural together, so why not use all that free energy? Here’s the lowdown on solar panel selection and installation

I first embraced the idea of solar power while up a pole (literally) in the Atlantic Intracoastal Waterway replacing dead batteries. It was the early 1980s, and I was maintaining buoys, beacons, and other such Aids To Navigation (ATON) for the U.S. Coast Guard, replacing massive, nonrechargeable batteries with rechargeable solar-powered ones. The higher-ups said the solar rechargeables would last six years – twice as long as the one-shot batteries. As the deck-ape in charge of lugging all those batteries up and down the ladders, my back and I immediately appreciated the whole “free power from the sun” thing, a concept I continue to embrace.

The strategy behind s olar energy onboard is simple: A solar panel converts sunlight into electricity, after which wiring conducts it to your batteries for storage until needed. Solar panels are used to keep batteries or banks charged rather than to power equipment directly. This arrangement allows the panels to store generated power whenever produced, while providing a steady source of power to a piece of equipment even when the panel is producing no power.

While they do require an initial outlay, solar panels can easily pay for themselves in money saved and independence gained over their service life. They’re noiseless, have no moving parts, and they provide free electricity for years with minimal maintenance. Solar panels also have the benefit of being modular, letting you start small and add more as your power requirements increase.

The benefits of solar

Almost any boat can benefit from solar power. Whether at a slip, mooring, or on a trailer, boats can keep their batteries topped off without the need for external power. You can also use solar power to supplement or even replace other onboard charging sources, reducing or eliminating the need to run engines or generators to keep batteries topped off (a wasteful practice that burns fuel while wearing down the costliest pieces of equipment onboard).

While underway, it’s a plus to be able to recharge a dead battery in an emergency – say, to operate a VHF radio or navigation gear. While dockside, solar panels keep batteries charged and vital systems (such as bilge pumps) up and running without the need for shore power.

Just about any boat can benefit from solar power, whether it’s to keep batteries topped off or supplement other onboard charging sources.

Mount solar panels where they are exposed to maximum sunlight but do not interfere with operation of the vessel. 

Bottom: Something as simple as the shadow of a line or shroud can reduce or halt output.

Types of panels

Solar panels contain photovoltaic cells – small silicon semiconductor devices that convert sunlight into electricity. Each cell generates between 0.45 and 0.5 volts, depending on exposure to direct sunlight. Cell size determines amperage, with a 3-inch cell producing roughly 2 amps, a 4-inch cell a little over 3 amps, and a 5-inch cell around 5 amps.

Construction-wise, the three main types of solar panels are monocrystalline, polycrystalline, and amorphous (or thin-film) technology.

Monocrystalline panels have been around the longest and remain the most popular. The panels are constructed of thin slices of crystal silicon (each cell is cut from a single crystal) housed in a rigid, aluminum frame and covered with tempered shatterproof glass. The panels have a uniform black, blue, or gray appearance and are generally quite rugged, although they can be cracked or broken if subjected to extreme abuse.

Monocrystalline panels have the longest service life of the three types. With a conversion efficiency of around 17%, they’re also the most efficient and have the highest electrical output per area, but they are also the most expensive.

Polycrystalline cells are sliced from a cast silicon block and have a shattered glass appearance. Built in much the same way as monocrystalline panels, they’re rectangular, giving the panel itself a tiled look. Their life span is similar to monocrystalline panels, and while their conversion efficiency is lower (by 14%), they’re also a bit less expensive.

Amorphous panels are made by placing a thin film of active silicon on a solid or flexible backing (such as stainless or aluminum sheeting) depending on whether the panel is to be rigid-framed and glass-fronted or flexible. Flexible amorphous panels, in which cells are sandwiched between rubber and polymer covers, are light and tough enough that you can walk on them and, in some cases, even roll them up for storage.

This type of solar panel is also better if shade is an issue. With crystalline panels, even the thin shadow of a rope or shroud across one cell can reduce or halt output of an entire module. Amorphous panels have “bypass” diodes that essentially turn off shaded cells and provide a current path around them. Some monocrystalline panels also have bypass diodes, but this feature comes at an increase in cost.

Amorphous panels are the least expensive of the three types, but their efficiency is also lower – around 8%, or roughly half that of a monocrystalline type. This lower output is somewhat mitigated in newer panels, however, which use three-layer construction. Each layer absorbs different colors of the solar spectrum, so the panel will deliver more power longer each day and during lower light conditions than the other two types.

The charge controller should be mounted below decks and as close to the battery as possible. 

Follow manufacturer instructions for wire connections.

Planning the system

While factors such as cost, mounting options, and output are important, a successful installation depends on knowing what you want the system to accomplish. Is the goal to float-charge a single battery or supplement an overall vessel energy plan? Answering these questions up front will help determine the type, size, and number of panels required.

To understand the process better, let’s walk through the basic steps to determine power requirements and installation considerations for a single solar panel installation. While the example itself is simple, the steps are the same used to plan more complicated installations.

For our example, the goal is to install a solar panel to provide charging for a single 12-volt, 100-amp-hour wet-cell battery used to power an automatic anchor light on a moored vessel.

The first step is compiling a daily power consumption estimate to determine how much solar power is needed.

The daily self-discharge rate for a wet-cell battery is roughly 1%, meaning our 100-amp-hour battery requires one amp every 24 hours just to maintain the status quo. The anchor light draws 50 milliamps per hour of operation, and we’ll assume it operates 10 hours each night. Multiplying current draw (50 milliamps) by hours of daily operation (10) generates a daily energy expense of 500 milliamps or .5 amps.

This means our solar panel must meet a minimum daily energy tab of 1.5 amps – one amp of battery self-discharge rate plus .5 amps of power draw for the anchor light.

Next up is figuring out panel size and the best mounting location. For our example, let’s assume the panel will be a horizontal, fixed-mount installation. A 10-watt horizontally mounted panel should generate between 3- and 5-amp hours per day.

We’ll need at least 13 volts to fully charge our 12-volt battery. As most solar cells generate at least 0.45 volts, you’ll want a panel with a minimum of 33 cells, which should provide around 14.85 volts.

Keep in mind that’s the minimum needed, which may not be enough once you factor in a few cloudy days. Most panels are designed to generate between 15 and 20 volts to overcome problems like cloudy days or inherent electrical resistance within the panel or installation components. While this higher voltage lets you make up for less electrically productive days, it also means you’ll want to install a solar charge controller (voltage regulator) to avoid battery damage due to overcharging.

Attempts to plan a system that tries to use the output of the panel and capacity of the battery to prevent overcharging (and avoid the installation of a charge controller) is false economy and should not be done. The system will never meet its full output potential and, worst case, can damage the battery due to overcharging.

A word on ‘charge controller confliction’

If your vessel has multiple charging sources, such as solar panels and a wind turbine, a crucial but often overlooked consideration is “charge controller confliction.” In short, this is an issue where the charge controller for your solar panel and the charge controller for your wind turbine are internally adjusted to the same maximum charge voltage set point. This means they are constantly fighting each other to be the dominant power source, which results in diminished overall charging output and performance. An in-depth article on this issue can be found at ­missioncriticalenergy.com (in the website footer, click “Superwind Turbine Manuals & Technical Bulletins.” Under the header “Charge Controllers,” select the document “Resolving Charge Controller Confliction”).

While this article addresses charge controller confliction at remote, off-grid sites, the information provided is also applicable to vessel installations. — F.L.

Location and mounting

Solar panels should be mounted in a location where they are exposed to the maximum amount of sunlight but do not interfere with operation of the vessel or the movement of passengers and crew. Solar panels will typically be either fixed or mounted on some type of movable bracket that allows you to actively point the panel toward the sun for maximum output. Both methods have their pros and cons. Fixed panels (which are normally mounted horizontally) don’t produce as much power as a panel that can be adjusted to face the sun. The downside is that adjustable panels must be aimed throughout the day to maximize their output.

Use good quality, marine-grade heat shrink connectors (top) and liquid electrical tape (right) to create airtight, waterproof seals and reduce corrosion.

Installation

After choosing and mounting your panel, it’s time to connect it. The first thing you need to determine is the size (gauge) of the wiring to be used. Multiply your panel’s rated amp output by 1.25 (which adds a 25% safety factor). Then measure the length of the entire wiring run, panel to battery, and multiply by 2. Once you have these two numbers, refer to the American Boat and Yacht Council’s (ABYC) 3% voltage-drop table for wire size. Ancor Products offers a handy wire calculator on its website ( ancorproducts.com/resources ).

Always use good quality marine grade connectors  and tinned, multi-stranded copper wire with vinyl sheathing. The wire will run from the solar panel to the charge controller first, then to the battery. Try to keep the wire run as short as possible, and if it transits an external deck or cabin house (it likely will), be sure to use an appropriate weatherproof deck fitting.

The charge controller should be mounted below decks and as close to the battery as possible. You’ll always want to follow the manufacturer’s instructions for connections, but in a typical installation you’ll connect the solar panel’s positive (red wire) lead to the charge controller’s positive input wire or terminal and the negative (black wire) lead to the charge controller’s negative input wire or terminal.

Next, connect the charge controller’s negative output to the battery negative terminal and the controller’s positive output to the battery’s positive terminal via an appropriately sized in-line fuse (or circuit breaker). ABYC recommends these be installed within 7 inches of connection to the battery or other point in the DC system. To reiterate, the installation of the charge controller can vary among models, so follow the manufacturer’s installation instructions.

Finally, ensure all connections are waterproof and secure any loose wire runs with wire ties and cable clamps for a neat installation. Then get ready to lean back and soak up some free sun.

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Frank Lanier

Contributing Editor, BoatUS Magazine

Capt. Frank Lanier is a SAMS Accredited Marine Surveyor with more than 40 years of experience in the marine and diving industries. He’s also an author, public speaker, and multiple award-winning journalist whose articles on boat maintenance, repair, and seamanship appear regularly in numerous marine publications worldwide. He can be reached via his YouTube channel “Everything Boats with Capt. Frank Lanier” and website captfklanier.com.

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Adding Solar Power to a Sailboat

• By Emily Fagan
• Updated: October 18, 2019

During our nearly four-year cruise of Mexico, my husband, Mark, and I lived almost exclusively on 555 watts of solar power charging a 640-amp-hour house battery bank. We anchored out virtually every night aboard our 2008 Hunter 44DS, Groovy , and relied on the sun for power. During one 10-week stretch, while we waited for a replacement engine alternator to arrive, our boat’s solar panels were our sole source of power. We had no backup charging system to turn to, and yet we lived and sailed comfortably the entire time. Mounting solar panels on a sailboat was not difficult, but a few key decisions made a huge difference in how effective our panels were.

A solar-power installation on a sailboat is made up of two independent systems: one system to charge the batteries, and another system to provide 120-volt AC power for household appliances. In the charging system, the solar panels convert sunlight into electrical current and deliver it to the batteries via a solar charge controller. Similar to a voltage regulator, the charge controller acts as a gatekeeper to protect the batteries from receiving more current than they need as they are being charged. In the AC power system, an inverter or inverter/charger converts the 12-volt DC power in the battery into 120 volts AC whenever it is turned on.

Panel Positioning and Wiring Considerations

One of the biggest challenges for sailors installing solar power on a sailboat is finding a place on the boat where the panels will be shaded as little as possible. Just a few square inches of shade on one panel can render that panel all but inoperable. Unfortunately, between the mast, radome, spreaders and boom, shadows cross the deck all day long, especially as the boat swings back and forth at anchor.

What’s worse, if the panels are wired in series rather than in parallel, this little bit of shade can shut down the entire solar-panel array. When we installed solar power on Groovy , we had already lived exclusively on solar power in an RV for over two years. Our RV solar panels had been wired in series, and we had witnessed the array shutting down current production when just half of one panel was shaded.

Choosing whether to wire the panels in series or parallel on a boat affects the wire gauge required, which is why many solar-power installers lean toward wiring the panels in series. Panels wired in series can be wired all the way to the solar charge controller with a thinner-gauge wire than those wired in parallel. This is because the voltage of panels wired in series is additive, while the current remains constant, so the current flowing is just that of a single panel. In contrast, the current flowing from panels that are wired in parallel is additive, while the voltage across them is not. This means that in a parallel installation, the current going to the charge controller is several times higher and requires much thicker cable to avoid any voltage loss over the length of the wire.

Not only is thinner-gauge wire less expensive, but it is also more supple and easier to work with, making the job of snaking it in and around various crevices in the boat and connecting it to the solar charge controller much less of a struggle. Thus the choice between series and parallel wiring boils down to a trade-off between system performance, expense and ease of solar system installation.

Luckily, the size of the wire can be reduced if higher-­voltage solar panels are chosen. Since watts are determined by multiplying volts by amps, a higher-voltage panel that generates the same watts as a lower-voltage panel will produce less current. Therefore, selecting nominal 24-volt panels instead of 12-volt panels allows for the use of thinner wire sizes no matter how they are wired.

Our Marine Solar Panel Design Choices

In our installation, we decided to mount three 185-watt, 24-volt (nominal) Kyocera solar panels high above the cockpit, well aft of the boom, as far away as possible from potential shade. Our Hunter came with a big, solid stainless-steel arch, and we turned to Alejandro Ulloa, a brilliant metal fabricator at Baja Naval Boatyard in Ensenada, Mexico, to build a polished stainless-steel solar-panel arch extension onto the existing structure. He designed the arch extension with integrated telescoping davits to hoist our dinghy as well as support the solar panels. These davits were strong enough — and the lines and blocks had enough purchase — that either of us could lift our light Porta-Bote dinghy with its 6-horsepower outboard without a winch.

We spaced the panels about a half-inch apart and wired them in parallel. Using two twin-lead wires, we snaked the three positive leads and one common ground down through the inside of the arch tubes so they wouldn’t be visible, and placed wire loom over the exposed wires under the panels.

The junction points for the three parallel panels were on positive and negative bus bars inside a combiner box, all mounted in a cockpit lazarette. Inside the combiner box, we installed three breakers, one for each panel. This gave us the ability to shut off any or all of the panels if we needed to (we never did).

We mounted a Xantrex solar charge controller (model XW MPPT 60-150) in a hanging locker, as close to the batteries as possible, in a spot where it was easy to monitor and program. We ran twin-lead wire from the combiner box to the charge controller and from there to the batteries.

Our boat came with three new 12-volt Mastervolt 4D AGM house batteries, all wired in parallel, for a total of 480 amp-hours of capacity. We wanted a bigger house battery bank, and because it is best for the age, type and size of the batteries to be matched, we added a fourth new Mastervolt 4D AGM house battery, which brought our total to 640 amp-hours. Our batteries were installed at the lowest point in the hull, below the floorboards, and they ran the length of the saloon, from just forward of the companionway stairs to just aft of the V-berth stateroom door.

The best way to charge a bank of batteries that are wired in parallel is to span the entire battery bank with the leads coming from the charge controller. We did this by connecting the positive lead from the charge controller to the positive terminal of the first battery in the bank, and the negative lead from the charge controller to the negative terminal of the last battery. By spanning the entire bank, the batteries were charged equally rather than having the charging current focused on just the first battery in the bank.

We feel that AGM batteries are superior to wet cell (flooded) batteries because they can be installed in any orientation, don’t require maintenance, can’t spill (even in a capsize), and charge more quickly. Our Mastervolt batteries, like almost all AGM batteries on the market, are dual-purpose, combining the very different characteristics of both deep-cycle and start batteries. Our batteries work well, but if we were doing an installation from scratch today, we would consider the new Trojan Reliant AGM batteries. These batteries are engineered strictly for deep-cycle use and have been optimized to provide consistent current and maximize battery life.

Our boat came with a Xantrex Freedom 2,500-watt inverter/charger wired into the boat’s AC wiring system with a transfer switch. The inverter/charger performed two functions. While the boat was disconnected from shore power, it converted the batteries’ 12-volt DC power into 120-volt AC power, allowing us to operate 120-volt appliances, like our microwave. When the boat was connected to shore power, it charged the batteries.

Because this inverter/charger was a modified-sine-wave inverter, mimicking AC ­current with a stair-stepped square wave, we also had a 600-watt pure-sine-wave inverter to power our potentially more sensitive electronic devices. We chose Exeltech because its inverters produce an electrical signal that is clean enough to power medical equipment, and they are NASA’s choice for both the Russian and American sides of the International Space Station. For simplicity, rather than wiring the inverter into the cabin’s AC wiring, we plugged ordinary household power strips into the AC outlets on the inverter and plugged our appliances into the power strips. Like the charge controller, the inverter must be located as close to the batteries as possible. Ours was under a settee.

Shade’s Impact on Sailboat Solar Panels

Once our solar installation was completed on our sailboat, we closely observed the effects of shade on our solar-panel array. We were often anchored in an orientation that put the panels in full sun. Just as often, however, we were angled in such a way that shade from the mast and boom covered portions of our panels. It was fascinating to monitor the solar charge controller’s LCD display whenever the sun was forward of the beam — the current from the panels to the batteries fluctuated up and down as we swung at anchor.

Taking notes one morning, we noticed that the charging current was repeatedly creeping up and down between 9.5 and 24.5 amps as the boat moved to and fro. When the entire solar-panel array was in full sun, it generated 24.5 amps of current. When we moved so the mast shaded a portion of one panel, the array generated 15 amps. When it shaded portions of two panels and only one was in full sun, the array produced just 9.5 amps. Of course, it would have been preferable to see a steady 24.5 amps all morning, but this sure beat watching the current drop to zero whenever a shadow crossed a panel.

We discovered that shade makes a huge impact while sailing, too. Surprisingly, it is far worse to have the panels shaded by the sails than to have the panels in full sun but tilted away from its direct rays. One afternoon, we noticed that while we were on a tack that tilted the panels away from the sun, they generated 24.5 amps of current, whereas on a tack where the panels were tilted toward the sun but two of the three were partially shaded by the sails, the current dropped to a mere 10 amps.

Reflections On Our Solar Panel Installation

A wonderful and surprising side benefit of our large solar panels and arch system was that the setup created fabulous shade over the jumpseats at the stern end of the cockpit. Our metal fabricator, Alejandro, placed a support strut at hand-holding height, and sitting in those seats feels secure and comfortable while sailing, no matter the conditions.

After living on solar power for eight years of cruising and land-yacht travel, we’ve learned that you can never have too much solar power. Groovy’s 555 watts was enough to run all our household appliances as needed, including our nearly 4-cubic-foot DC refrigerator, two laptops, a TV/DVD player, and lights at night. However, it was not quite enough power to run all that plus our stand-alone 2.5-cubic-foot DC freezer during the short days and low sun angles of the winter months without supplemental charging from the engine alternator every few days. For the 10 weeks that we did not have a functioning alternator, our solution was to turn off the freezer, which enabled our batteries to reach full charge every afternoon.

Solar power made a world of difference in our cruise. Not only did it allow us to live comfortably and with ample electricity for weeks on end when our engine alternator went on the blink, but as a “set-it-and-forget-it” system, it also gave us the freedom to anchor out for as long as we wished without worrying about the batteries. In our eyes, the solar-panel arch enhanced the beauty and lines of our boat, giving her a sleek and clean appearance. It was true icing on the cake to discover that the panels and arch system also provided much-needed shade over the cockpit and helm from the hot tropical sunshine. If you are preparing for a cruise, consider turning to the sun for electricity and outfitting your sailboat with solar power.

The Installation:

Emily and Mark Fagan offer cruising tips and share their stories and photos on their website, roadslesstraveled.us . They are currently enjoying a land cruise across America aboard an RV.

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Choosing a hybrid wind/solar charge controller

• Thread starter patrickkidd
• Start date Apr 27, 2017
• Tags solar wind
• Forums for All Owners
• Ask All Sailors

patrickkidd

Hi there! I am looking at wind and solar power, to power a NorCold 2.5A icebox conversion kit (fridge), a Dickinson NewPort (diesel heater) high pressure fuel pump, and the usual cabin lights and phone/laptop chargers. It looks like a 300W or so wind generator and 2x100W solar panels (batwing-style: one on each side of cockpit railing?) and 100ah battery will probably do it for San Francisco Bay. There is never a cloudy day with no wind here. There is a ton of gear out there and it's hard to tell what is quality and what is not, especially for hybrid wind/solar charge controllers. What have you used? Any brand names you would recommend? I'd like to keep the budget reasonably mid-range. Thanks!  

Need to know total per hr amp draw! (24 hr AVG amp draw per hr also needed) Why a special controller? Why wind? Early indicator is; you will be wasting lots of money! ONLY a 100 ah battery? I hope you havn't bought anything yet, as you need lots of help. Chief  

Chief RA said: Need to know total per hr amp draw! (24 hr AVG amp draw per hr also needed) Why a special controller? Why wind? Early indicator is; you will be wasting lots of money! ONLY a 100 ah battery? I hope you havn't bought anything yet, as you need lots of help. Chief Click to expand

Start out with doubling on batteries and expand if necessary. The reason I questioned both pwr sources is using one might save you money. Using both does provide versatility though for SF. My observation concerning wind is the vibration problem as well as the noise. I hate the boat buzz. Solar power is a great source. In your case 200w might be a bit light though. Remember, solar is only there for less than 1/2 the day! Calculate accordingly! Mounting is best across the stern on a rack. MPPT is the way to go but I am not aware of the need for a special controller for wind generation voltage. I did a quick check on Amazon though and the special wind turbine controllers do not seem to be much different in cost. Wind turbines are on Amazon at reasonable cost for 300w units, and with reviews. Shop to cut your costs! Are you related to Admiral Kidd? Served in USS Kidd, DD 661, now a museum at Baton Rouge! Good luck, Chief  

Patrick - I like your style of looking into and investigating this new upgrade. The devil is in the details and this is an interesting project. Question: Should we be responding with the assumption you’re on the Bay or in Alaska? My preference is to have a high voltage/current capability for all the motor driven devices because they just start running better. The refrigeration falls into that category, but then there is the water pump, auto pilot, forced air heater (if there is one), etc. I also upped the wire size where ever I could to minimize voltage drop for the inrush current. Having a pair of solar panels to help with the voltage and current for motor devices is being really kind to them so that’s really good. Our boat has a pair of Kyocera 130W panels and I also have a Rutland 6-blade (1-meter diameter) wind generator but my instillation is over 20 years old now. The panels go to a Blue Sky controller and the Rutland has it’s own controller. There has been a lot of change since I put the system together but I’d like to see what you come up with. My battery bank is 4 golf carts and I used to have a group 27 start battery but it has been removed because it seems redundant. For a start battery I found that even a small car battery actually does a better job of spinning the engine! Go figure. The Rutland isn’t what I’d call bothersome noisy at all. It is mounted on the stern opposite the radar and from our aft cabin one can barely hear it. Some areas where we cruise tend to have fairly good wind at night in the summer due (I believe) to the warm land mass and cool ocean.so the wind generator does well. On the other hand, with the long summer days the solar panels also do well but the days start getting short really fast in September. If you’re in Southeast Alaska with this rig then a wind generator would be helpful as the days are often cloudy and overcast due to inclement weather. For the moment until there is a little more information, for the Bay Area, my initial suggestion would be to try four golf carts if there is room and the solar panels then see how it goes. As for a wind gen “break”, our Rutland doesn’t have one. I attached a tether to the end of the vane and turn the unit around until the blades stop, wrap the tether once around one of the blades and then around the mast, above the braces, and call it good. The wind gen can then rotate on it’s own any way it wants to.  

John Nantz said: Patrick - I like your style of looking into and investigating this new upgrade. The devil is in the details and this is an interesting project. Question: Should we be responding with the assumption you’re on the Bay or in Alaska? My preference is to have a high voltage/current capability for all the motor driven devices because they just start running better. The refrigeration falls into that category, but then there is the water pump, auto pilot, forced air heater (if there is one), etc. I also upped the wire size where ever I could to minimize voltage drop for the inrush current. Having a pair of solar panels to help with the voltage and current for motor devices is being really kind to them so that’s really good. Our boat has a pair of Kyocera 130W panels and I also have a Rutland 6-blade (1-meter diameter) wind generator but my instillation is over 20 years old now. The panels go to a Blue Sky controller and the Rutland has it’s own controller. There has been a lot of change since I put the system together but I’d like to see what you come up with. My battery bank is 4 golf carts and I used to have a group 27 start battery but it has been removed because it seems redundant. For a start battery I found that even a small car battery actually does a better job of spinning the engine! Go figure. The Rutland isn’t what I’d call bothersome noisy at all. It is mounted on the stern opposite the radar and from our aft cabin one can barely hear it. Some areas where we cruise tend to have fairly good wind at night in the summer due (I believe) to the warm land mass and cool ocean.so the wind generator does well. On the other hand, with the long summer days the solar panels also do well but the days start getting short really fast in September. If you’re in Southeast Alaska with this rig then a wind generator would be helpful as the days are often cloudy and overcast due to inclement weather. For the moment until there is a little more information, for the Bay Area, my initial suggestion would be to try four golf carts if there is room and the solar panels then see how it goes. As for a wind gen “break”, our Rutland doesn’t have one. I attached a tether to the end of the vane and turn the unit around until the blades stop, wrap the tether once around one of the blades and then around the mast, above the braces, and call it good. The wind gen can then rotate on it’s own any way it wants to. Click to expand

patrickkidd said: ... But for the record, my daily minimum is fridge: 1.25ah , electronics: 6ah, fuel pump: 1ah = 8.25ah. Click to expand

SFS: My reefer only draws .7 ah and it is 2.8 cu ft. My solar is 2.5 ah. Chief  

SFS said: We don't have one, so I'll admit my ignorance, but this seems like an incredibly small amount of current to run a fridge for a day. Can you tell me what you have? I'll buy one tomorrow. Click to expand

patrickkidd said: These values are estimated in amp hours per day. The fridge draws 2.5A when the compressor is running, and runs about half of the time I suppose. It is the NorCold icebox conversion kit. I couldn't speak higher of it. Click to expand

patrickkidd said: These values are estimated in amp hours per day . The fridge draws 2.5A when the compressor is running, and runs about half of the time I suppose. It is the NorCold icebox conversion kit. I couldn't speak higher of it. Click to expand

His estimate of work time is about right. My reefer runs about 50% of the time and my amps are correct as well. The newest reefers do not use near as much power as the old ones. The per day statement is probably confusing the values. He is using about 30 amps per day since 2.5a x 12hrs is the calculation and that is because it is a new system. Chief ARF145: I posted this while you were posting yours. Yes, my reefer averages .7a per hour over a 24 hr period. Will provide model info. Please note that I am an Electronic Eng!  

And your make and model of reefer?  

Stu Jackson

Patrick, I sailed SF Bay for 35 years. A 100ah battery UNLESS you are palnning to marina hop (in which case solar and wind would make NO sense) is plainly speaking ludicrous. Minimum 200ah bank, but 400 would be about right for anchoring out for two nights with no engine run. I did that regularly with no solar. Wind on SF Bay is there, for sure. But when you stop for the night you want a quiet spot and no wind. The wind STOPS at night on the Bay and in the Delta. It's foggy in the mornings, many times until 1200, and sometimes the fog never lifts. Your weather comments are simply incorrect. Solar is good. Your numbers, as Chief said, are way off. You need to learn to do the math properly. My fridge draws 5A when running 50% of the time. 5 * 0.5 * 24 = 60 ah per day. Many of the topics on this link may help you out. Electrical Systems 101 http://c34.org/bbs/index.php/topic,5977.0.html http://c34.org/bbs/index.php/topic,5977.0.html Good luck.  

I have an Iso-therm reefer sold for trucker use. Bought in 2013 and can't find model online anymore. Just go to Iso-therm online and check out existing units for sale. Chief Hi Stu! Thanks for the help. Chief  

SFS said: Ok, so you are not doing the math correctly. If the compressor runs 1/2 the time (12 hours a day), then 2.5 amps times 12 hours is 30 Ah, not 1.25 Ah, which is what you originally stated. There are lots of posts here on energy budgets, which is ALWAYS where you need to start. Chief is probably right, it looks like you need a lot of help here. Do some more research, and talk to fellow skippers about their systems, and ask more questions here. You may want to check out Maine Sail's site (marinehowto.com, I think). He is THE go-to resource on stuff like this. No sense in reinventing the wheel. @Chief RA , current is measured in amps, not in Ah. Are you saying your refrigerator draws 0.7 amps when the compressor is running? If so, I'd like the make and model number. What percentage of the time does the compressor run? Is it DC only, or will it run on AC when you are at the dock? Or are you saying that you average 0.7 Ah every hour around the clock, for a total of about 16.8 Ah in each 24-hour period? Click to expand

Stu Jackson said: Patrick, I sailed SF Bay for 35 years. A 100ah battery UNLESS you are palnning to marina hop (in which case solar and wind would make NO sense) is plainly speaking ludicrous. Minimum 200ah bank, but 400 would be about right for anchoring out for two nights with no engine run. I did that regularly with no solar. Wind on SF Bay is there, for sure. But when you stop for the night you want a quiet spot and no wind. The wind STOPS at night on the Bay and in the Delta. It's foggy in the mornings, many times until 1200, and sometimes the fog never lifts. Your weather comments are simply incorrect. Solar is good. Your numbers, as Chief said, are way off. You need to learn to do the math properly. My fridge draws 5A when running 50% of the time. 5 * 0.5 * 24 = 60 ah per day. Many of the topics on this link may help you out. Electrical Systems 101 http://c34.org/bbs/index.php/topic,5977.0.html Good luck. Click to expand

OK, poly 2 ea. 100w panels (30a controller) mounted on high ss rack w/ adj. angles to align with sun. They feed 2 ea size 24 Walmart wet cells, 100ah ea.. 9.9 hp Tohatsu provides up to 7a at 12v to batteries when running. Powers reefer (-.7ah) 15" DC TV (-2ah) LED boat lighting, electronic charging maybe -1a. This system is not new as Mono panels would be better, 4 golf cart batteries will eventually replace the 24's but it handles the 25' Catalina 250 quite well and it is self sufficient when decent sun. Hope this is more what you ask for. Are you related to Admiral Kidd? Chief  

Chief RA said: OK, poly 2 ea. 100w panels (30a controller) mounted on high ss rack w/ adj. angles to align with sun. They feed 2 ea size 24 Walmart wet cells, 100ah ea.. 9.9 hp Tohatsu provides up to 7a at 12v to batteries when running. Powers reefer (-.7ah) 15" DC TV (-2ah) LED boat lighting, electronic charging maybe -1a. This system is not new as Mono panels would be better, 4 golf cart batteries will eventually replace the 24's but it handles the 25' Catalina 250 quite well and it is self sufficient when decent sun. Hope this is more what you ask for. Are you related to Admiral Kidd? Chief Click to expand

patrickkidd said: There is a ton of gear out there and it's hard to tell what is quality and what is not, especially for hybrid wind/solar charge controllers. What have you used? Any brand names you would recommend? Click to expand

Chief RA said: His estimate of work time is about right. My reefer runs about 50% of the time and my amps are correct as well. The newest reefers do not use near as much power as the old ones. The per day statement is probably confusing the values. He is using about 30 amps per day since 2.5a x 12hrs is the calculation and that is because it is a new system. Chief Click to expand

Chief RA said: ARF145: I posted this while you were posting yours. Yes, my reefer averages .7a per hour over a 24 hr period. Will provide model info. Please note that I am an Electronic Eng ! Click to expand

Maine Sail: I do not need any corrections in terminology from you! You are not the resident authority, your title is Moderator. You are knowledgable but be more aware that many of us are as well. Sharpshooting is a cheap way to make yourself sound more important than you are! I resent your attitude and your conduct. I am not an Electrician Engineer. I am both an Electronic Engineer and Industrial Engineer. Chief  

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Guide to Equipping Your Boat with Solar Power: A Complete System Breakdown

Posted by Tina Kassaeian on July 7, 2023

As boaters increasingly prioritize environmentally friendly and sustainable power solutions, harnessing solar power has gained popularity. In this comprehensive guide, we will explore the essential components necessary to create a reliable and efficient solar power system for your boat. From solar panels and batteries to inverters and solar charge controllers , we will provide an in-depth explanation of each component. 

By the end of this guide, you'll have a clear understanding of how to equip your boat with a robust solar power system.

Understanding the Components of a Boat Solar Power System

Solar panels: the backbone of your system.

Solar panels are crucial components of a boat solar power system as they convert sunlight into usable electricity to power your boat's electrical devices. There are various types of solar panels available, including monocrystalline, polycrystalline, and thin-film panels.

Efficiency: Monocrystalline solar panels are known for their high energy conversion efficiency. This means they can generate more electricity from the same amount of sunlight, making them a suitable choice for boats with limited space for solar panel installation.

Factors to Consider

• Panel Sizing: Assessing your energy needs and available space will help determine the appropriate size and number of panels required for your boat.
• Placement: Solar panels should be placed in an area on your boat that receives maximum sunlight exposure throughout the day, typically on the deck or roof. Avoid shading from obstacles like antennas or sails.
• Tilt Angles: Adjusting the tilt angle of the panels seasonally can optimize their performance. Tilting the panels toward the sun's angle during winter and adjusting them to a flatter angle during summer maximizes energy generation.

Installation Considerations

Mounting: Securely mounting the panels using appropriate hardware and brackets ensures they remain in place even during rough waters.

Wiring: Properly routing and protecting the wiring from the panels to the battery bank is crucial for safety and efficiency.

Maintenance: Regularly inspecting and cleaning the panels to remove dirt, debris, and salt build-up ensures optimal performance.

By selecting high-quality solar panels and considering factors like panel sizing, placement, tilt angles, and installation best practices, you can maximize the efficiency and output of your boat's solar power system.

Batteries: Storing Energy for Extended Usage

Batteries are essential components of a boat solar power system as they store the excess energy generated by the solar panels for later use, ensuring a continuous power supply even when sunlight is limited. Here are key points to consider when selecting and maintaining batteries for your system:

Importance of Selecting the Right Battery

• Capacity: The battery capacity determines the amount of energy it can store. Assess your boat's energy requirements to choose a battery with sufficient capacity to meet your needs.
• Lifespan: Consider the battery's lifespan, typically measured in cycles (number of charge and discharge cycles it can endure), and select a battery with a longer lifespan for optimal value and longevity.
• Maintenance Requirements: Some batteries require regular maintenance, such as checking water levels and specific gravity, while others are maintenance-free. Evaluate the maintenance needs and choose a battery that aligns with your preferences and abilities.

Battery Technologies

Li-ion batteries have gained popularity in marine applications due to their high energy density, lightweight design, and longer lifespan compared to traditional lead-acid batteries. They offer efficient energy storage, faster charging times, and are generally maintenance-free.

Proper Sizing and Maintenance

• Sizing: Properly sizing your battery bank involves calculating the total energy consumption and determining the number and capacity of batteries needed to meet your power requirements. Consider factors like daily energy usage, charging time, and days of autonomy (the number of days the batteries can sustain the boat without solar input).
• Maintenance: Regular battery maintenance includes monitoring the state of charge, avoiding over-discharging or overcharging, and periodic checks of connections and battery health. Adhering to the manufacturer's guidelines ensures optimal performance and extends battery life.

By selecting the right battery technology, such as lithium-ion batteries, and considering factors like capacity, lifespan, and maintenance requirements, you can ensure reliable energy storage for your boat's solar power system. Proper sizing and diligent maintenance practices will maximize the performance and lifespan of your battery bank, providing sustained power for your boating adventures.

Inverters: Converting DC Power to AC Power

Inverters are essential components of a boat solar power system as they convert the direct current (DC) power generated by solar panels and stored in batteries into alternating current (AC) power, which is used by various electrical devices onboard. Here's what you need to know about inverters:

• Functionality: Inverters take the DC power from the batteries and transform it into AC power, mimicking the power supplied by the utility grid. This enables you to power AC appliances, electronics, and devices on your boat.
• Features: Inverters can have various features, such as pure sine wave output, multiple AC outlets, built-in protection mechanisms (like overload and short-circuit protection), and remote monitoring capabilities.
• Sizing: It's crucial to properly size your inverter to meet your power requirements. Consider the wattage or power ratings of the appliances and devices you plan to power simultaneously to determine the appropriate inverter size.

Charge Controllers: Regulating the Flow of Power

Charge controllers are vital for regulating and protecting your batteries from overcharging, ensuring their longevity and optimal performance. Here's what you should know about charge controllers:

• Functions: Charge controllers monitor the state of charge of your batteries, regulate the flow of power from the solar panels to the batteries, and prevent overcharging. They may also provide additional features like load control and battery temperature monitoring.
• Types: There are primarily two types of charge controllers: PWM (Pulse Width Modulation) and MPPT (Maximum Power Point Tracking). MPPT charge controllers are more efficient and can extract more power from the solar panels, particularly in situations with lower solar panel voltage than the battery bank voltage.

Wiring and Connectors: Ensuring a Reliable Connection

Proper wiring and connectors are essential for effectively transferring power between the solar panels, batteries, and other components of your boat's solar power system. Here are key considerations:

• Types of Wiring: Marine-grade and UV-resistant wiring should be used to withstand the harsh marine environment. Tinned copper wire is commonly used due to its corrosion resistance and superior conductivity.
• Wiring Protection: Adequate protection, such as conduit or wire looms, should be employed to safeguard the wiring from physical damage, UV exposure, and moisture.
• Connectors: High-quality connectors designed for marine use, such as waterproof and corrosion-resistant connectors, ensure reliable electrical connections and minimize power losses.

Selecting the Best Components for Your Boat Solar Power System

Volts energies 100ah battery: power and reliability.

The Volts Energies 100AH battery stands out as an excellent choice for powering your boat. With its robust construction, long lifespan, and high energy density, this battery offers exceptional performance and reliability. 

Its advanced technology ensures efficient energy storage and discharge, allowing you to meet the power demands of your boat while maintaining optimal system performance.

Volts Energies Mono Solar Panels: Efficiency and Durability

When it comes to solar panels for your boat, Volts Energies Mono Solar Panels excel in both efficiency and durability. These panels utilize monocrystalline technology, which maximizes their energy conversion efficiency, ensuring you can generate more power with limited space. 

Additionally, they are designed to withstand harsh marine environments, featuring corrosion-resistant materials and reinforced frames to ensure long-lasting performance.

Victron Inverter: Reliable Power Conversion

Choosing a reliable inverter is crucial for converting the DC power stored in your batteries into AC power for your boat's electrical devices. Victron inverters are renowned for their high-quality construction, advanced power electronics, and robust performance. 

With features such as pure sine wave output, high surge power capacity, and excellent load handling capabilities, Victron inverters provide stable and clean power for sensitive electronics onboard your boat.

Victron Charge Controller: Optimal Battery Management

To regulate the flow of power and protect your battery bank, a high-quality charge controller is essential. Victron charge controllers offer advanced MPPT (Maximum Power Point Tracking) technology, ensuring optimal energy harvest from your solar panels. 

They also provide comprehensive battery management features, such as temperature compensation and intelligent charging algorithms, to prolong the lifespan of your batteries and maximize their performance.

Building a robust solar power system for your boat is a wise investment, providing reliable power while minimizing your environmental impact. Incorporating the Volts Energies 100AH battery, Volts Energies Mono Solar Panels, and Victron inverter ensures a highly efficient and durable setup for your marine adventures. 

With careful consideration of each component and proper installation, you can enjoy a sustainable and independent power source while cruising on your boat. Contact Volts Energies in Canada to explore the best solar and renewable energy equipment options and embark on your journey to greener boating today.

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Soak up the Sun: The 5 Best Solar Battery Chargers for Boats

It's a tale as old as (modern) time. You're in the middle of a favorite show and you get that low-battery warning. We've all been there. 

It's no fun when your electronic devices lose power. It's bad enough when you're at home and have to stay attached to the wall. It's a different story when you're off-the-grid and anchored out on your boat. 

From chartplotters, GPS, VHF radios and cell phones to fish finders, stereos and blenders (can't leave out the blender), you need electronic devices on a boat for safety, information, entertainment and what-not. And that means a power source of some sort.

This is where solar panels and solar battery chargers for boats come into play.

Charging everything up at home or in the marina is always a great idea. But what if you're out on the high seas? Or high lake, for that matter.

Read on to find out how handy and efficient boat solar battery chargers can be. 

What Is a Solar Battery Charger for a Boat?

A solar battery charger for a boat has two basic parts that work together. The solar panel collects energy from the sun. This energy then goes to the charge controller , which regulates, stores and distributes it.

All of that collected energy is then deposited into your battery bank (think of it as your very own bank teller, of sorts). Then, when you need it, you simply attach it to your electronic device.

If the battery is completely empty, the charge controller puts as much energy as possible into it until it reaches a full charge. At this point, it goes into float mode , which maintains the power level automatically.

The charge controller is a great piece of gear as it improves the charge quality and prevents the battery from overcharging and from loose connections.

From wind generators and solar panels to boat solar battery chargers, renewable energy is a free (after the initial purchase of the capturing equipment) and a smart way to go about boating.

Let's discuss more about solar battery chargers and how they can provide power and peace of mind for days (and nights) out on the sailboat, liveaboard trawler , pontoon boat or sport fishing boat. Even kayakers can benefit from small solar panel battery chargers.

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Features of Solar Battery Charger Systems

Charge controller.

Also known as a regulator, the charge controller is what puts the energy into your battery. It's very possible to have a solar panel without one. But you'll want to make sure you choose a panel that comes with a charge controller.

Charge controllers are necessary if the panel is more than five watts. The best thing about the charge controller is that it can store the energy for later use. A solar panel alone needs sunlight to work.

Solar Panels

The solar panel is the part that collects the energy from the sun. You've likely seen them on house rooftops. They're becoming more and more prevalent on boats.

Pulse Width Modulation

Pulse width modulation (PWM) is the temperature compensation that protects the battery from things like overcharging and frequent charging. This is a must-have safety and efficiency feature. You don't want to have to go out and buy new batteries every Monday.

Self-regulation

Self-regulating boat solar battery chargers don't have a built-in controller. Every boater is different, of course, but anything built-in is a positive feature in my opinion.

Plastic and Aluminum Construction

Plastic and aluminum mean less breakage and more weather resistance. Wind, sun and saltwater (and water in general) can be rough on any piece of boating gear  as well as anchors , ratchet straps and dock lines .

Types of Solar Battery Chargers for Boats

• Boost Charging  provides a high current for a short time to fully charge the battery
• Trickle Chargers provide a very low level of output by continuously releasing a small amount of power to charge the battery as you use it
• Float Chargers are similar to the trickle charger, but they prevent overcharging (this type is my pick for the best all-around solar battery charger)

The 5 Best Solar Battery Chargers for Boats

So, we've come to the conclusion that solar battery chargers are a great investment for liveaboards, recreational boat and even fishing kayaks and jet skis.

Let's take a look at some examples for purchasing options.

1. Eco Worthy Portable Folding Solar Charger and Panel

The Eco Worthy Folding Solar Panel comes pre-wired and pre-installed with a 15 Amp PWM solar charge controller that protects from overcharging and reverse connections. The high-efficiency  monocrystalline solar cell is made of lightweight aluminum .

Its suitcase-style design makes it easy to transport . When you get where you're going, just unfold and set it up.

The charge controller has waterproof integrated junction boxes , and there's a corrosion-resistant frame on the panel.

This is a nice mid-sized panel and solar battery charger. Best part? All that pre-wiring and pre-installing makes it ready to use right out of the box .

• Size : 30.7" x 22.1" x 5.1"
• Charger Type : Float Charger
• Panel Type : Monocrystalline

2. HQST Solar Battery Charger and Panel

The HQST provides quiet power production for 12 and 24-volts in marine and other outdoor and off-the-grid environments. It has a 30A PWM LCD charge controller with LCD display, 20-foot adapter cables and a set of Z-brackets for mounting.

It can charge a 50Ah battery from 50% in three hours (depending on the sunlight, of course). Pre-drilled holes make the panel easy to install. You can expand your solar system by connecting other panels for even more energy output.

• Size : 40" x 27" x 1.5"
• Charger Type : Trickle Charger
• Panel Type : Polycrystalline

3. POWISER Solar Battery Charger and Panel

The POWISER 3.3W is an easy-to-connect and use trickle charger . It has polycrystalline high-efficiency solar cells with thin amorphous panels that allow it to be used in any weather.

Compact in size, it's perfect for jet skis and small boats . It even comes with suction cups to attach to your boat's window . I really like the compact size and shape of this solar panel and battery charger.

• Size : 14" x 8.5" x 0.8"

4. SOLPERK 12V Solar Battery Charger and Panel

The SOLPERK 12V Solar Panel is a trickle charger. It charges and maintains 12V batteries like Wet, Gel, MF and many more. The automatic charging and maintenance controller provides protection against short circuits, open circuits, reverse and overcharging.

It's lightweight and easy to install on jet skis and small boats . The best thing about the SOLPERK? It has thin film amorphous solar cells that allow it to work on cloudy days. Win/Win!

• Size : 21.3" x 18.2" x 1.2"
• Panel Type : Amorphous solar cells

5. Sunway Solar Solar Battery Charger

Small and compact, the Sunway Solar Battery Trickle Charger slowly charges and maintains battery power levels in Wet, Gel, Deep Cycle and AGM batteries. A built-in diode protects against reverse charging.

Crystalline panels have clear PV glass and ABS plastic housing for efficiency and durability. The long rectangular shape of the Sunway makes it a good choice for mounting on a dash or bow of the boat.

The charger maintainer has a cigarette lighter adapter and alligator battery terminal clips .

• Size : 13.9" x 0.5" x 5"
• Panel Type : Crystalline

Cleaning Solar Panels

As with any boating accessory, cleaning and general maintenance are needed for solar panels. Luckily, it's not too hard. Rainfall is a handy thing to have in this case. For more in-depth cleaning, here are a few tips. 

• Use a soft brush to swipe away any caked-on dirt, grime and the inevitable bird droppings. You may need an extension rod for this job.
• Next, get out that garden hose and spray away. A boat hose nozzle with an adjustable water stream is an excellent tool to have. You don't want to shoot your panels with a heavy stream of water. 
• A microfiber sponge or cloth is helpful if there are still stains and dirt to scrap away.
• Using soap is not suggested as it can leave a residue that will attract dirt. Try a small amount of Better Boat Boat Soap to see how it does with your particular solar panels. It's 100% biodegradable and designed to rinse clean and residue free.

As you can see, you have a lot of choices when it comes to keeping batteries charged out on the water. Hopefully, this has shed some light (pun intended) on your boat solar battery charger questions.

May the wind be at your back and your batteries always be full.

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The Best Solar Panels for Boats of 2024

Solar panels are a great way to give your boat energy and power. If you like taking long rides on motorized watercraft, having solar panels can reduce your energy costs. They also make sure that the boat is efficient and never runs out of power in an emergency. There are multiple options for solar panels available, which can make the market search even more confusing. To help you find a suitable pick, we have shortlisted and keenly reviewed our favorite solar panels for boats in 2024.

A top-quality product not only lasts long but also delivers efficient results. This is why it is essential to invest your money in high-end solar panels. All our products are selected based on their overall performance and ability to deliver high-end results.

Our Top Picks

• Best Overall: Renogy Solar Panels for Boats Shop Now ➔
• Most Lightweight Design: Rophie Solar Panels for Boats Shop Now ➔
• Premium Kit: TopSolar Solar Panels for Boats Shop Now ➔
• Best Backup Kit: ECO-WORTHY Solar Panels for Boats Shop Now ➔
• Simple Installation: Sunway Solar Panels for Boats Shop Now ➔
• Premier Foldable Panel: EF ECOFLOW Solar Panels for Boats Shop Now ➔
• 1 What to Consider When Buying Solar Panels? 
• 2 Size 
• 3 Type 
• 4 Accessories 
• 5 How Do Solar Panels for Boats Work? 
• 6 Installation
• 7 What Are Care Requirements to Enhance the Life of Solar Panels for Boats? 
• 9 Cleaning 
• 10 What Are the Properties of Charge Controllers for Solar Panels for Boats? 
• 11 Basic charge controllers 
• 12 Mid-range charge controllers
• 13 Max power charge controllers 
• 14 Conclusion 

Can solar panels for boats run a trolling boat motor?

How long does it take for a solar panel to charge your boat’s battery, why do people consider installing solar panels for boats, the best solar panels for boats, best overall.

Renogy Solar Panels for Boats

The Renogy are 100W monocrystalline solar panels providing an average of 400-500Wh or 33-41Ah of electricity per day, so you have reliable performance. It has bypass diodes that protect the solar cells from overheating, so you don’t have to worry about maintenance. In addition, it features a corrosion-resistant aluminum train providing extended outdoor use without any extra damage.

These solar panels come with pre-drilled holes on the back so that you can install and mount them without spending money on professional help. They measure 42.2 x 19.6 x 1.38 inches and weigh 14.3 pounds, making them lightweight and convenient. Moreover, you can install them on boats, rooftops, cabins, and more for multifunctional use. Because of their efficiency and reliability, these solar panels stand at the top of our list.

• They are weather-resistant 
• These solar panels maintain cell temperature 
• Provide reliable performance
• Only compatible with Renogy ground mounts and brackets

Most Lightweight Design

Rophie Solar Panels for Boats

The Rophie Solar Panels easily stands out on this list. Designed with impeccable efficiency, they accelerate solar charging to the next level, making it ideal for outdoor enthusiasts and off-grid boat owners. These solar panels convert sunlight into power rapidly, while their ultra-light, foldable design ensures convenience during transport and installation. Don’t let their light weight fool you, though, as they pack an impressive 200 watts, delivering unmatched power performance for your boat or outdoor camping.

These panels don’t just excel in efficiency and power; they’re also built to endure. Their IP67 waterproof grading ensures that they remain operational even under challenging weather conditions. Their high-quality MC-4 connectors further optimize power transfer while ensuring safe and secure connections. Plus, their compact design won’t take up much space, proving to be the optimal choice for boat owners who value both power and convenience.

• Lightweight and easily transportable
• Durable and water-resistant
• High-performance with 200W
• Can be a little pricey

Premium Kit

TopSolar Solar Panels for Boats

The TopSolar Solar Panels are available in a kit containing 20W solar panels, a solar charger regulator of 12V/24V, two 6.5-foot cables with alligator clips, and an O-ring terminal to have a complete experience while on the go. They are perfect for off-grid 12-volt battery charging systems providing you with various DC applications like cabins, boats, battery-operated gates, and more. They come with a 10A solar charger controller preventing the battery from overcharging, discharging, and risk of short circuit for a safe experience. 

These solar panels have aluminum and tempered glass frames, ensuring a durable and weather-resistant use. Weighing 2.75 pounds and measuring 2.32 x 13.86 x 17.13 inches, they are compact and portable. 

• Easy to store and carry 
• They come in a complete kit 
• Provide excellent weather resistance
• Not suitable for large areas and machinery

Best Backup Kit

ECO-WORTHY Solar Panels for Boats

The Eco-Worthy Solar Panels are 10W 12V solar car battery chargers that can be used to recharge boats, motorcycles, boats, snowmobiles, and tractors. They feature a cigarette plug option supplying you with constant power when needed. This kit includes a cigarette lighter adapter, one pair of battery clips, and four-piece PVC suckers ensuring maximum results in no time. 

They also have energy-saving, built-in blocking diodes that prevent reverse discharge from maintaining and extending battery life for maximum durability. It measures 1.4 x 9.6 x 15.3 inches and weighs only 1.5 pounds, so you have a compact product at hand

• They are available in a complete kit 
• These panels are lightweight and compact 
• They can recharge different types of vehicles
• Only designed for vehicles

Simple Installation

Sunway Solar Panels for Boats

The Sunway Solar Panels are battery charger panel mounts that require a simple installation on any windshield or dash, giving you a quick and convenient experience. They come with 12-volt batteries and a maintainer that protect your panels from overheating and discharging, ensuring safe and convenient use. In addition, these panels are equipped with ultra-clear PC glass, so you have a strong and durable product. 

They contain built-in blocking diodes that prevent reverse charging allowing your battery to maintain its useful life. Moreover, they also come with a blinking LED charge indicator that lets you know when the job is done.

• Comes with a battery maintainer
• Do not require professional installation 
• Comes with charging indicators
• Suitable to recharge small batteries only

Premier Foldable Panel

EF ECOFLOW Solar Panels for Boats

The EF Ecoflow provides 160W solar portable and foldable solar panels, delivering a compact and easy-to-carry experience. They are designed to produce maximum power at any time of the day when paired with an EcoFlow power station, so you never run out of electricity. Moreover, they have a seamless one-piece waterproof design, so you can use them during outdoor activities like camping and hiking. 

These solar panels are also equipped with protection during transportation, enabling you to carry them without any concerns. Each pack comes with an Ecoflow 160W solar panel, kickstand case, user manual, and warranty card, so you don’t have to make any additional purchases. 

• They can be folded for easy storage 
• Comes in a complete kit
• Suitable for different outdoor activities
• Can only be paired with an Ecoflow power station

Solar Panels for Boats Buying Guide

We have compiled a detailed buying guide to help you pick a suitable product. It will give you an idea about your requirements for solar panels for boats. 

What to Consider When Buying Solar Panels? 

Since solar panels are an expensive addition to your asset list, here are a couple of essentials to remember when purchasing. 

The size of panels is directly related to the size of your boat. You must get something to match the energy requirements of your boat or greater. A solar panel too small might not power it and leave you frustrated. Other than this, smaller products have less battery time which means they will turn off much quicker than something explicitly designed for the size of your boat. 

From PVC to glass covering and fully flexible panels, the type you choose determines their cost. This helps you establish your budget according to your needs. A glass-fronted solar panel is among the most budget-friendly options, but they are not as weather resistant. Besides this, a polycarbonate version is more expensive, but they are incredibly weather resistant and have a longer life. 

Accessories 

A charge controller or maintainer is an essential component available for your boat’s solar panels. This product protects your panels from battery damage. They prevent any risk of overheating, battery discharge, or sudden drops. A charge controller is essential if you want to elongate the battery’s life. Most brands also offer mount brackets, so you don’t have to purchase them separately. 

How Do Solar Panels for Boats Work? 

Solar panels for boats work just like any other portable energy provider. To install it successfully, you must have four components: the solar panel itself, charge controller, inverter, and battery. When solar panels in the boat hit sunlight, they convert it into the electrical current, supplying your boat with the required energy. 

Boat solar panels can work without a charger maintainer (controller), but there is a risk of overcharging your device. Therefore, you must keep it in place to avoid any risk of battery damage. 

The need for an inverter depends on the number of appliances that need a charge. For instance, if you wish to charge multiple devices other than the boat, consider buying a large-capacity product. 

You can opt for professional installation if offered by the brand or any other reputed company. But individuals who have the basics can do it all by themselves. However, you must make sure that all the relevant accessories are available at your convenience. 

Installation

The installation method is divided into three main stages. The first stage is to conduct an energy assessment. In this, you will determine the level of energy that your boat needs to function. Buy a panel that has a higher voltage than your requirements. This gives more room and flexibility to charge other devices. 

Check whether the solar panel can produce that level of energy. Once the capacity is determined, you can decide the exterior of your panels. In most cases, you choose between glass-fronted, polycarbonate, and fully flexible panels. 

What Are Care Requirements to Enhance the Life of Solar Panels for Boats? 

Caring for solar panels is essential as they are a long-term investment and should last accordingly.

Most solar panels are designed to last two to three decades. Caring for them is fairly simple but requires regular attention. All you have to do is keep them clean from dirt, leaves, and other obstructions. Solar panels from reputable brands always come with a warranty for a couple of years. 

Always get a professional repair from the brand in case of any damage. Even if your warranty has expired, we recommend taking your boat’s solar panels to a professional. They might cost a bit more than a local mechanic, but your panels get the treatment they require. 

Another factor to consider here is the useful life of your solar panel. This indicates that they will not be as effective as they age. The depreciation in their quality is slow and gradual. 

If your product has met the end of its useful life, it won’t stop working but will get more prone to damage. So instead of getting frustrated with why your solar panel for boats isn’t working properly, consider getting a replacement from the same brand or changing your product. 

Cleaning 

To clean a solar panel, use lukewarm water with a mild, non-acidic detergent and apply water pressure to remove any visible dirt and debris. Panels for boats are relatively smaller, so you won’t need a lot of supply. Clean any unwanted spots with a damp cloth and leave it to dry. Avoid applying water pressure on smaller models as they might not sustain the burden.

What Are the Properties of Charge Controllers for Solar Panels for Boats? 

Charge controllers are an essential component. They help protect your panels’ battery from damage. There are three main types of charge controllers available. 

Basic charge controllers 

They use pulse width modulation to encode transmission information allowing control of the power supplied to boats or other devices. These are simple chargers that come in at an affordable price range. A primary charge controller is designed to control batteries of smaller solar panels. They might not deliver desirable results if connected with a high-capacity panel. 

Mid-range charge controllers

These controllers also use pulse width modulation but feature an LCD display to indicate current charging levels. This helps the user keep track of the system and unplug the device when it’s ready to use. 

Max power charge controllers 

Designed for high-end and powerful solar panels, they are one of the most expensive charge controllers. You should only attach them to devices recommended by the brand itself. They also maximize the performance of panels. 

Conclusion 

Solar panels are a great way to maximize energy efficiency in your boat and create a durable backup. They are available in different sizes and capacities, so you can find a suitable fit for your boat. This article carefully reviewed the most in-demand solar panels for boats in 2023 that can make a difference in your overall experience. Besides the panel, you should also grab a top-notch charge controller that protects the device from damage and enhances its life.

People Also Asked

Yes, you can run a trolling motor with solar panels, but it is essential to opt for a device that has suitable capacity.

If the panel is according to the desired capacity of the boat, it might take 4 to 6 hours for a full charge.

Solar panels reduce carbon emissions and save money by reducing fuel costs. They also reduce the noise levels caused by a fuel-ignited engine.

Article Contributors

Sail magazine review team.

SAIL Magazine Review Team reports on best-selling products in sailing and boating. The SAIL Magazine editorial staff is not involved in the creation of this content. SAIL Magazine is reader-supported: When you buy through links on our site, we may earn an affiliate commission. The SAIL Review Team is composed of authors, editors, and sailors. Artificial Intelligence (large language models) may have been used in the research and creation of the content.

To ensure questions about product testing or a specific article are addressed, please contact [email protected]

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What Size Solar Battery Charger for Boat

If you are a boating enthusiast, you understand the importance of having a reliable and sustainable power source for your boat batteries. Whether you're fishing , cruising, or camping, you need constant and dependable power to make your marine experience comfortable and enjoyable.

Fortunately, there is a reliable and sustainable way to power your boat battery - harnessing solar energy using a solar battery charger!

Solar power is an easy and cost-effective way to keep your gadgets and appliances running smoothly. With the right size of solar charger, you can easily keep your boat powered up, no matter where you are.

In this article, we will guide you on how to determine the right size solar-powered battery charger, and provide you with valuable information to help you choose the best Jackery solar generator  for your needs .

Features of a Solar-Powered Battery Charger  

A solar-powered battery charger is a system that harnesses the sun's powerful energy to generate electricity. It typically consists of a solar panel, a solar charge controller, and wiring to connect everything together.

The solar panel converts sunlight into electrical energy, while the charge controller regulates the amount of power going into the battery. It also prevents overcharging and ensures that the batteries are charged efficiently. The wiring ensures a safe and efficient connection between the components.

Solar Panels

There are three major types of solar panels available: monocrystalline, polycrystalline, and thin film panels. They all vary in appearance, performance, and cost.

• Monocrystalline solar panels (Mono-SI)

Monocrystalline panels are made from a single, pure crystal structure, which provides maximum efficiency and performance. The high-quality monocrystalline silicon allows these panels to deliver higher power output, occupy less space, and last longer than any other type of solar panel. This makes them the go-to option for many boat owners to provide power for appliances like TV, microwaves, and air conditioning.

They have a uniform dark look and rounded edges that are easy to recognize. Jackery SolarSaga 200W Solar Panel  is an excellent example of a monocrystalline solar panel. With over 23.7% efficiency, this panel can deliver maximum power output, allowing you to explore some of the most beautiful off-grid places.

• Polycrystalline solar panels (Poly-SI)

Polycrystalline panels are made of multiple interconnected crystalline silicon cells, which provide relative efficiency (around 15%) to monocrystalline panels but at a lower cost. These panels have the same dark, uniform look as monocrystalline panels, but the cells have a distinct square shape.

• Thin film panels

If you are looking for a less expensive option, you can consider thin-film solar panels. These are made of amorphous silicon deposited in layers onto a substrate to form solar cells. This makes them lightweight and flexible, making them easier to install.

However, these panels are less efficient and durable than mono or polycrystalline panels. They are also more sensitive to heat, which can reduce their power output.

Solar Charge Controller  

A solar charge controller keeps the boat's battery from overcharging by regulating the amperage and voltage delivered to the battery. This component is essential to prolong the life of your solar charger battery and prevent any damage.

It allows smooths charging, maximizing the current up to approximately 80%, then reducing it as the battery reaches full capacity, and finally maintaining a "float" or "trickle" charge to keep the battery full and ready for use. Jackery's solar generator has an advanced MPPT solar charge controller to ensure your battery lasts longer.

Solar cables connect the components of a photovoltaic system and serve as a conduit where power flows from the solar panel to the battery and other devices. They are required to have resistance against UV light, extreme temperatures, and weather conditions.

The size of the cable you need depends on both your system's voltage and amperage. The thicker the wire; the higher the amp capacity. Jackery solar battery charger for boats is equipped with high-quality, corrosion-resistant cables that are specifically designed and certified for marine environments.

Types of Solar Battery Chargers  

There are several types of solar battery chargers: Trickle charges, light-use charges, and high-output solar chargers. Each type of solar battery charger has its own specific features and capabilities, and the choice of which one to use depends on the intended application and the specific needs of the user. You want a solar panel battery charger for boats that can provide enough electricity to power your appliances while on the go.

Trickle Charging

Trickle charges are designed for maintaining the charge of a battery over a long period of time, making them ideal for use in low-power applications such as charging boats that are not used frequently.

They prevent batteries from losing charge allowing you to run all your appliances even when not sailing. These low-voltage charges are designed to improve battery health and longevity. Since all batteries self-discharge, a trickle charger can keep your boat's battery fully charged when it is on a trailer, at a mooring, or sitting at her slip.

Light-Use Charging

These are small, lightweight chargers that can be easily carried around and used to charge small electronic devices such as smartphones, tablets, and cameras. They are portable so they can be used anywhere and anytime.

Heavy Power-Use Charging

High-output solar chargers are designed for charging multiple batteries at once or for powering up large appliances, lighting systems, and other heavy-duty equipment. They can deliver high power outputs, making them ideal for use in remote off-grid locations where there is no access to traditional power sources.

Jackery's solar battery chargers are high-output solar panel kits specially designed to provide maximum power output and efficiency that are sure to make your boat's living experience enjoyable.

Benefits of Solar Battery   Charger for Boat

Installing one or more photovoltaic solar panels on your boat is a great way to keep your appliances running. They help augment or replace other power sources, such as fuel generators.

Photovoltaic solar chargers such as Jackery Solar Generator 2000 Pro  provide clean and free energy, whisper-silent operation, and zero emissions. In addition, they can also help you save money on fuel costs and reduce your environmental impact.

Harnesses the Sun’s Energy

When the sun shines onto a solar panel, it is absorbed by the photo-voltaic cells and converted into usable electricity. This energy is then used to light up your boat and power your electronics. This is a truly renewable, sustainable, and eco-friendly solution. .  

Silent and Fuel Free

This is perhaps one of the biggest advantages of using solar power. As opposed to fuel-powered generators, solar panels are whisper-silent when generating electricity. This makes them great for use on boats, where noise can be a major nuisance. They are also fuel-free, so you don't need to worry about running out of fuel when you're in the middle of nowhere.

Little to No Maintenance

Since solar panels are designed to be used outdoors, they can withstand harsh elements such as saline water and high temperatures. They also don't have moving parts, so there is virtually no maintenance required. All you need to do is keep them clean and check the wiring periodically to ensure optimum performance.

If you are looking for a reliable and sustainable way to generate electricity for your boat, solar panel battery chargers are an excellent option. They provide clean and free energy, are whisper-silent, and require little to no maintenance. When looking for a solar charging unit, you want to make sure you choose one that fits your needs, is of the highest quality and has the right features.

Jackery Solar Generator 2000 Pro is a high-output solar battery charger for boats that is specially designed to provide maximum power output and efficiency. It is perfect for use in sailboats allowing you and your loved ones to live comfortably in your sailboat and explore the great outdoors without having to worry about running out of power.

With Jackery Solar Generator 2000 Pro, you can always feel confident that you have a reliable and sustainable power source for a truly enjoyable and stress-free boating experience. So, what are you waiting for? Sign up for our newsletters to learn more about our solar panels and get exclusive offers!

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