Mounting of a solar battery charger for boat (Photo credit: BoatCrunch)

Ideally, people only go for a recreational boat tour on a bright sunny day. Rarely will anyone take out their boat on a cloudy, stormy day. Also, standard battery chargers are seldom waterproof. A combination of all these factors makes the use of solar boat battery chargers a sensible option. Since the batteries on personal boats are usually small, they have a higher likelihood of overload if you use regular solar chargers. Therefore, the best solar battery charger for boat tend to provide just the perfect amount of electricity to prevent battery overload. 

However, there are a number of considerations that must be made when choosing a solar battery charger—and this can make the entire selection process tough. Firstly, it is important to mention that solar chargers for boats are different from the ones made for phones and their use is often not interchangeable. We sieved through hundreds of products to find the best solar battery charger for boats. Also, we grouped them based on their most remarkable features. 

Types of solar battery charger for boat

There are three basic types of solar battery chargers. Inasmuch as the goal is the same, the path to achieving that goal is where they differ. They include;

  1. Float charger: Like the name suggests, they provide steady current to the battery. Once the battery is fully charged, the controller cuts off power and goes into float. Charging resumes automatically when the battery voltage drops. 
  2. Trickle charger: They supply very low current that is just enough to maintain the charge of the battery but will not charge the battery full. 
  3. Boost charger: This type of solar battery chargers is used to jumpstart a drained battery. They supply a short burst of high currents that should fully charge the battery within a short time. 

Review of the Best Solar Battery Charger for Boat

From cell phones to GPS, and fish finders, there are numerous electronic devices that need constant power throughout your boating adventure. Staying confined close to the wall socket at home because of low power is bad enough. Running out of battery in the middle of the sea or ocean is even worse. However, the best solar battery charger for boats does not only help to prevent the battery from draining when the boat is not in use, but it also helps to extend the use of a battery. Without further chitchats, here is our list.

ECO-Worthy Portable Power Backup Kit – Best overall

Key Features

  • Cigarette lighter adapter
  • Inbuilt blocking diode
  • Wattage: 10 watts
  • Weight: 1.46 pounds

The lightweight, low price, and unique design of the ECO-Worthy portable power backup kit will make you fall in love with the product at a first glance. However, the usefulness goes far beyond aesthetics. Modern boats have lots of control modules that are constantly draining the battery. That is why if you keep your boat for about a month, the battery will be totally drained. This can cause sulphation which is the leading cause of battery failure. 

Like most solar battery chargers, this unit comes with a cigarette plug which will work if your boat has constant power when the key is out of the ignition. However, you must remove the solar panel from the boat battery when starting the boat. It is easy to install and is totally maintenance-free. Another interesting feature of this solar battery charger is the inbuilt blocking diode to prevent reverse discharge during shading. In addition to maintaining the battery lifetime, it also extends the useful life. 

While this solar battery charger may seem like every boater’s dream, it has its subtle flaws. Firstly, this doesn’t seem to work well when you place it behind the windshield as advertised. Also, charging with the cigarette charger is also not as effective as plugging it directly to the battery. However, to properly position this under the sun, you would need an alligator clip with a really long cord. Multiple reviews also suggest that it has a short life span. Perhaps, they were unlucky customers who bought faulty units because this product also has glowing reviews.

Pros

  • Comes with a blocking diode that prevents reverse charging
  • Offers alligator clip and cigarette charger options
  • Easy to install
  • Friendly price

Cons

  • Alligator clip cord is too short
  • Durability is questionable

Sunway Solar Trickle Charger – Best solar trickle charger for boat

Key Features

  • Made of amorphous silicon
  • Compatible with cigarette lighter
  • ABS plastic housing
  • IP44 waterproof rating
  • Blocking diode
  • Wattage: 1.5 watts
  • Weight: 1.4 pounds

At just 1.5 watts, you can be confident that this solar battery charger will not overcharge your battery. It comes with cigarette lighter cable and alligator clips giving you multiple use options. This charger is made with amorphous material which works well under cloudy weather. To further enhance efficiency, it is covered with ultra-clear PV glass. Also, to ensure higher durability, it is housed in ABS plastic which makes it stronger. 

Another useful feature is the built-in blocking diode that prevents reverse charging. Also, with the blue blinking LED charge indicator you can easily tell if the charger is working or not. This unit is extremely lightweight and maintenance-free. It can be mounted with suction cups at the inside of the windshield of your boat. In terms of pricing, it is also a good bargain. 

There are a couple of problems that have been reported with this product. Firstly, the waterproofing is not adequate. Therefore, you have to be cautious when placing it on your boat to make sure it is on an area free from excessive dampness. Also, the low wattage means it is more effective on smaller batteries. Perhaps, this is why many complain that it didn’t work for them. Lastly, the accompanying suction cup for mounting is laughable. Besides these, it is an amazing product to have. 

Pros

  • Amorphous silicon seems to work well in a cloudy environment
  • Supports alligator clip and cigarette lighter connections
  • Indicator LED makes it easy to tell when product is working
  • Inbuilt blocking diode prevents reverse charging
  • Affordable 

Cons

  • Poor waterproofing
  • Low wattage limits use

SOLPERK Solar Panel Kit – Best marine solar battery charger kit

Key Features

  • Adjustable mount bracket
  • Upgraded waterproof controller
  • High conversion rate (24%)
  • 12 months warranty
  • Wattage: 20 watts
  • Weight: 5.08 pounds

Charging boat batteries with solar panels is often tricky when you consider the possibility of overcharging your battery. However, you can limit that odds using a marine solar battery charger kit. The good thing about this kit is that they come with a charge controller that adds a layer of protection to your battery. The charge controller uses 3-stage charging to eliminate overcharging problems including the avoidance of short circuit, under or over voltage, and output overload.

SOLPERK solar panel is made of monocrystalline solar cells proven to have a higher conversion rate compared to other types of panels. On the backside, this unit is equipped with a flexible bracket that allows you to adjust the angle of the panel to obtain maximum sunlight. Interestingly, the bracket is easy to install on the roof or wall of your boat. Unlike other solar battery chargers, this one has great waterproof performance. The manufacturers make use of tempered glass, waterproof film, and aluminum frames to extend its outdoor use. 

This unit is compatible with all battery types including gel, AGM, EFB, and so on. However, SOLPERK solar panel has its own problems. Firstly, the lifespan of the charge controller seems short. Some say the controller died as early as 2 weeks after purchase. Also, it appears the unit was reverse-wired compared. Therefore, you will need to rewire the unit before using it. The price is slightly higher than other competing brands too. Regardless, it is a good product. 

Pros

  • Built tough to last long
  • Adjustable mounting bracket to get maximum sun exposure
  • Accompanying charge controller eliminates overcharging
  • Made of monocrystalline cells with higher efficiency

Cons

  • Slightly expensive
  • Charge controller is potentially problematic
  • Reverse wiring can lead to confusion

SUNER POWER Charger Maintainer – Best marine solar battery maintainer

Key Features

  • Compatible with deep cycle batteries
  • Inbuilt blocking diode
  • 12-month warranty
  • Lifetime technical support
  • Wattage: 8 watts
  • Weight: 2.79 pounds

This marine solar battery maintainer was voted the ‘Best Battery Maintainer in 2021’ by CNET—and this is not a fluke. Firstly, it is compatible with all battery types including Wet, Gel, SLA, AGM, and deep cycle. This solar battery charger for boats will not drain or overcharge your battery, thanks to the built-in blocking diode. To improve durability, the entire panel is covered with premium strong solar glass. Likewise, the ABS frame has been upgraded. 

Like all other premium solar battery chargers, this one can be used either with a cigarette lighter socket or with alligator battery clamps. When using a cigarette lighter, make sure it is disconnected from the socket when you want to start the engine. This unit is basically plug-and-play with little or no additional maintenance. The customer service is also fast, responsive, and always willing to resolve any customer complaint. 

If you are already thinking about buying this product, there are a few downsides you need to keep in mind. Firstly, it has no indicator light which may make it hard to tell if the unit is functional or not. There are multiple reviews with complaints that the unit either fried their battery because of excessive voltage output or the battery died because the unit was not functional. Well, the 12-month warranty, good customer service, and lifetime technical support should make up for any problem that you might encounter. 

Pros

  • Broad compatibility with different battery types
  • Lifetime customer support and a 12-month warranty
  • Responsive customer service
  • Built-in blocking diode prevents reverse charging
  • Upgraded ABS frame for better durability

Cons

  • Slightly more expensive than competitors
  • Lack of indicator lights makes it hard to tell if the unit is working
  • Effectiveness is questionable

POWOXI 7.5W Solar Battery Charger– Best waterproof solar battery charger

Key Features

  • High conversion rate (20%)
  • Inbuilt barrier diode
  • 12-month warranty
  • IP65 waterproof rating
  • Blue LED indicator
  • Wattage: 7.5 watts
  • Weight: 2.2 pounds

If you have a sailboat that will lie idle for a long time, POWOXI 7.5 watts solar battery charger will make sure that the battery remains charged. If batteries are not charged for a long time, they weaken or may die permanently. The 7.5 watts generated by this panel maintain a fully charged battery from draining as well as extend its useful life. You can connect it to the battery using the cigarette lighter plug or using the alligator clamps. 

One of the stunning features of this product is the IP65 waterproof rating. The majority of the solar battery charger for boats on the market don’t even come close to that rating. Also, the inbuilt barrier diode prevents reverse charging which can drain the battery. Another useful feature is the blue LED indicator which tells you if the unit is working or not. The panel is covered with high-efficiency PV glass for maximum protection. 

This solar battery charger works with all types of batteries including deep cycle batteries. The icing on the product is the 12-month warranty and life-long technical support. However, one common problem that has been reported often is that this puts out 18V. That means you will need a regulator or it may just overcharge and fry your battery. Also, the plastic frame tends to melt under the sun’s heat. Well, it is still a great product for the price. 

Pros

  • Affordable
  • Prevents reverse charging using inbuilt barrier diode
  • High waterproof rating
  • Blue LED indicator turns on when working
  • Works with all battery types

Cons

  • Ineffective on big batteries
  • Plastic easily deforms under heat

Battery Tender solar battery charger – Best for solar conversion efficiency

Key Features

  • Built-in 3-step microcontroller
  • Inbuilt temperature sensor
  • Weatherproof
  • Wattage: 10 watts
  • Weight: 4.6 pounds

Charging boat batteries with solar panels helps to prevent them from getting totally drained which could damage the batteries. One product that you can bank on to do the job effectively for an extended period is Battery Tender 10W solar battery charger. Arguably the most impressive feature of this panel is the inbuilt proprietary 3-step microcontroller for super-smart charging and prevention of battery damage from overcharging. 

To make sure that this solar charger doesn’t drain your battery, it comes with reverse polarity protection. Furthermore, it is spark-proof and weatherproof. Therefore, when you mount it on your boat, you never have to be worried about the charger getting damaged by water. It also comes with an inbuilt temperature compensation sensor that prevents overheating of your battery. 

These features make this great for outdoor use as well as charging and maintaining your boat tours for longer hours. Sadly, with all the cool features also comes a hefty price. If you have a slim budget, you need to consider other products. Many reviewers complained about products not working right out of the box. Also, customer support is not efficient. Finally, the product may not be as waterproof as advertised. Therefore, you need to be wary about how you mount it.

Pros

  • Helps prevent the battery from draining totally
  • Inbuilt 3-step microcontroller protects battery life
  • Offers protection from reverse polarity
  • Comes with a built-in temperature compensation sensor

Cons

  • Pricey
  • Questionable waterproofing
  • Some units don’t work out of the box

SUNER POWER Pro Solar Battery Charger – Best sailboat solar battery charger

Key Features

  • LED indicator
  • Inbuilt MPPT charge controller
  • Waterproof
  • Strong ABS frame
  • Wattage: 12 watts
  • Weight: 3.14 pounds

The most useful feature of the SUNER POWER pro is the advanced MPPT charge controller. It generates up to 20% more power than the regular controller. It uses an improved smart 3-stage charging algorithm to maintain battery all seasons. The charge controller also protects the battery from overcharging, over-voltage, and short circuit. 

The manufacturers smartly include a colorful LED indicator that tells you the working status of the solar battery charger. If the battery is fully charged, the controller automatically cuts off charging and resumes if the battery voltage drop. To ensure this unit lasts long, it comes with tempered glass and a strong ABS frame. Like many of the high-end products, Suner Power backs this one with a 12-month warranty and lifetime technical support. 

This product has an IP65 waterproof rating. This means you can leave it on your boat all season. Nevertheless, this product has its limitations and challenges too. Firstly, it has limited mounting options. The best you can do is to improvise. Also, it is more expensive than most of the competing brands. However, numerous marine solar battery charger reviews on this product are generally positive which says a lot about what you should expect. 

Pros

  • Comes with an advanced MPPT charge controller
  • LED indicator for easy monitoring 
  • High waterproof rating
  • Built tough with a strong ABS frame
  • Offers 12-month warranty with lifetime technical support

Cons

  • Slightly expensive
  • Limited mounting option

Buying Guide for the Best Solar Battery Charger for Boat

If you are shopping for a solar battery charger for boats, there are a number of things that you need to know. For example, some solar battery chargers work with specific types of batteries. There are myriads of features to look out for but we have highlighted the most important ones below. 

Battery compatibility

There are different types of batteries including AGM, Gel, and Deep cycle. You need to make sure that the solar battery charger you want to buy is compatible with your boat battery. The manufacturer should provide this information. Where it is not available, make sure you ask the customer service. 

Wattage

The bigger the battery you want to maintain, the larger the size of the solar battery charger you should go for. The wattage can range from 1.5W to 30W. You want to pair the right battery size with the right solar charger. If the charger is way bigger than the battery, you may end up overcharging your battery rather than just maintaining it. 

Blocking diode

Without a blocking diode, as soon as the sun goes down, the panel will begin to discharge your battery. It is crucial to make sure that the solar battery charger you intend to buy has a blocking diode. 

Installation

Ease of installation is another critical factor you should look out for when shopping for a solar battery charger for boats. Some products come with suction cups which you can use to install the panel behind your windshield. Determine how you want to want to mount the panel and choose a suitable product accordingly. 

LED Indicator

While this is not a vital point when making your choice, it can come in handy. LED indicators can easily tell you whether the charger is functional or not. It can also help you to detect short circuit or shading. 

Price

Solar battery chargers for boats are fairly affordable. However, there are few products that go over $100. When it comes to buying a solar battery charger there is always a huge chance that you will find a great product below $50. 

How to improve the efficiency of solar battery charger for boat

To make sure your solar battery charger continues to function optimally, there are a number of things that you need to do. They include;

Regular cleaning of the panel

Dust or snow can reduce the efficiency of your solar panel by lowering the amount of sunlight that can get through. Wiping off any dust or debris and gently cleaning the surface with a damp cloth can restore the performance of the panel to optimal levels. 

Be mindful of the weather

While some models of solar battery chargers are weatherproof, others are not. Know what your solar battery charger can handle. 

Mount in a place with proper solar exposure

While some of these chargers give you multiple mounting options including behind the windshield, exposing them to direct sun will always lead to better performance. 

Choose your charging method carefully

Solar battery chargers allow you to either connect directly to the battery using alligator clamps or connect to the cigarette socket. However, multiple marine solar battery charger reviews suggest that plugging directly into the battery is more efficient. 

Frequently Asked Questions

  • Do solar battery chargers really work?

Multiple marine solar battery charger reviews show that they really work in maintaining the battery and preventing total draining. However, you need to find the perfect match for your battery to enjoy its benefits. 

  • Can you leave a solar trickle charger on all the time?

You can leave a solar trickle charger of 2.5 watts on all the time without worrying about overcharging your battery. However, it is always advised that you disconnect them before turning on the engine of your boat. 

  • How long does it take a 1.5-watt solar panel to charge a battery?

It will depend on the size of the battery and the quality of solar radiation. However, it will take about 8 hours to charge a 12-volt boat battery with a solar panel that can generate 1 amp of current. 

  • How long does a solar charger last?

The lifespan of a solar charger is usually around 300 to 400 charges. But, it will most likely boil down to how you use and take care of it. 

Conclusion

Solar Battery Charger For Boat

Mounting of a solar battery charger for boat (Photo credit: BoatCrunch)

Ideally, people only go for a recreational boat tour on a bright sunny day. Rarely will anyone take out their boat on a cloudy, stormy day. Also, standard battery chargers are seldom waterproof. A combination of all these factors makes the use of solar boat battery chargers a sensible option. Since the batteries on personal boats are usually small, they have a higher likelihood of overload if you use regular solar chargers. Therefore, the best solar battery charger for boat tend to provide just the perfect amount of electricity to prevent battery overload. 

However, there are a number of considerations that must be made when choosing a solar battery charger—and this can make the entire selection process tough. Firstly, it is important to mention that solar chargers for boats are different from the ones made for phones and their use is often not interchangeable. We sieved through hundreds of products to find the best solar battery charger for boats. Also, we grouped them based on their most remarkable features. 

Types of solar battery charger for boat

There are three basic types of solar battery chargers. Inasmuch as the goal is the same, the path to achieving that goal is where they differ. They include;

  1. Float charger: Like the name suggests, they provide steady current to the battery. Once the battery is fully charged, the controller cuts off power and goes into float. Charging resumes automatically when the battery voltage drops. 
  2. Trickle charger: They supply very low current that is just enough to maintain the charge of the battery but will not charge the battery full. 
  3. Boost charger: This type of solar battery chargers is used to jumpstart a drained battery. They supply a short burst of high currents that should fully charge the battery within a short time. 

Review of the Best Solar Battery Charger for Boat

From cell phones to GPS, and fish finders, there are numerous electronic devices that need constant power throughout your boating adventure. Staying confined close to the wall socket at home because of low power is bad enough. Running out of battery in the middle of the sea or ocean is even worse. However, the best solar battery charger for boats does not only help to prevent the battery from draining when the boat is not in use, but it also helps to extend the use of a battery. Without further chitchats, here is our list.

ECO-Worthy Portable Power Backup Kit – Best overall

Key Features

  • Cigarette lighter adapter
  • Inbuilt blocking diode
  • Wattage: 10 watts
  • Weight: 1.46 pounds

The lightweight, low price, and unique design of the ECO-Worthy portable power backup kit will make you fall in love with the product at a first glance. However, the usefulness goes far beyond aesthetics. Modern boats have lots of control modules that are constantly draining the battery. That is why if you keep your boat for about a month, the battery will be totally drained. This can cause sulphation which is the leading cause of battery failure. 

Like most solar battery chargers, this unit comes with a cigarette plug which will work if your boat has constant power when the key is out of the ignition. However, you must remove the solar panel from the boat battery when starting the boat. It is easy to install and is totally maintenance-free. Another interesting feature of this solar battery charger is the inbuilt blocking diode to prevent reverse discharge during shading. In addition to maintaining the battery lifetime, it also extends the useful life. 

While this solar battery charger may seem like every boater’s dream, it has its subtle flaws. Firstly, this doesn’t seem to work well when you place it behind the windshield as advertised. Also, charging with the cigarette charger is also not as effective as plugging it directly to the battery. However, to properly position this under the sun, you would need an alligator clip with a really long cord. Multiple reviews also suggest that it has a short life span. Perhaps, they were unlucky customers who bought faulty units because this product also has glowing reviews.

Pros

  • Comes with a blocking diode that prevents reverse charging
  • Offers alligator clip and cigarette charger options
  • Easy to install
  • Friendly price

Cons

  • Alligator clip cord is too short
  • Durability is questionable

Sunway Solar Trickle Charger – Best solar trickle charger for boat

Key Features

  • Made of amorphous silicon
  • Compatible with cigarette lighter
  • ABS plastic housing
  • IP44 waterproof rating
  • Blocking diode
  • Wattage: 1.5 watts
  • Weight: 1.4 pounds

At just 1.5 watts, you can be confident that this solar battery charger will not overcharge your battery. It comes with cigarette lighter cable and alligator clips giving you multiple use options. This charger is made with amorphous material which works well under cloudy weather. To further enhance efficiency, it is covered with ultra-clear PV glass. Also, to ensure higher durability, it is housed in ABS plastic which makes it stronger. 

Another useful feature is the built-in blocking diode that prevents reverse charging. Also, with the blue blinking LED charge indicator you can easily tell if the charger is working or not. This unit is extremely lightweight and maintenance-free. It can be mounted with suction cups at the inside of the windshield of your boat. In terms of pricing, it is also a good bargain. 

There are a couple of problems that have been reported with this product. Firstly, the waterproofing is not adequate. Therefore, you have to be cautious when placing it on your boat to make sure it is on an area free from excessive dampness. Also, the low wattage means it is more effective on smaller batteries. Perhaps, this is why many complain that it didn’t work for them. Lastly, the accompanying suction cup for mounting is laughable. Besides these, it is an amazing product to have. 

Pros

  • Amorphous silicon seems to work well in a cloudy environment
  • Supports alligator clip and cigarette lighter connections
  • Indicator LED makes it easy to tell when product is working
  • Inbuilt blocking diode prevents reverse charging
  • Affordable 

Cons

  • Poor waterproofing
  • Low wattage limits use

SOLPERK Solar Panel Kit – Best marine solar battery charger kit

Key Features

  • Adjustable mount bracket
  • Upgraded waterproof controller
  • High conversion rate (24%)
  • 12 months warranty
  • Wattage: 20 watts
  • Weight: 5.08 pounds

Charging boat batteries with solar panels is often tricky when you consider the possibility of overcharging your battery. However, you can limit that odds using a marine solar battery charger kit. The good thing about this kit is that they come with a charge controller that adds a layer of protection to your battery. The charge controller uses 3-stage charging to eliminate overcharging problems including the avoidance of short circuit, under or over voltage, and output overload.

SOLPERK solar panel is made of monocrystalline solar cells proven to have a higher conversion rate compared to other types of panels. On the backside, this unit is equipped with a flexible bracket that allows you to adjust the angle of the panel to obtain maximum sunlight. Interestingly, the bracket is easy to install on the roof or wall of your boat. Unlike other solar battery chargers, this one has great waterproof performance. The manufacturers make use of tempered glass, waterproof film, and aluminum frames to extend its outdoor use. 

This unit is compatible with all battery types including gel, AGM, EFB, and so on. However, SOLPERK solar panel has its own problems. Firstly, the lifespan of the charge controller seems short. Some say the controller died as early as 2 weeks after purchase. Also, it appears the unit was reverse-wired compared. Therefore, you will need to rewire the unit before using it. The price is slightly higher than other competing brands too. Regardless, it is a good product. 

Pros

  • Built tough to last long
  • Adjustable mounting bracket to get maximum sun exposure
  • Accompanying charge controller eliminates overcharging
  • Made of monocrystalline cells with higher efficiency

Cons

  • Slightly expensive
  • Charge controller is potentially problematic
  • Reverse wiring can lead to confusion

SUNER POWER Charger Maintainer – Best marine solar battery maintainer

Key Features

  • Compatible with deep cycle batteries
  • Inbuilt blocking diode
  • 12-month warranty
  • Lifetime technical support
  • Wattage: 8 watts
  • Weight: 2.79 pounds

This marine solar battery maintainer was voted the ‘Best Battery Maintainer in 2021’ by CNET—and this is not a fluke. Firstly, it is compatible with all battery types including Wet, Gel, SLA, AGM, and deep cycle. This solar battery charger for boats will not drain or overcharge your battery, thanks to the built-in blocking diode. To improve durability, the entire panel is covered with premium strong solar glass. Likewise, the ABS frame has been upgraded. 

Like all other premium solar battery chargers, this one can be used either with a cigarette lighter socket or with alligator battery clamps. When using a cigarette lighter, make sure it is disconnected from the socket when you want to start the engine. This unit is basically plug-and-play with little or no additional maintenance. The customer service is also fast, responsive, and always willing to resolve any customer complaint. 

If you are already thinking about buying this product, there are a few downsides you need to keep in mind. Firstly, it has no indicator light which may make it hard to tell if the unit is functional or not. There are multiple reviews with complaints that the unit either fried their battery because of excessive voltage output or the battery died because the unit was not functional. Well, the 12-month warranty, good customer service, and lifetime technical support should make up for any problem that you might encounter. 

Pros

  • Broad compatibility with different battery types
  • Lifetime customer support and a 12-month warranty
  • Responsive customer service
  • Built-in blocking diode prevents reverse charging
  • Upgraded ABS frame for better durability

Cons

  • Slightly more expensive than competitors
  • Lack of indicator lights makes it hard to tell if the unit is working
  • Effectiveness is questionable

POWOXI 7.5W Solar Battery Charger– Best waterproof solar battery charger

Key Features

  • High conversion rate (20%)
  • Inbuilt barrier diode
  • 12-month warranty
  • IP65 waterproof rating
  • Blue LED indicator
  • Wattage: 7.5 watts
  • Weight: 2.2 pounds

If you have a sailboat that will lie idle for a long time, POWOXI 7.5 watts solar battery charger will make sure that the battery remains charged. If batteries are not charged for a long time, they weaken or may die permanently. The 7.5 watts generated by this panel maintain a fully charged battery from draining as well as extend its useful life. You can connect it to the battery using the cigarette lighter plug or using the alligator clamps. 

One of the stunning features of this product is the IP65 waterproof rating. The majority of the solar battery charger for boats on the market don’t even come close to that rating. Also, the inbuilt barrier diode prevents reverse charging which can drain the battery. Another useful feature is the blue LED indicator which tells you if the unit is working or not. The panel is covered with high-efficiency PV glass for maximum protection. 

This solar battery charger works with all types of batteries including deep cycle batteries. The icing on the product is the 12-month warranty and life-long technical support. However, one common problem that has been reported often is that this puts out 18V. That means you will need a regulator or it may just overcharge and fry your battery. Also, the plastic frame tends to melt under the sun’s heat. Well, it is still a great product for the price. 

Pros

  • Affordable
  • Prevents reverse charging using inbuilt barrier diode
  • High waterproof rating
  • Blue LED indicator turns on when working
  • Works with all battery types

Cons

  • Ineffective on big batteries
  • Plastic easily deforms under heat

Battery Tender solar battery charger – Best for solar conversion efficiency

Key Features

  • Built-in 3-step microcontroller
  • Inbuilt temperature sensor
  • Weatherproof
  • Wattage: 10 watts
  • Weight: 4.6 pounds

Charging boat batteries with solar panels helps to prevent them from getting totally drained which could damage the batteries. One product that you can bank on to do the job effectively for an extended period is Battery Tender 10W solar battery charger. Arguably the most impressive feature of this panel is the inbuilt proprietary 3-step microcontroller for super-smart charging and prevention of battery damage from overcharging. 

To make sure that this solar charger doesn’t drain your battery, it comes with reverse polarity protection. Furthermore, it is spark-proof and weatherproof. Therefore, when you mount it on your boat, you never have to be worried about the charger getting damaged by water. It also comes with an inbuilt temperature compensation sensor that prevents overheating of your battery. 

These features make this great for outdoor use as well as charging and maintaining your boat tours for longer hours. Sadly, with all the cool features also comes a hefty price. If you have a slim budget, you need to consider other products. Many reviewers complained about products not working right out of the box. Also, customer support is not efficient. Finally, the product may not be as waterproof as advertised. Therefore, you need to be wary about how you mount it.

Pros

  • Helps prevent the battery from draining totally
  • Inbuilt 3-step microcontroller protects battery life
  • Offers protection from reverse polarity
  • Comes with a built-in temperature compensation sensor

Cons

  • Pricey
  • Questionable waterproofing
  • Some units don’t work out of the box

SUNER POWER Pro Solar Battery Charger – Best sailboat solar battery charger

Key Features

  • LED indicator
  • Inbuilt MPPT charge controller
  • Waterproof
  • Strong ABS frame
  • Wattage: 12 watts
  • Weight: 3.14 pounds

The most useful feature of the SUNER POWER pro is the advanced MPPT charge controller. It generates up to 20% more power than the regular controller. It uses an improved smart 3-stage charging algorithm to maintain battery all seasons. The charge controller also protects the battery from overcharging, over-voltage, and short circuit. 

The manufacturers smartly include a colorful LED indicator that tells you the working status of the solar battery charger. If the battery is fully charged, the controller automatically cuts off charging and resumes if the battery voltage drop. To ensure this unit lasts long, it comes with tempered glass and a strong ABS frame. Like many of the high-end products, Suner Power backs this one with a 12-month warranty and lifetime technical support. 

This product has an IP65 waterproof rating. This means you can leave it on your boat all season. Nevertheless, this product has its limitations and challenges too. Firstly, it has limited mounting options. The best you can do is to improvise. Also, it is more expensive than most of the competing brands. However, numerous marine solar battery charger reviews on this product are generally positive which says a lot about what you should expect. 

Pros

  • Comes with an advanced MPPT charge controller
  • LED indicator for easy monitoring 
  • High waterproof rating
  • Built tough with a strong ABS frame
  • Offers 12-month warranty with lifetime technical support

Cons

  • Slightly expensive
  • Limited mounting option

Buying Guide for the Best Solar Battery Charger for Boat

If you are shopping for a solar battery charger for boats, there are a number of things that you need to know. For example, some solar battery chargers work with specific types of batteries. There are myriads of features to look out for but we have highlighted the most important ones below. 

Battery compatibility

There are different types of batteries including AGM, Gel, and Deep cycle. You need to make sure that the solar battery charger you want to buy is compatible with your boat battery. The manufacturer should provide this information. Where it is not available, make sure you ask the customer service. 

Wattage

The bigger the battery you want to maintain, the larger the size of the solar battery charger you should go for. The wattage can range from 1.5W to 30W. You want to pair the right battery size with the right solar charger. If the charger is way bigger than the battery, you may end up overcharging your battery rather than just maintaining it. 

Blocking diode

Without a blocking diode, as soon as the sun goes down, the panel will begin to discharge your battery. It is crucial to make sure that the solar battery charger you intend to buy has a blocking diode. 

Installation

Ease of installation is another critical factor you should look out for when shopping for a solar battery charger for boats. Some products come with suction cups which you can use to install the panel behind your windshield. Determine how you want to want to mount the panel and choose a suitable product accordingly. 

LED Indicator

While this is not a vital point when making your choice, it can come in handy. LED indicators can easily tell you whether the charger is functional or not. It can also help you to detect short circuit or shading. 

Price

Solar battery chargers for boats are fairly affordable. However, there are few products that go over $100. When it comes to buying a solar battery charger there is always a huge chance that you will find a great product below $50. 

How to improve the efficiency of solar battery charger for boat

To make sure your solar battery charger continues to function optimally, there are a number of things that you need to do. They include;

Regular cleaning of the panel

Dust or snow can reduce the efficiency of your solar panel by lowering the amount of sunlight that can get through. Wiping off any dust or debris and gently cleaning the surface with a damp cloth can restore the performance of the panel to optimal levels. 

Be mindful of the weather

While some models of solar battery chargers are weatherproof, others are not. Know what your solar battery charger can handle. 

Mount in a place with proper solar exposure

While some of these chargers give you multiple mounting options including behind the windshield, exposing them to direct sun will always lead to better performance. 

Choose your charging method carefully

Solar battery chargers allow you to either connect directly to the battery using alligator clamps or connect to the cigarette socket. However, multiple marine solar battery charger reviews suggest that plugging directly into the battery is more efficient. 

Frequently Asked Questions

  • Do solar battery chargers really work?

Multiple marine solar battery charger reviews show that they really work in maintaining the battery and preventing total draining. However, you need to find the perfect match for your battery to enjoy its benefits. 

  • Can you leave a solar trickle charger on all the time?

You can leave a solar trickle charger of 2.5 watts on all the time without worrying about overcharging your battery. However, it is always advised that you disconnect them before turning on the engine of your boat. 

  • How long does it take a 1.5-watt solar panel to charge a battery?

It will depend on the size of the battery and the quality of solar radiation. However, it will take about 8 hours to charge a 12-volt boat battery with a solar panel that can generate 1 amp of current. 

  • How long does a solar charger last?

The lifespan of a solar charger is usually around 300 to 400 charges. But, it will most likely boil down to how you use and take care of it. 

Conclusion

It is important to mention that a solar battery charger can overcharge your battery if you make the wrong choice. However, you can avoid this ugly scenario by choosing a product with a solar charge controller. The controller monitors the health of the battery and cuts off the power once the battery is fully charged. Nevertheless, you will never have to worry about that if you follow all the instructions provided in our buying guide. 

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