If you have a medium to large boat, chances are you have multiple batteries on that boat. Or maybe you have several small fishing boats with a trolling motor battery on each one.
Regardless of the circumstances, you need a way to charge multiple batteries at one time. Wouldn’t it be great if there was a marine battery charger that could charge two, three, or four marine batteries at once?
Guess what? There is!
In fact, 2, 3, and 4-bank chargers have become increasingly popular over time, and you have a variety of brands and options to choose from.
So, how can you know which brands and which specific chargers are best?
In this article, we’ll review and discuss the 5 best two-, three-, and four-bank marine battery chargers on the market.
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Table of Contents
- Marine Battery Charger Reviews
- Marine Battery Bank Buyer’s Guide
Marine Battery Charger Reviews
1. Best Two-Bank Charger: NOCO Genius GEN5X2
- Meet the GEN5X2 - Similar to our GENM2, only better. It's 37% smaller and delivers 43% more power. It's one of the best performing onboard marine battery chargers we have ever made.
- Multiple banks - A two-bank onboard battery charger rated a 10-amps - 5-amps per bank - for 12-volt batteries, including marine, boat, starter, and deep-cycle batteries.
This two-bank charger comes from NOCO Genius, a well-known brand for marine battery chargers. It is a high-quality charger, maintainer, and desulfator that has received excellent customer reviews and is considered a top seller among battery chargers.
This charger produces a total output of 10 amps, which is 5 amps per bank. It will charge all types of 12V marine batteries, including lithium. It charges automatically down to 1 volt but can also be used manually to charge batteries that are completely dead.
This charger is completely waterproof and can be mounted in any position on your boat. It weighs just under 5 ½ pounds, so it won’t add a great amount of weight or take up a lot of space.
This charger is an excellent choice for anyone with two 12V batteries on their boat or anyone who normally has one battery on board but who sometimes needs the option of charging up a second battery.
Some of this charger’s key features include its built-in thermal sensor, which adjusts charging output based on the ambient temperature to avoid over and under-charging; and its auto-repair function, which can repair and even reverse some types of battery damage.
Some customers have noted that this charger may have only one working bank, or that one bank goes bad after a short period of use.
There is a 30-day return window, so you may want to use this charger frequently within the first month to determine whether you’ll need to request a replacement.
What we like
- This charger works for all types of marine batteries.
- It works automatically but will manually charge even dead batteries.
- The thermal sensor prevents over and under-charging.
What we don’t like
- Sometimes one battery bank fails prematurely.
2. Best Three-Bank Charger: NOCO Genius GEN5X3
- Meet the GEN5X3 - Similar to our GENM3, only better. It's 37% smaller and delivers 43% more power. It's one of the best performing onboard marine battery chargers we have ever made.
- Multiple banks - A three-bank onboard battery charger rated a 15-amps - 5-amps per bank - for 12-volt batteries, including marine, boat, starter, and deep-cycle batteries.
This three-bank charger, also from NOCO Genius, is in many ways identical to the two-bank charger reviewed above. It boasts the same high-quality design and is extremely popular among customers who need to charge extra marine batteries at once.
Like the two-bank charger above, this charger can produce an output of up to 5 amps per bank, giving the charger an overall output capacity of 15 amps. It will charge all types of marine batteries and has different settings for specific types.
It weighs just over 6 pounds, so it won’t add a considerable amount of weight to your boat. It is completely waterproof, and you can mount it anywhere on your boat in any position that is most convenient.
It charges automatically as long as your batteries are above 1 volt, but it can also be used manually to charge completely dead batteries as low as 0 volts.
This charger is a great choice for anyone with up to three batteries on their boat. It will also work for you if you usually have fewer batteries but sometimes need the capacity to charge up to three at a time.
Some of the battery’s key features include the built-in thermal sensor, which detects the air temperature and adjusts the charge flow accordingly to prevent over- and under-charging; and its auto-repair function that can detect and repair certain types of damage to the battery.
Some customers have noted that this charger has no quick disconnect option–it is meant to be permanently connected to your batteries. If you plan to remove your batteries between boating trips or if you don’t have them permanently mounted, keep this in mind.
What we like
- This charger will charge all types of marine batteries.
- You can use it to charge dead batteries manually.
- The thermal sensor protects your batteries from over and under-charging.
What we don’t like
- This charger has no quick disconnect function.
3. Best Four-Bank Charger: NOCO Genius GENPRO10X4
- Meet the GENPRO10X4 - Similar to our GEN4, only better. It's 10% smaller and delivers 33% more power. It's one of the best performing onboard marine battery chargers we have ever made.
- Multiple banks - A four-bank onboard battery charger rated a 40-amps - 10-amps per bank - for 12-volt batteries, including marine, boat, starter, and deep-cycle batteries.
This four-bank charger also comes from NOCO Genius, but as we’ll see in this review, it has a few differences from the brand’s two- and three-bank chargers discussed above. It is still a top-quality charger with overwhelmingly positive customer reviews.
This charger is much more powerful than the two reviewed above. It can charge up to four batteries at once and has a total output capacity of 40 amps, or 10 amps per bank. It can charge all types of marine batteries: lead-acid, AGM, gel, and lithium.
This charger is significantly heavier than the two above, weighing almost 17 pounds. That said, if you have four batteries on your boat, then your boat is undoubtedly large enough to support this extra weight relatively easily.
You can mount this charger anywhere on your boat and in any position. Its anti-shock backing protects it from the usual shocks and vibrations experienced on a boat.
Like the other NOCO Genius chargers, this one will charge automatically down to 1 volt and can be used manually to charge batteries as low as 0 volts.
This is an excellent charger for anyone with four batteries on their boat. Alternatively, it’s a good choice even if you don’t have four batteries on your boat now but would like to have the capacity to charge up to four batteries in the future.
Like the other NOCO Genius chargers above, this charger’s key features include its thermal sensor, which protects against over- and under-charging based on the air temperature; and its auto-repair function, which helps to repair some types of battery damage.
Some customers state that the charging indicator lights are not always accurate. The lights sometimes show that the batteries are more fully charged than they actually are.
What we like
- This charger has a maximum capacity of up to 10 amps per bank.
- It can charge fully dead batteries as low as 0 volts.
- The thermal sensor protects against over- and under-charging.
What we don’t like
- The indicator lights don’t always give accurate readings.
4. Best Budget Option: Extreme Max Four-Bank Charger/ Maintainer
- Allows simultaneous charge of up to four 12-volt lead-acid batteries - Each cord set measures 4' 10" in length for maximum efficiency and range
- 12V, 2A per charging bank
This charger comes from Extreme Max, a quality brand in the world of outdoor gear and tools. The charger is not made for marine battery use specifically, but it will charge some types of marine batteries and is an excellent choice if you’re on a budget.
This charger is made for 12V lead-acid batteries specifically. It will charge up to four of these batteries at a time. The charger regulates the flow of the charge so that each battery is properly recharged without becoming overcharged.
This charger provides a slower charge than the ones reviewed above, as it produces only 2 amps per battery bank. That said, this is enough to both slowly recharge batteries and maintain them at the proper storage charge level.
This charger is not meant to be mounted onto your boat, as it is not waterproof. That said, it can be used outside during dry weather.
This is the perfect charger for anyone who removes their batteries from the boat for recharging. It’s also a good choice for anyone who needs a way to maintain their batteries through the winter.
Some of this battery’s key features include its LED indicator lights, which let you know how close your batteries are to be fully recharged, and a 1-year limited warranty.
Some customers state that the charger is not as high-quality as it could be, in that it doesn’t last very long and one or more of the banks stop working. However, most customers agree that this is a good buy for the price.
What we like
- This battery charger comes with a warranty.
- It is inexpensive for a four-bank battery charger.
- It works both as a charger and a maintainer.
What we don’t like
- This charger only works for lead-acid batteries and is not waterproof.
5. Best Overall: Minn Kota Precision Onboard Charger
- Waterproof, shock and vibration resistant aluminum construction;Battery Equalization : Yes
- Saltwater test, fully corrosion-resistant construction. Product Weight: 10 lbs.; Product Dimensions: 9.25" x 10.5" x 3"
And finally, this charger comes from the well-known Minn Kota brand. Minn Kota is known for creating top-quality products, and this charger is no exception. In fact, it is one of the best multi-bank marine battery chargers on the market.
This charger comes in one-, two-, three-, and 4-bank options so you can choose the one that best fits your needs. You can also choose from the available amp output options: 6, 10, or 15 amps per bank.
This charger is designed for use with 12V batteries, and it will charge any type of marine battery except lithium. It is fully waterproof and corrosion-resistant, making it a good onboard charger for those who frequently fish in saltwater.
This charger comes with many excellent features, including a color-coded LED indicator to let you know how your batteries are doing; and automatic multi-stage charging, which produces a different charge level depending on how fully charged the batteries are.
It also has a low-line voltage compensation feature, which ensures your batteries charge quickly and efficiently no matter what. This charger comes with a 3-year replacement warranty.
Some customers have claimed that this charger tends to overcharge batteries, so you might want to pay attention while your batteries are charging, especially toward the end of the charge cycle.
What we like
- This charger comes in many different options–choose the best one for you.
- It comes with a 3-year replacement warranty.
- It comes with several useful features.
What we don’t like
- It doesn’t work for lithium batteries.
Marine Battery Bank Buyer’s Guide
Now that we’ve reviewed some of the top multi-bank marine battery chargers on the market, you may be wondering how to choose the best one for you. How can you narrow it down from five products to one product?
In this section, we’ll take a look at some important factors to consider when choosing your marine battery charger. Using this buyer’s guide, you’ll be able to determine what’s important to you and ensure you choose the best product for your specific needs.
Number of Banks
The first thing to consider is how many charging banks you want or need. Obviously, there’s no reason to spend top dollar on a four-bank charger if you only have two batteries that you need to charge from time to time.
If you have a large boat with one battery to back up your outboard motor, one to run your lights, one hooked up to your fishfinder, and one to power miscellaneous other electrical systems, then you’ll want to choose a charger with four charging banks.
If, on the other hand, you have a small fishing boat with just one battery to power your trolling motor and perhaps another battery to serve as a backup, then the most you’ll need is a two-bank charger.
That said, it’s okay to choose a charger with one bank more than you’ll regularly use. You never know when you may need to charge an extra battery, and getting a charger with an extra bank will also save you trouble should one of the charging banks fail prematurely.
The next consideration is how many amps the charger puts out. The higher the amperage per bank, then the quicker your batteries will recharge.
For example, the NOCO Genius four-bank charger reviewed above will recharge a given battery twice as quickly as the same brand’s two- and three-bank chargers. This is because the four-bank charger has an output of 10 amps per bank, while the others only produce 5 amps.
A higher amp output will not only get the job done more quickly, but it will also be more efficient for larger batteries or batteries that have been more fully discharged.
That said, for small batteries or those with a lower amp-hour rating, higher-amp chargers may get the job done too quickly. Though most chargers and many batteries have ways of safely regulating charge flow, chargers that are too powerful may cook smaller-capacity batteries.
Make sure and do your research beforehand to find out the proper amp output for your specific battery. Most of the chargers in this article have an output of 2 to 5 amps, which works well for most batteries.
Onboard or Not
Some chargers are meant to be mounted on the boat; these are known as onboard chargers. They are typically tough and waterproof, able to handle a variety of shocks and vibrations and extreme weather conditions.
Other chargers are not meant for outdoor use; these are designed to remain in the garage or in a more sheltered outdoor area. With this type of charger, you will have to remove your batteries from the boat and bring them to the charger each time they need recharging.
Depending on the type of boat and the number of batteries you have, it may make the most sense to leave them on the boat permanently, hooked up to your onboard charger between uses.
On the other hand, if you have a small boat with only one or two batteries, it may make more sense to remove them and store them in a safe place between uses. In this case, an off-board charger may make more sense for you.
All of the chargers reviewed above are onboard chargers except for the Extreme Max charger; keep this in mind as you do your shopping.
Battery Type Supported
Not all chargers will charge all battery types. It is extremely important to make sure you choose the right type of charger for the type of battery you have–especially if you have a lithium battery, which often takes a specialized type of charger.
Most of the chargers reviewed above charge multiple battery types. You can simply change the battery type setting on your charger so it will produce the proper charge for your specific type of battery.
Last but not least, it’s important to consider the weight of the charger, especially if it’s an onboard charger and you have a small boat.
The amount of weight you’re hauling impacts how well the boat handles with any type of boat. With smaller boats in particular, even a small change in the overall weight of the boat’s cargo can make significant differences in how the boat gets around in the water.
If you have a small boat with only one or two batteries, then there’s no need to add the weight of a heavy four-bank charger. But, if you have a large boat with four or more batteries on board, then the extra weight of the same charger may prove negligible.
We’ve chosen the Minn Kota Precision battery charger as the best overall because it is versatile, high-quality, and comes from a well-established brand. However, if you’re looking for a cheaper option, the Extreme Max charger has you covered.
Hopefully, after reading this article, you’ll have a better grasp on multi-bank marine battery chargers and will be able to make an informed decision about which charger will work best for you.