Marine Battery Chargers

Should you need an onboard battery charger that has multiple banks, you’ve got a pretty serious battery setup that likely contains a house battery, a battery that is starting, a trolling motor battery, plus much more. A multiple bank onboard battery charger can save a great deal of time and frustration within rotating a one or two charge battery charger one of batteries or bringing a battery charger onto your boat each time that your batteries need recharging.

You are also being smart as selecting a multi-bank onboard battery charger over rotatingshaft, or attempting to charge multiple batteries simultaneously with one charger, permits you to apply all of the benefits of a contemporary charger maintainer to every battery according to its needs. This is likely to prolong the life span of each battery and help you save money in the long term.

Now’s onboard multiple-bank chargers are smart chargers with built-in microprocessors to restrain their multi-phase charging and maintenance processes and might also include desulfation and regain functions. They could provide better battery performance and longer lifetime. They’re also very likely to permit you to maintain all of your batteries throughout the off-season unattended automatically so that your boat is ready when you are in the Spring.

What should you look for in a multi-bank onboard battery charger?


How much electricity do you want? The output you desire from a multi-bank system is closely related to the use of every battery. Here’s a Fast guide to amperage output for some applications:

O Low Output – (6 amps below) A low output model may be applicable for maintenance use or any minimal amp hour battery program.

O Medium Output – (9 – 15 amps) A moderate output model would be appropriate for medium use or occasional use perhaps only on weekends for a trolling motor.

O High Output – (15 amps or above) A top output model could be used in large amp hour battery applications (150 Ah such as), or some other scenario where repeated rapid recharging is required.

Be careful when deciding on the amperage output according to its description. Vendors and manufacturers typically publish amperage in two ways. One means is to print the overall amps by assessing the output of every bank times the number of banks. For instance, they may publish the output as 40 Amps, however what they are really telling you is the charger generates 10 Amps output for each lender. Another way and more useful would be to publish the output per lender.

A common rapid calculation to find out how much amperage output you need is to ascertain the amp-hour rating of every MXJO 18650 Battery and add them together. Then multiply that amount by 10% to find the amperage needed. In the case of four 105 amp-hour batteries, you’d need approximately 10 percent of 420 amp-hours or 42 amps or approximately 10 amps each bank for a 4-bank battery charger.

Battery Voltage

Most marine systems are all based on 12V or 24V batteries. Be sure the onboard battery charging system you choose can take care of your ship’s battery voltages.

Battery Types

Marine batteries serve various purposes on-board your ship which range from beginning to supplying electricity for all the principal systems.

Gel Cel batteries take a unique charging profile that can only be provided by models especially designed to charge Gel cel batteries. Onboard battery chargers that control AGM or deep cycle batteries aren’t equipped to properly charge Gel Cel batteries. Ensure you opt for a marine version that could handle all of the battery types you’ve got.

Smart Chargers

Most contemporary multi-bank onboard system have integrated microprocessors. These computers run intelligent programs to control and keep your batteries unattended without repainting or damaging your batteries, charger or boat systems.

Many include built-in security features that protect against reverse polarity and can also monitor battery charging status, battery state, and adjust charger output to match the needs of every individual battery.

The marine environment is one filled with moisture such as direct spray and humidity. Though your model may not be subjected to direct spray, any charger that you’re considering should be completely sealed, waterproof, and capable of withstanding the harsh marine environment.

Based on where you’re planning to mount the onboard system, it might be subjected to everything from salt spray to even heavier splashes of fresh or sea water. In any case, you can count on an unrelenting attack by corrosion.


Almost always, when a battery charger is distinguished as an onboard version, it will include the ability to be mounted and contain associated hardware. Mounting your battery charger is going to result in a neater installation that reduces the risk of damage to the battery charger or its cabling.

It’s worth mentioning that it may not necessarily be true, so it is worthwhile to check for included components and mounting brackets if you are considering mounting it onto a bulkhead.


Boats that feature enclosed engine pockets may collect fumes out of both batteries and fuel and should not properly ventilated pose a potential explosion and fire risk. Any onboard battery charger you choose should comply with ISO 8846 along with U.S. Coast Guard Title 33 CFR 183.410 ignition protection specifications that says that compliant devices:

O will not ignite a flammable hydrocarbon mixture surrounding the apparatus once and ignition source causes an internal explosion

O or the source of the ignition is hermetically sealed.

Also search for other safety features such as protection against over-voltage, overload, over-temperature, and reverse polarity.

Power Inverter

Some mutli-bank battery chargers have incorporated AC outlets to support additional onboard AC devices near the charger. If that is an ability you need, assess for that attribute.