How To Choose And Install a High-Performing Boat Battery Charger?

An onboard charger will improve the battery performance and life. Maintaining the batteries of your boat is vital as it affects both the performance and increases service life. However, you may have a hard time keeping them charged, especially for those vessels that have limited or sporadic use.

The best way to monitor and promote your battery’s health is by installing a modern and smart charger for your battery. By how does one select the right charger for their boat’s battery. And the battle does not end there. It would be best if you learned how to choose and install a high-performing boat battery charger appropriately. Read on to find out.

What Is a High-Performing Boat Battery Charger?

The marine-grade batteries are on the expensive side, and these can be easily destroyed by improper charging. You do not want to incur the extra costs; that’s why you must avoid skimping during the charger selection. And know this, you must always select the quality marine-grade units built to American Boat& Yacht Council (ABYC) and UL standards.

Thankfully, there are smart High-Performing Boat Battery Charger options in the market today that deliver numerous charging options and features like the ability to select between the different battery technology types; gel, wet cell, absorbed glass mat AGM, and so on.

Unlike the old resonance chargers available in the past, modern chargers come fully potted. That means that their electronics have been completely encapsulated in resin, making the entire unit waterproof and reducing corrosion chances a great deal. You can use the waterproof chargers on any craft. They are still made exclusively for the installations and aboard boats, which are often naturally wet, like personal watercraft and small fishing boats.

Since uncontrolled combustion is not what we want, you must label the battery chargers installed in boats powered by gasoline as ignition-protected. They should conform to the appropriate UL specifications that include testing in an explosive environment.

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How Can I Choose a High-Performing Battery Charger?

As earlier mentioned, you must find the right charger for your boat battery or risk spending a lot on replacing the battery. Regardless of the high performing boat battery charger that you ultimately choose, steer clear of the el cheapo automotive chargers. These are not made exclusively for marine use and could cause you many problems, from shock hazards to stray current corrosion.

When it comes to the output and size, ensure that you refer to the manufacturer’s instructions when selecting a charger. The rule of thumb is choosing a charger with an output of at least 10% of the battery capacity or your boat’s battery bank. For instance, a 300 Ah bank or battery will require a 30-amp charger.

How Do I Install a High-Performing Boat Battery Charger?


When you figure out where you will mount a high performing boat battery charger, it is an exercise in compromise, so it would be best to follow all the given manufacturers’ instructions for selecting a mounting location.

The best option is usually a cool and dry area that has adequate ventilation. Generally, a higher place is more preferred than a lower one as the high spot will typically provide better ventilation and protection from the bilge’s corrosive humidity.

Moreover, you are advised to avoid high-temperature locations like the engine compartment if you can. However, the smaller boats have limited location options, so doing so may not be possible. You could also install the charger in the cockpit locker or deck, but ensure it is as high as possible in a dry corner that is away from the hatch so you can reduce exposure to water spray and drips.

Most of the boat battery charger installation areas have limited ventilation at best. If that is what you have decided for your installation, ensure that you let the charger breathe easier by not wrapping it with boat covers, life jackets, and other air-blocking items. Additional locker vents will go a long way in increasing the airflow.

It would be best if the chargers are installed practically close to the battery. Shorter leads will translate to fewer voltage drops, fewer installation costs, and increased charger performance over the unit’s life. With that being said, do not mount the charger directly over the bank or battery. The batteries, especially the wet cell or liquid electrolyte types, can produce some corrosive gases like sulfur dioxide as they charge.

These gases could quickly and easily destroy the charger of the charger is directly over them. Charging lead-acid batteries produce hydrogen gas, which may not be toxic but is highly explosive at high concentrations. This is another reason why you should ignition protect the charger and install it in a well-ventilated area.

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When you have selected a suitable spot, it is time to mount the charger itself. Smaller boat battery chargers should be mounted on a thick bulkhead or structures with screws. If the charger weighs more pounds, you should thoroughly bolt it with suitable-sized bolts, washers, and nuts. Ensure you use stainless-steel for all the mounting hardware regardless of the mounting option.

How Can I Choose And Install a High-Performing Boat Battery Charger?

Getting Wired

Charger connection will involve the installation of both AC and DC wiring. The DC wiring sizing must go according to the manufacturer’s recommendations while basing it on your battery’s distance and its charger. This measurement is a round-trip length that is the full-length of the positive and negative wires added together.

Generally, the longer the wires run, the larger the wire diameter needed to offset loss resulting from voltage drop. When you use smaller diameter wires, it could call for a decrease in charge voltage and even slow the charge rate before the battery is fully charged. This increases the time used for charging or even prevents the battery from getting fully charged.

The wire runs are to be routed directly and given the needed chafe protection and support. What’s more, you must make the DC wiring connections from marine-grade, waterproof ring terminals, or they can be butt connections. The battery charger types have a short length of the heat shrink tubing, which protects the termination once the heat shrink is activated and the connector is crimped.

In case a wire-to-wire connection is needed, use the butt splice or connector. It would be best if you never made connections using the residential electrical tapes or wire nuts as these eventually fall off due to age or vibration.

Anytime you make a connection from the charging cable to the battery post, use the closed barrel terminals and seal each with a small length of heat shrink for protection against corrosion. It would be best if you placed the charge cable terminals above the primary cable battery terminals. This makes it easy for you to monitor the terminals for corrosion and prevents spilled electrolyte from wicking up the wire.

If the DC wire of the charger terminates in alligator clamps or spring clamps, you can cut them off and replace them with ideal marine-grade ring terminals. And finally, you should coat or spray all the wire connections using a proper corrosion inhibitor to give them additional protection.

If your boat comes with a pre-installed AC system, you must plug the charger into any convenient outlet if nearby. Alternatively, you can power it from the main AC distribution panel.

It would be best if you practiced safe wiring by ensuring you unplug the AC shore power cord at the dock, the main AC circuit breaker is off, and all AC power sources are out and disconnected before starting any work. And to wire safely, ensure you start from the AC side toward the battery.

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Firing It Up

With all the connections made, and the AC power turned off, you can make the final charger connections to the battery and then verify the installation is complete. After which, you are to review the entire installation checking all the connections are tight, all the wiring adequately supported, and everything has followed the manufacturer’s instructions.

Before you turn anything on, check the battery charger is set for the battery type of your boat. Measure the battery’s voltage with a multimeter before the charging cycle as it provides a good reference point and will come in handy if any battery issues come up.

You can finally power up the battery charger. This is done by plugging in the shore-power cord, energizing the main breaker, and tripping the appropriate branch circuit breaker. Once powered up, you’re required to do a battery voltage level check to make sure it is significantly bigger than the available reference voltage.

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What About a Remote Display?

Most times, some battery chargers end up being installed in an out-of-the-way location, and you cannot easily monitor it, and it ends up being too far. Some of the new boat battery chargers come with a design that allows the remote display to cab this issue. It’s one of the great features to look for when selecting a charger.

This feature provides a lot of information, though even the most basic units give all that you need, ie. DC output voltage, AC input voltage, total charge time, battery temperatures, current charge cycle info, and more.

The installation of a remote display is a breeze with its plug and play functionality- four mounting screws for the display and length of cable with phone jack-style connections on each end.


A high-performing battery charger can go a long way in increasing your battery’s life, and that is why much attention is given to it. Once your high-performing boat battery charger is up and running, stay on board and observe the first few operation hours. These are the final touches for your brand-new charger. After that, you are good to go.

We hope that you have found this article beneficial and that we have answered the question; How Can I Choose And Install a High-Performing Boat Battery Charger?


Hi, I’m John who owns multiple different boats and i love all kinds of water activities. From boating to fishing, from scuba diving to windsurfing, from water tubing to snow tubing.

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