Details about marine battery charger and how to select

In this article, we’ll be showing you the right steps to consider and the right questions to ask when picking the best marine battery charger for your boat.

How does an onboard marine charger work

Just like any other charger, a marine battery charger is used in charging a marine boat battery, supplying it with the current needed to charge up the boat battery to an optimal level.

The charger for a boat battery is usually mounted on the boat itself and only needs to be connected to a power outlet or grid to be able to charge the onboard boat battery.

The Marine battery charger converts raw AC electricity to DC which is the current required by most devices and appliances on the boat.

How long do marine battery chargers last

The life span and duration at which a marine battery charger will last depends a lot on the maintenance practices applied with the charger. This involves how the charger was used and under what conditions.

One of the major factors that determine how long a marine battery charger will last is the kind of battery it’s used with.

For instance, using a lithium battery alongside a lithium boat battery charger will prolong the charger’s shelf life mainly because lithium batteries are safer to use compared to other battery types.

Also, leaving your marine battery charger plugged in indefinitely can affect the charger’s efficiency and how long it lasts. This in turn depends on the type of charger being used.

If you prefer to leave your charger plugged in indefinitely, it is recommended you use a smart trickle charger instead.

A trickle marine battery charger doesn’t work the same as a regular charger as it works by supplying small amounts of electricity to the battery and safely charging it over a longer period of time.

Do I need a special charger for a marine battery

Whatever marine battery charger you use must be compatible with the onboard battery. The right battery should be compatible with the voltage and chemistry material of the battery in question to prevent a mixed match which could lead to your battery overloading, like lithium batteries, you must use a lithium charger.

Also, the ideal marine battery charger should be water-proof as it would be used close to water, and the chances of getting wet are very high. The charger should also be able to be mounted in a fixed position to avoid movements that may damage the charger.

What features do you need in a boat battery charger

The right features that a marine boat battery should have depend on the needs and power requirements of the boat battery in question, some of which are listed below;

Versatile Charger: A good marine battery charger should be able to charge any type of marine Battery using either solar energy or a power grid.
Water Resistant: Obviously a marine battery charger would be used on a boat that is always near water so there is always a possibility of the charger getting wet. So you should always look out for a battery charger that is waterproof or resistant for durability.

High Charge Rate: Most marine battery chargers are rated at a particular amperage and should only charge within that amp range. But practically, most chargers lose amperage as the temperature rises when the charger is in use.

For instance, a 50-amp charger for boat battery charges at 50 amps initially but after about 30 minutes of charge time, the amperage drops as the charger increases in temperature.

You should look out for a charger that maintains its initial amperage in constant current stage for as long as possible regardless of the increase in temperature.

Safety: A good quality marine battery charger should have certain safety features built-in the charger’s system. This includes features like temperature control to regulate the heat resulting from charging as well as current control to regulate current flow.

A good boat battery trickle charger would be ideal to maintain current flow at a safe level.

What size battery charger do i need

The ideal size of a charger for charging boat battery depends mostly on the battery it is meant to be charging.

It involves the voltage and amperage rating of the battery on the boat because both battery and charger need to be compatible for the charge to work properly without overloading the battery.

What voltage is a marine battery charger

Ideally, a 12v lithium-ion battery will be compatible with a 12v marine battery charger of the same size.

In considering the voltage of a marine battery charger, we first need to take into account the voltage requirements of the boat battery it is meant to be charging.

A charging boat battery commonly supplies between 12V or 24V but could vary depending on the battery setup. This voltage could also go up as high as 36V or 38V depending on the battery so the battery should be set up accordingly.

How many amp battery charger do i need for marine battery

Practically, the higher the amperage of the marine battery charger the faster it would supply current and the faster the battery will charge.

This is an indication of the charge rate of the boat battery and currently, lithium-ion batteries have a high charge rate of 0.2~0.5C while lead-acid batteries have a lower charge rate of 0.1C.

For instance, a 100AH charging at a 0.5C rate (50Ah × 0.5C) would charge at a maximum of 25A.

The same could be done for the lead-acid battery of 100Ah (100Ah × 0.1C) at a maximum of 10A. In essence, the lithium battery would take just 2 hours to charge while the lead-acid battery would take up to 10 hours to fully charge.

What type of marine battery charger do you need for a marine battery

There are currently different types of boat batteries available all of which perform differently. These batteries include house batteries, boat batteries, or trolling motor battery.

The different battery types which include either lithium-ion battery, lead-acid battery, or others would determine the kind of marine battery charger to be used.

Overall, lead-acid batteries are more sensitive and run the risk of easily overheating while a lithium-ion marine battery charges faster, is more versatile and adaptive, and can handle a wider range of boat charger types.

Which type of marine batteries and chargers are the best

As we’ve established, lithium-ion marine batteries have several benefits over lead-acid some of which include the fact that lithium batteries can be discharged and charged more than once each day while lead-acid batteries are only limited to one charge cycle each day.

Lithium batteries also take about 4 – 6 hours to fully charge while lead-acid takes up to 10 hours to complete a charge.

Can you overcharge a marine battery

Depending on the kind of marine battery charging method or charger you use, it is indeed possible to overcharge your marine battery. One major way to avoid this is by using a trickle marine battery charger.

A trickle charger supplies small amounts of currents to the battery and effectively charges the battery for a much longer period. Even if this will not cause great harm to the battery, we still have to pay attention to the health of the battery and unplug the charger in time.

Another added edge is that it can be used with both lithium-ion batteries as well as lead-acid batteries. Always be sure to check the charger for safety precautions and the limit to which the charger can be connected.

How often should i charge my boat battery

This ultimately depends on how frequently you use your boat and how much power you drain from your boat battery. If you use your boat only once a week, then 1 complete charge should be enough to power the battery.

But regardless of how frequently you use your boat, the boat battery discharges even when not in use so it would most likely need to be charged before the next trip.

This is why a lithium-ion battery is recommended because it has a very low rate of self-discharge（3% per month） compared to other battery types. And using a trickle marine battery charger will go a long way in making sure the battery stays charged at all times.

How do i know if my marine battery charger is working

A marine battery charger usually comes with indicators designed on the body of the charger. These indicators are commonly red lights, green lights, and black lights.

The red lights indicate that the charger is working, while the green light usually indicates the percentage of charge left to fill the battery. The black color usually tells that the charger isn’t conducting the needed current.

This differs with each brand of marine battery charger and you can always tell by connecting a multimeter or voltmeter to the charger.

A positive number on the multimeter indicates that the charger is working while a negative number indicates otherwise.

Can I use a trickle charger on a marine battery

As a boat charger, Trickle chargers are some of the most used marine battery chargers for several reasons. While most regular boat charges offer fast charging with a steady supply of high levels of energy, trickle chargers do the opposite.

Trickle chargers allow a small amount of electricity to pass to the battery which supplies a small but steady current flow for safer charging.

What makes a battery charger not work

There are a few reasons your marine battery charger might not be working some of which include poor input or low current input from the power grid or solar inverter.

The temperature could also prevent your charger from working as overheating usually damages a marine battery charger. Another reason could simply be a faulty charger that needs to be replaced.

How can you tell if a marine battery charger needs to be changed

You can do this by checking the indicators on the Marine battery charger or a voltmeter connected to the charger. A negative reading generally indicates that the battery isn’t giving off the needed amount of power and hence, needs to be changed.