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How to Charge a Marine Battery: Ultimate Guide

how to charge a marine battery
How to Charge a Marine Battery


So, if you have a boat, proper information about How to charge a marine battery should be learned. Just you have to know the necessary information and tools for repairing or charging it in any situation because how to charge a marine battery is an easy and trouble-free process. But proper steps and requirements you need to know very well.

Otherwise, a silly mistake can make your battery unusable or dead. So, awareness is a must before charging your marine battery. Nowadays, most of the marine batteries available in the market use the latest absorbent mat technology (AGM). So, there is very little maintenance required.

AGM batteries are straightforward to charge and take less time than other batteries. On the other hand, it is a rapidly damageable type of battery. Any wrong maintenance causes quick damage to the battery. Marine batteries should not be overcharged. And long-time unused marine batteries are also damaged permanently.

Category of Marine Batteries

Before driving to the primary procedure at first get knowledge about the different kind of marine batteries.

Starting Battery

Another name of starting battery is cranking battery. It is made with inside plates close to each other. It has a large area surface for discharge.  It is a quick chargeable.

Deep Cycle Marine Battery

The deep cycle marine battery has thick charging plates. So, it will be charged very slowly and discharge energy slowly. This type of marine battery used in a small boat, trolling motor, and drives that use in navigation.

Dual Batteries

Most of the leisure time boats need cracking and deep cycle battery at a time. Dual batteries full the requirement at a time. But the negative thing is that this type of battery did not perform well as a deep cycle battery.

Construction Materials of Batteries

Following important point should be known that your battery made with what type of materials.

All the different types of marine batteries describe in the previous section perform based on a chemical response create the energy release. There are three different types of chemicals used for the construction of the various batteries.

The commonly used battery made with a wet cell. These are comparatively inexpensive than the other one. Proper preservation can make it long lasting.

 The disadvantage is that they require to be amassing straight and could not hold out making noisy vibrations. These are very irritating when you are in a boat. The charging system is also risky.

Comparatively, gel batteries are covered by a protective cover. So, they are safer than others. The inside chemical is vicious gel. That does not tend to be leaked.  But the gel batteries will not be lasting so far for their overcharging tendency.

 There is the latest type of battery called AGM batteries. These types of batteries are vibration and noise-free. They can charge quickly and long-lasting. Proper maintenance should be needed for these batteries.

How To Charge a Marine Battery Step by Step Guide

Battery charging is necessary for getting better service from your batteries. Some people thought that there is no need for charging a new battery. But it is wrong!

Fresh batteries should charge properly after buying it. The charge can increase the capacity of a battery. To avoid unexpected awkward situation regularly charge your marine battery after each ride. Generally, my suggestion is that always keep 60-80% charge in your cell.

It will keep your battery health in better condition. So, charging the battery regularly is must be done the activity. When you went for fishing or just riding on the boat, the battery should be charged enough.

Choose the Right Type of Charger

Various kinds of marine batteries need different chargers. Based on chemical materials chargers differ from each other. Point to be noted that cheap chargers should not be used for your marine batteries. Standard chargers can damage your battery. Cheap chargers do not indicate battery status. So, you cannot understand if the battery is under charge or overcharged. On the other hand, a good quality charger keeps your battery healthy and active.

There are two different types of marine chargers, one is portable, and another is non-portable. In general, everyone thinks that the portable one is best for them. But it’s not. There are some negative issues with portable chargers. They are cheap and easily stolen from your boat. But the non-portable or onboard charger gives you better service and lasting for a long time. It is easy to use because it adjusts with the boat. You just plug it and charging will begin.

Single Stage Charger should be used for lead-acid batteries. If you use AGM batteries, then use the smart charger. It charges your battery evenly and indicates the battery status.

Check the Battery Status

 Usually, marine batteries set in the very central position of the boat. So, dirt and other water substances cover the battery. Before starting the charging procedure, you should check the battery and clean the battery correctly. Otherwise, the charge would not do properly.

 At first, select a proper place for charging your battery and unboxed the battery to prepare it for charging. Then turn off the battery switch. Do not charge your battery in active mode. It causes a severe accident during plug in the charger point into your battery.

Check both terminals of your battery. If there is any rust, then remove them immediately. It can cause a hamper in the charging procedure. Not only charging time. You should clean your battery regularly. It will help to keep your battery healthy and durable.

Battery Should Connect to the Charger

After cleaning processes, you can start your charging processes.  The marine batteries connection terminal connects with the charger.

After connecting the charger and batteries, turn on the battery charger and let the battery to charge.

Before setting the charging, everyone should follow the instructions that are given in the battery or charger instruction. The instruction gives you the right direction to keep your battery charge correctly.

The central part will do the charger. It will be a little easier if you have a smart charger for your marine battery. You can check the battery charging status or charging amounts. The quick charger will automatically adjust the charging procedure.

Though you are using the smart charger for your marine batteries charging system, hence there is no risk of overcharging the battery. Overcharging cause damage to the battery especially if your battery is new. Do not use the old or cheap one for charging your battery.



Precautions should be taken.

Marine batteries include some hazardous elements that could cause accidents. For that reason, some precautions should be taken before charging your marine battery.

  • Before starting the charging process always follow the user manual.
  • The charging area should be well ventilated.
  • You should use safety clothes, gloves, and goggles during this procedure.
  • The charger should be plugged off during the connecting process. 
  • Before charging the battery box should be unboxed. 
  • Batteries should be clean up properly.
  • If the battery gets too hot, charging should be paused for some time.
  • Do not shake the leads during the charging process. Shaking might go because of firing.
  • Keep the battery always clean and rust free.

You can read

1. What is a marine battery?

2. Odyssey 34M 1500ST  Thunder Marine Dual Purpose Battery.

How to Charge a Marine Battery – Final Words

The charging procedure of marine batteries is simple and easy. But everyone should have the proper knowledge about the whole system. Types of batteries types of chargers should be adequately known. In the above discussion, I think you can get an idea about How to charge a marine battery properly. To avoid an unwanted situation, everyone should know the system. So, next time you go for boat riding or fishing then your journey will be safe and hazard-free. If the battery will fall, the described procedure will help you to charge your marine battery without any difficulties. I hope this article will help you to charge your battery.