How to choose a marine battery

How to choose a marine battery

It’s not about rowing your boat with an oar anymore, as motorized boats are on the lead nowadays. To support the engine and plenty of other features like a fish finder, navigation light, and trolling motors - marine batteries have become an integral part of a modern boat.

But how to choose a boat battery for your vessel? That’s a tough question to answer if you don’t know the basics of marine batteries. Yes, batteries for boats come in different types, and not all types fit all the parts of a boat that have cell-adaptive spaces.

In this article, we will be looking at different marine batteries and how do you select the most suitable one for your boat.

What Is A Marine Battery 

Marine batteries, as you can tell from the name, are made especially for boats. These batteries come with heavier plates and rugged construction so that these cells can keep up with the constant vibration and pounding that are common for boats.

Types of Marine Batteries 

So there are different marine batteries you have to use on your boat. To make it easy for you to grasp, here are some quick discussions of these different battery types.

There are commonly three types of boat batteries.

  • Starting Battery
  • Deep-Cycle Battery
  • Dual-Purpose Battery

Starting Battery

The starting battery is often referred to as cranking batteries, as well. This is because the batteries turn over the engine of the boat. Now, a starting battery comes with a high energy burst of around 75 to 400 amps.

This high-energy burst lasts about 5 to 15 seconds only. But the battery can be quickly depleted and need to depend on the alternation of the engine to regain the charge it has lost. 

The plates in the lead-acid units are both positively and negatively charged, and the insulation separates both the plates.
Starting batteries need to rely mostly on a higher number of thin plates that help the batteries to push the high energy burst that kickstarts the engine of the boat.

Out of these three types of batteries, the starting one is the most fragile one, as well. This battery can hardly endure any hard impact and tend to break down easily. If you are using it for a long-discharging session, the battery will be degrading in a faster fashion.

Apart from starting the engine, the battery can be used for navigation panels, courtesy lights, and other general marine electronics. 

Deep-Cycle Battery 

The key application of a deep cycle battery is the trolling motor. The electric motor of the boat needs incessant delivery of energy that is handled by the deep cycle battery. These batteries can bring in a good amount of energy that can be withheld whenever it is needed.

Unlike the starting batteries, the deep-cycle cells are a bit different when in operation. These batteries don’t start with a bursting sound and remain mostly silent. As these are designed to support the engine for a long time at a stretch, these perform totally differently than the starting batteries. 

Compared to starting cells, these batteries are made from thicker plates with higher antimony content. These batteries tend to discharge their charge faster than the starting ones, usually at 45 to 75 percent of their capacity. 

The most common use of a deep-cycle battery is, as we said, the trolling motor. So before you get one, you should make sure that the one you choose can house at least double the energy you are planning to utilize before you set it for a recharge.

Dual Purpose Battery 

Usually, boat owners go for either a starting battery or a deep cycle one for the common purposes to serve. But there lies another type that should also be considered while you go for a marine battery. This third option is known as a dual-purpose battery.

The dual-purpose batteries come with thick plates and a greater level of antinomy. It is way better in performance compared to the starting one and comes with deep discharge capacity, as well.

As the energy storage capacity of this battery doesn’t come as equal to the deep-cycle ones, these are not considered as the best replacement for them. So it’s not that the dual purpose batteries are the equilibrium of both starting and deep-cycle batteries.

But these batteries surely come with a lot of potentials that can handle both the jobs of those two types of cells. That’s why using a dual-purpose battery may depend on the purpose of your use. If you need 

  • A battery for a single-battery fishing boat that handles both the engine starts and the non-engine power requirements.
  • To handle general electric needs of a boat

Then a dual-purpose battery may be a good suit for you.

To be specific, a dual-purpose battery is not the all-that-I-need type. It can carry on the duties of both starting and deep-cycle batteries, but it’s not expected from it. If you are looking for long-term use, then purchasing both these types of batteries will be a wise decision.

Factors to Consider Before Buying A Marine Battery For Your Boat 

So now that you have a grounded idea on different marine battery types, here’re some vital factors you need to consider before getting a battery for your boat.


The first thing you need to ensure is what exactly you are going to do with the battery. As we have already discussed, there are basically three types of marine batteries that you can use depending on your need.

Whether you need it for kickstarting your boat engine or simply run the electronic parts of the boat, you need to select from the three common types of cells. So this is the very first decision you need to make.

Chemical Technology

Apart from those regular batteries, you can also differentiate the cells by the chemical compositions they come up with. You can select from flooded batteries, gel batteries, and AGM batteries for your boat.

Flooded ones are made from a mixture of sulfuric acid and distilled water. And the AGM one is the same mixture with a fiberglass mat in it. And if you put the mixture in a fume tube, you get the gel battery.

As for longer support, you can always go for the lithium-ion batteries, as well. 


The more the output amps, the more powerful the battery. So make sure that the battery you are picking up is capable of a good amount of output amperage. It will make it more powerful and efficient.


Typically, once fully charged, a marine battery must be held at a lower voltage rate. This is to maintain the charge of the battery. A voltage set up between 13.2V to 13.4V is usually a good range to maintain. This is because the higher the voltage level, the quicker the charge will drop.


Set by the Battery Council International, the group of the batteries refers to the physical dimension of the battery housing. There are usually 8 types of groups to choose from. Depending on the length and width of the battery holder, you can select the appropriate group of the battery. 

Date Codes

It is important that you read the date codes for each battery before you use them. For example, the flooder battery date code comes with two letters and a number. The letters refer to the month it was produced and the areas it was manufactured. The numeric code refers to the year it was produced.

As for the AGM battery, the code comes in a DDMMYY format for an easier understanding. So make sure you check these date codes to ensure if the batteries are going to work well or not. 


Although weight is not going to be a determining factor when you have no choice to choose one that is a perfect fit for your purpose. Still, if you have the option, there’s nothing wrong with exploring the opportunities.

Make sure that the battery is lightweight and easy to carry. It will pave the way for you to handle the device pretty easily. Installation of the battery will be much easier and handier.

Vibration Resistance

The boat will cause ample vibration and trembling while you ride it. It will spear through the tides like a raging rhino that will cause the boat to have ups and downs in regular intervals. The batteries, in this case, may face a problem.

If not well-grounded and well-placed, the battery may come off its place and disconnect from its position.

Again, the inner construction of the battery may also get harmed if it is not resistant to vibration. So you need to make sure that the battery you are getting comes with vibration resistant features. 

Installation Position

Every battery has its own installation position. You can’t set a starting battery in a deep-cycle battery’s place, can you? So you need to make sure that you are installing the cell in the right position.

Again, make sure that the battery size is perfect for the place you are about to put it into. Is it going to suit it? You need to make sure you are answering the question correctly.

Fast Charging

You’ve got no time to recharge the battery when you are in a hurry. For a fishing boat, wasting a moment means a lot of fish is lost. So, recharging the battery shouldn’t take much of your time. That’s why choosing a battery that comes with a fast-charging capacity is a must.

It will make it easy for you to simply connect the charger and get the battery recharged in no time. 

Easy Maintenance

There are two things you need to keep in mind when it comes to maintaining the battery. The first thing is, the maintenance should be easy to carry on. You can’t afford to use complex tools to take care of the batteries all the time. So, the easier it is to maintain, the better.

Secondly, maintenance should be less costly. You don’t want to reach the bottom of your pocket for maintenance.


You need to check the warranty offer for one reason - to make sure the device is a powerful one. Usually, the longer the warranty period, the more powerful the battery is. So, try to stick to the batteries that come with a longer warranty period.


Last but not least, do keep your eyes on the price tag. Of course, you can find a lot of batteries that may cost a fortune, but it’s not worth it for your purpose, is it? So, be sure to keep the budget in check and make sure you manage the best one within your budget.

Final Words

We hope now you have the necessary know-how of how to choose a boat battery. Try to put tick marks on each of these factors that we have mentioned to make sure that you get your hands on the best marine battery for your boat.

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