Marine Batteries

There are three basic types of boat batteries as far as application is concerned. The first, and most predominant, is the starter battery. As their name implies, they’re used for starting your boat’s motor. These are designed to provide a lot of energy for a short burst.

Another kind of marine battery is the deep cycle battery. These are intended to provide a smaller amount of power, over a longer period. Unlike starter batteries which provide a large burst of power over a short period, these provide steady and consistent power over a longer period. Deep cycles are used to run trolling motors, radios, and other auxiliary systems.

The last type of battery commonly used in marine applications is the dual-purpose battery. This battery can serve double duty but isn’t perfect for either. Some dual-purpose batteries aren’t strong enough to start larger motors.

Dual-purpose batteries also run the risk of leaving you stranded if you aren’t attentive to how long you have used them. If you drain the battery while listening to music at the sand bar, it may not have enough power to start your motor. 

Battery power has made leaps and bounds across all applications from phones to electric cars. Marine batteries are not an exception. In the past 20 years boat batteries have improved across the board. Old technology has been improved and new technology has been introduced and adopted with great success.

The chemistry and composition have a lot to do with their performance, and each kind has drawbacks. There are four different types of batteries when it comes to chemical composition.

The flooded battery, or wet cell, is the oldest and most traditionally used type of battery in both the automotive and marine world. The flooded battery use lead plates, a sulfuric acid electrolyte, and plate separators to store and discharge energy. The wet cell has a few advantages and disadvantages. They are not sensitive to overcharging, and they’re cheap. They have quite a few drawbacks, such as weight, gaseous discharge, and maintenance.

Wet cells are heavy and bulky, a combination that typically doesn’t bode well for boating. They require maintenance to keep their fluid levels adequate since their fluid can evaporate during both normal usage and charging. When charging, wet cells emit hydrogen gas and can also leak battery acid from the discharge vent. One final drawback is that they can be sensitive to vibrations and movement, something that is very common in boating.

This isn’t to talk anyone out of a flooded battery; they have provided millions of fun days on the water, and are still in use across the world. The flooded battery can provide plenty of fun days on the water at a great price, but it is important to know its limitations and drawbacks.

The absorbed glass mat battery, commonly called AGM, has a fiberglass mat in between each lead plate. These fiberglass mats hold the electrolyte solution in between each plate through capillary action. The AGM battery has its advantages and disadvantages as well. It’s maintenance-free and won’t leak or spill. It’s a sealed battery, so there are no worries about maintenance, or leaking battery acid.

It’s also able to withstand more vibrations than the flooded battery. It does have two big drawbacks. It’s very prone to damage if it’s inadvertently overcharged, and it’s much heavier than the traditional wet cell battery.

The gel cell battery is made by using a gel cell to suspend the battery plates. The thick paste allows electrons to flow between the plates when in use. It’s similar in characteristics to the AGM battery. The gel cell battery is maintenance-free, leak-proof, and spill-proof. It’s also similar to the AGM battery in its susceptibility to damage if it is overcharged.

Another drawback is its higher cost in comparison to the other types. It is stronger in its ability to handle vibrations than a flooded battery but does not have the same power capacity as a similarly sized AGM battery.

Lithium-ion batteries also have some incredible options. The Abyss 36-volt battery has a Bluetooth connectivity option to track the charge of your battery on your phone. Not only are lithium-ion batteries maintenance-free but they can also be discharged almost completely without causing any damage to the battery. Lithium-ion has a massive upfront cost, but with lifetimes of over eight years, and double the run time, the upfront investment makes sense.

The small size of lithium batteries has led to some interesting innovations in their use with electric reels as well. Abyss Battery has designed them specifically made to power electric reels for use in deep drop, teaser, and kite reels.

Now that you have picked your battery, how are you going to charge it? On certain boats, the battery can be removed and brought indoors to be charged. In a lot of the boats, they are stored in a way that makes them difficult to remove, and they aren’t exactly light.

A quick and convenient way to charge your battery is through an onboard battery charger, also known as a battery tender. These can come in different shapes and sizes and offer the ability to charge from a shore power plug, or even from the power produced by your motor.

Some lithium-ion battery manufacturers recommend a battery tender designed specifically for lithium-ion batteries, while others say there is no need to use a specialty charger. Abyss makes onboard chargers designed specifically for lithium-ion batteries in marine use, providing safe and efficient chargers. 

Battery maintenance is necessary on all batteries to varying degrees. Wet cell batteries have an electrolyte solution that needs to be refilled on occasion. To check the levels in your battery, pry off the plastic covers over the cell ports. If the plates are exposed or coming close to being exposed, add distilled water. Be sure to wear gloves and safety glasses when checking your battery, as prying off the caps can sometimes cause acid to splash loose.

The other three types described above don’t require nearly as much maintenance. It’s a good idea to check your batteries before use to make sure there are no signs of corrosion on the battery terminals. Dielectric grease can be used on your terminals to inhibit any potential corrosion. Make sure your terminals all have clean contacts and are tightened down. Be sure to keep an eye on whatever battery tie-down system you have in place; they can deteriorate and leave your battery unrestrained.  

Battery technology continues to improve across a variety of applications. As it improves and you choose to replace your battery, be sure to dispose of the old one properly. Many automotive parts stores will provide store credit in return for used batteries. Most battery components are recyclable, as a typical lead acid battery contains between 60 and 80 percent recycled lead and plastic.

The correct battery and proper maintenance can provide carefree boating for many years. Remember to dispose of your old batteries properly to ensure clean water boating for generations to come. 

For the last 40+ years, we’ve perfected the art of upgrading boats and helping boaters better enjoy their time on the water. If you have a question about a product or project give us a call! Our team of experts is here to help!