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The Complete Marine Batteries Guide For Boat Owners

Like all other commercial vehicles, boats too require batteries for running. These are meant to take care of two basic tasks, starting the engine and running the electrical equipment such as lights, accessories, and electronics on the boat. These are like the lifeline for the boats as they perform such crucial tasks. Hence, it is advisable to choose wisely when you buy a marine battery online or in-store. A complete overview regarding the types and chemistry of these batteries would help to make the right choice.

Types Based On Battery Application

In the first classification, they are divided into two categories based on their application:

Cranking/Starting Batteries: As the name suggests, these are meant to start the boat engine. These are designed to deliver a massive jolt of electrical power for a very short time span and then be recharged quickly. It is to be noted that the battery needs to be recharged the same way it is discharged; therefore, cranking battery is meant to be recharged at a rapid pace.

Deep-cycle Batteries: The function of these batteries is to power up the electrical devices and accessories on board, such as the radios, trolling motors, fish finders. These are built to supply limited power over a longer time span. As a rule, these take a longer time to recharge because these get discharged slowly.

In addition to these two basic types, online battery suppliers also recommend the dual-purpose type for some marine vessels. These are designed to perform the functions of both the starting and deep-cycle batteries and are suitable for small powerboats and sailboats having two identical ones which are used interchangeably for the purpose of starting and house electrical loads.

Types Based On Battery Chemistry

Another classification of is done on the basis of chemistry:

Wet-Cell Batteries: Also known as “flooded-cell” batteries, these contain a liquid mix of sulfuric acid and distilled water, termed as “battery acid”. These make a cost-effective option as they last long, delivering up to 1,000 discharge/recharge cycles. They are lightweight in comparison to the AGM type and also are less susceptible to damage by overcharging. However, they have vented, interior accessible designs. There is need to inspect them regularly and ensure that the cells are topped off with distilled water. Also, there is a possibility of the acid spilling and the rate of self-discharge is high for them.

AGM Marine Batteries: AGM (absorbent glass matting) batteries have a dense filling of absorbent glass matting which is packed between the battery’s plates. The acid electrolyte in the battery enables the replenishment of its water content by allowing the oxygen to recombine with hydrogen gas to form water. This eliminates the need to refill it, thus making it a low-maintenance option. AGM is shock resistant, can be installed at any angle, and present a low self-discharge rate. The drawbacks include greater weight and higher cost. Also, it is not possible to replace the water in case of accidental overcharging.

Gel Batteries: Gel batteries are infused with a liquid electrolyte which is turned into the gel form with silicates before sealing the battery. This one too does not require the addition of water.  The battery does not need maintenance, is shock resistant, low-temperature tolerant, and has a long cycle life. The most significant benefit is that this battery does not get over-charged, while the internal self-discharge rate is also minimal. The price is the biggest downside for the gel type. Also, they have to be charged with special chargers specifically meant for the gel type.

The choice of marine batteries is to be based on a proper understanding of the various options and considering the one that would suit your requirements to the best. The 4d marine battery makes a popular option for most of the buyers. However, factors like starting functions, size, longevity expectations, etc are to be borne in mind to make an apt choice.