Choosing a marine battery require that you match the marine battery to the needs of the boat that will use the marine battery. A marine battery that isnt the correct type for the boat, however, may fail to provide enough power to the boat system. The type of marine battery that is required, therefore, is based off the use of that marine battery; batteries for starting engine are of a different type than batteries for powering electronic devices on a boat.
There are three main types of marine batteries. Starting marine batteries are design to provide a burst of power to start an engine and then to sit idle. Deep cycle batteries, in contrast, are designed to continuously provide power to devices on a boat (devices like trolling motor or lights), and deep cycle batteries has different internal plates than starting batteries.
How to Choose the Right Marine Battery
Finally, there are dual purpose batteries, which are designed to provide the same benefits of both starting and deep cycle batteries. Starting batteries should not be used for deep cycling battery task, however, because they isnt constructed for deep cycling. Beyond the three main types, there are also different size for marine batteries.
The size of a marine battery is represented by it’s BCI (Battery Council International) group number. The BCI group number indicates the size of the marine battery as well as its capacity. For instance, a Group 24 battery is a small and lightly battery that is often used in small compartments on a boat.
A Group 27 battery has a longer length than a Group 24 battery, and therefore provide more capacity. Even larger batteries exist, such as 4D or 8D batteries, which are heavy and large in size but contain more amp-hour reserve for deep cycling applications. Because these deep cycle batteries are longer than starting batteries, it is important to make certain that the compartment on a boat will have enough length to accommodate for the deep cycle battery.
The technical specifications of the battery will also help to determine how the battery will perform. Factors like the cold cranking amp for starting an engine, the reserve capacity for powering devices when the engine is off, the amp-hour rating for how much energy the battery can store, and the depth of discharge limit for how much that battery can be drained before it is damaged will all need to be reviewed. It is important to understand the power draw of the boat to ensure that the marine battery has the apropriate amp-hour specification.
The chemistry of the battery will impact both the functioning of the battery and its cost. For example, flooded lead-acid batteries are inexpensive but require regular inspection of the water level inside the battery. Absorbed glass mat batteries are more expensive but have more flexibility in how they are mounted on a boat, and they can better tolerate the vibration of the boat.
Gel batteries are also constructed for high vibrations but require a specific charger to function properly. Finally, lithium iron phosphate batteries are the most expensive but are among the lightest batteries and have the longest life cycles. Beyond determining the battery specifications, the type of boat that will use the marine battery will also determine the type of battery that is required.
For instance, kayaks dont require heavy marine batteries because they use relatively few electrical device. Bass boats, however, require both starting batteries and deep cycle batteries to power trolling motors. Boats like pontoon boats and cabin cruisers require more power, though, and often require larger marine batteries or multiple batteries connected together to provide that power.
Sailboats and houseboats require among the largest batteries for those applications because there are many system that need to run throughout the night. If you are to connect multiple marine batteries together on a boat, there are specific rule regarding that process. For instance, you can connect batteries in series so as to increase the voltage of the battery bank.
Every battery connected in series, however, should be the same age as each other and each battery should be in the same condition. If one battery in a series is older than the others, or has been deeply cycled more often than others in the series, it will lose the total capacity of the battery bank made up of those battery. Battery life can be extended by following some basic maintenance guidelines for the battery.
For instance, you should keep the battery terminal clean so as to not lose voltage at the batteries. If the boat is to be stored for long periods of time, a smart charger should be used for the batteries to prevent the formation of lead sulfate on the plates of flooded lead-acid batteries. Additionally, you should inspect flooded lead-acid batteries every few weeks to ensure that the water levels are maintained.
Finally, the battery should be selected according to the size of the compartment on the boat where the battery will be stored, as well as in response to the power requirement of the boat itself.
