Marine Batteries Explained

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15th Jun, 2020

A marine battery is generally used in a dual-purpose function. It is used to start the motor but can also used to supply power to the ancillary loads. As a result, it is imperative that the right choice be made to suit the application. The functionality of the battery particularly in the marine environment is often taken for granted. One should choose a battery that suits the load application but also has cranking capability.

Because a normal car battery is generally much cheaper than a marine battery, it can be very tempting to use this type of battery rather than a marine battery. We strongly advise against this practice as the long-term cost of ownership will be disappointing.

A marine battery is better suited for your watercraft.  They have been designed with specific needs in mind. Marine batteries have several advantageous features: they have cyclic capabilities for excess electronic demands, they have cranking capabilities, they are able to re-charge three and half times quicker:– in short they are stronger in all aspects and are designed to meet your outboard or inboard motor’s needs. With the correct maintenance and care, your marine battery should last you for several years.

When selecting your marine battery, it is imperative to match the battery to the application and the demands.  Choosing a battery that has too little storage capacity for your boat requirements could result in the need for more frequent, recharging. Your charging equipment should also provide sufficient power for your marine battery to restore it to full capacity. When a battery is consistently undercharged, this can considerably shorten its lifespan and/ or result in premature failure.

Marine batteries may be categorized by technology .

Lead Acid – Discover Mixtech

Lead Acid – EV DRY CELL

Lead Acid – AGM (absorbed glass mat)

Lead Acid – GEL

Lithium Ion.

·         Marine battery’s storage capacity is measured in ampere-hours (Ah).

·         The ability to start the engine or motor is measured in MCA – marine cranking hours

·         The RC - (reserve capacity) is the current in amps ( 25 amps) that the battery can supply with no charge from the alternator down to a voltage of 9.5 volts.

·         The usability of the battery is measured in what is termed the “CYCLE LIFE”

The higher the number of cycles permitted the longer the expected life of the battery  

DISCOVER - Mixtech Technlogy – a patented process which allows 360 degree mixing of the electrolyte inside the battery, enabling 100% interaction between acid and active material. This doubles the cycle life capability and enhances quicker re-charging

DISCOVER – EV DRY CELL - Absorbed Glass Mat (AGM) batteries consist of glass mat separators that are saturated with an acid electrolyte that is located between the negative and positive plates of the battery. When an AGM battery is charging, the oxygen that has been produced on the positive plate will move through to the negative plate with the help of pressure valves. The oxygen will then combine with hydrogen to form water.

In terms of vibration and shock prevention and absorption, an AGM battery is much better than other kinds of marine batteries. They also feature a lower internal resistance, meaning they produce a larger charge acceptance and starting power, leading to faster recharging than other deep cycle batteries.

An AGM battery is able to receive the highest charging current (i.e. up to a maximum of 40% of the battery’s Ah capacity).  Gel batteries, for instance, can only accept a maximum of 30%, and flooded batteries 25%.

In addition, with the longevity and very low self-discharge rate, the AGM battery is an excellent performer and makes exceptional dual-purpose batteries as they have a great deep-cycle ability.

There is a large choice of sizes in this range making it ideal for most applications.