Deep Cycle Marine Batteries

A battery is a device that stores chemical energy to generate electricity. Batteries can be classified into two types; one is by their application and the other by their construction. They are widely used in automobiles, marine and deep-cycle.

Deep cycle marine batteries are basically used in marine applications. They are rechargeable and sealed batteries. They are used in houseboats, yachts, watercrafts and other kinds of boats. They are also used in non-marine applications like in golf carts. These batteries are designed in such a way that they can be deeply discharged. They comprise of heavy-duty lead plates and not sponge. They have a long life as the high-density oxides in them reduce their wear. Deep cycle marine batteries are durable, efficient and economical as they contain deep cycle lead acid, which helps them to discharge slowly. Due to these characteristics these batteries last more than conventional starter batteries. They are strong batteries and there is no leakage if they are tilted, inverted, or in some case even broken. They are available in three types: lead acid, gel cells, and Absorbed Glass Matt (AGM).

1) Lead acid batteries: These batteries are made up of lead plates and lead oxide. It uses simple reactions to supply energy. The positive plate is made of lead dioxide (PbO2) while the negative plate is a spongy metallic lead (Pb). Both the positive and the negative plates are converted to lead sulfate (PbSo4). The electrolyte used in these batteries is a mixture of diluted sulfuric acid, which produces the sulfate ions that are required for the discharge reactions. The electrolyte solutions of lead acid batteries comprise of 35% sulfuric acid and 65% water. They are hardy and can withstand considerable rough usage and severe conditions. Lead acid batteries are often used as sources of backup power in the event of the electrical power or the primary battery failing.

2) Gel cells: They are also known as “gelled batteries”. The acid in these cells are gelled, or turned into a gooey mass, by adding silica gel to it. The best feature of these batteries is that the acid does not spill even if the battery is broken. Gelled batteries need to be charged slowly and at low voltage so that the gas does not damage the cells. If these batteries are charged too fast or are overcharged, it may result in permanent damage. Overcharging of gel cells causes voids to develop in the gel that cannot be rectified, and reduces the capacity of the battery. If gelled batteries are used in hot climates for 2 to 4 years, there is heavy loss of water, which damages the battery prematurely. As gelled batteries require high maintenance, the newer AGM batteries are preferred.

3) Absorbed Glass Mat Batteries (AGM): These are sealed batteries in which absorbed glass mat is used. Absorbed glass mat is actually a fine boron-silicate glass mat. The AGM is placed between the plates of the batteries. Rather than being completely soaked, the mat is saturated up to 95%, which is why they are also referred to as “starved batteries”. This mat prevents leakage of the acid even if the battery is broken. AGM batteries are relatively new in the market. They can withstand more rough usage than gelled batteries. They are more resistant to shock and vibrations. They even function at extremely low temperatures, as they have no liquid that freezes and expands. AGM batteries cost the same as gelled batteries, with more features, and they are non-hazardous too, so shipping them is much cheaper.