The subject of batteries could take up many pages. However, we will keep this to a minimal. A battery in short, is an electrical storage device. In a deep cycle battery, the design allows for electrical energy to be stored, released and recharged many times. This process is known as a cycle. Deep cycle batteries are commonly used in solar battery banks for off-grid systems,  EVs such as golf carts, forklifts, electric cars, scooters and generally any device that runs off stored energy. Your phone or laptop for example has deep cycle lithium batteries but for the purpose of this calculator app we will focus on wet, lead batteries. (although the philosophy is the same)

Deep Cycle batteries come in many shapes and sizes.  In the wet lead world, generally the larger and thicker the lead plates in the battery, the larger, heavier and taller the battery. This allows for the storage of more useable energy.


When using Deep Cycle batteries it’s a good to have an idea of how long your battery or series of batteries (bank) will last before there is not enough useful energy left. It’s great to have battery monitors but monitors can fail and also give erroneous readings if not installed properly. This is why it’s always good to know how long your battery can release energy when a load is applied to. In short, this is part of the basic math your battery monitor uses to display wether or not you need a charge. By entering certain parameters you can refer to the calculator to find out the estimated “life” of the battery before it’s “dead”. i.e. not producing enough voltage to run your equipment or vehicle. Most manufactures recommend not to drain the battery more than 50% of it’s rated capacity.

Remember running and electric motor on low voltage can spike the amps and overheat the motors.