Many motor applications utilize a 12 or 24 volt power source. It is important for the application’s long term success that the battery and motor are sized correctly. Lead-acid batteries are popular for many of these applications, since they are usually the lowest-cost option and are widely available.

The energy stored in a battery, called battery capacity, can be stated in ampere-hours (Ahr). An ampere is a measurement of electrical current, and the hour indicates over what time period the battery can supply this current. Specified capacity is usually given based on the battery discharging uniformly over a 20 hour period. If you’re using the battery in an application that requires a much higher current, then you can expect much less than the rated hours.

A 100 Ah battery, for example, can supply 5 amps for 20 hours. If you need to draw more current, because a bigger device is connected, it will last for a shorter period of time than rated. An example would be that drawing 20 amps would drain the charge in much less than 5 hours.  If you are drawing lower amperage than rated, the battery can last longer than its stated capacity.

The two main types of batteries are “Starting” (cranking), and “Deep Cycle” (marine/golf cart). The starting battery is built to deliver a quick burst of energy, such as starting vehicle engines. The deep cycle battery has less immediate energy available, but can provide greater long-term energy. Starting batteries should not be used for deep cycle type applications. Your battery supplier can help you determine the best battery type for your application.