Automobile starters, boat accessories, golf carts and recreational vehicles commonly use 12-volt batteries. The desired specifications of a 12-volt battery depend on its intended use. Deep cycle 12-volt batteries, for example, provide continuous power for a long time.
An automobile relies on a 12-volt battery to start the engine and power auxiliary functions such as lights, fan blowers and the radio, but once the engine is running on gasoline, it can recharge the battery. Golf cart engines and headlights may run entirely from the power supply of one 12-volt battery. A golf cart can usually run for a few hours on the battery, but then the user needs to plug it into an electrical outlet to recharge the battery.
Boats and recreational vehicles often use 12-volt batteries for auxiliary electrical functions. For boats, these functions include fish finders and running lights. Some 12-volt batteries come in waterproof casing that is specifically designed for use with boats. Users can also purchase waterproof casing separately to protect a battery from water damage. Recreational vehicles use 12-volt batteries to power lights and appliances on camping trips where no electricity is available. Recreational vehicles often have two or more 12-volt batteries to meet the power demands of the entire vehicle.