battery booster

A jump start, also called a boost, is a procedure of starting a motor vehicle (most commonly cars or trucks) that has a discharged battery. A temporary connection is made to the battery of another vehicle, or to some other external power source. The external supply of electricity recharges the disabled vehicle's battery and provides some of the power needed to crank the engine. Once the vehicle has been started, its normal charging system will recharge, so the auxiliary source can be removed. If the vehicle charging system is functional, leaving the engine running will restore the charge of the battery.
Motorists may carry jumper cables and other equipment in case of accidental discharge of the vehicle battery (for example, by headlights, interior lights or ignition switch left on while the engine is not running). Safe procedures for connecting and disconnecting cables are given in the vehicle manual.

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