How Long to Charge a Dead Battery at Idle Speed?
1 Answers
Charging time for a dead battery at idle speed: If the engine speed is 1500 rpm, charging for 20 minutes can provide enough power for the starter to crank the engine once; charging for 30 minutes at 1500 rpm can ensure one successful start the next day; if charging at 1500 rpm for over 60 minutes, the battery can be almost fully charged. It is recommended to charge the battery while driving rather than at idle speed, for the following reasons: 1. Carbon buildup risk: Prolonged idling can cause carbon deposits to form in the engine combustion chamber; 2. Inefficient charging: The alternator produces weak electrical output at low speeds, and only reaches its designed standard current output during normal driving conditions.