Question

Why can car batteries run on low voltage?

Answer 1

Charging problems can be caused by electrical faults in the alternator or voltageregulator, poor wiring connections at the battery or alternator, or a slipping or broken drive belt. ... Using a voltmeter to check for voltage drops across connections can reveal bad connections that may reduce the charging voltage.

Answer 2

Answer:

A car battery can run down for any of several reasons: You accidentally left the lights on or some other accessory that pulls power from the battery even when the ignition key is off. The battery is not being recharged while the vehicle is being driven (you have a charging problem)