Will An Alternator Charge A Bad Battery. A bad diode inside the alternator causes this. You can jump-start a car with a bad alternator but youll need to charge the battery for 3 or 4 minutes first.
This starts the engine running which puts the alternator into action. The fact is an alternator charge the battery in a very low voltage if the engine is idle. Any number less than that indicates its not capable to charge the level of battery completely.
This starts the engine running which puts the alternator into action.
But when you drive the car when the engine is running your car alternator can quickly charge the battery. FYI a bad alternator can actually damage a new battery but more on that later. In both cases it drains the long-term battery life. Leave the cables attached for several minutes and have the driver of the working vehicle press down on the accelerator while their vehicle is in park.
