Can You Test A Battery While The Car Is Running. Enter your cars year make. Next you should only test a battery after its been sitting unused for at least an hour.
The depleted battery indicates that some part of the electrical system is not functioning properly. Once the vehicle is up and running the alternator can take the ability to run your cars electrical system and maintain battery levels. In theory if your alternator is providing adequate power to the car while charging the battery then once the car is started disconnecting the battery should not cause the engine to stop running.
The alternators regulator can only react so fast to a massive step change in load such as when you unhook the battery while the car is running.
Test the battery voltage. If you dont have a multimeter to tell you the voltage of. Should anything happen to your alternator if it stops providing a charge to the battery your car battery can die while the engine is still running. Not to mention that this is a really really bad way of checking for a bad alternator.
