Hi.
Once upon a time you put a heavy load across the battery, most garages had them it has a voltmeter to monitor the voltage during the test. One thing they would show was a low cell as it would gas, during the test if ithe voltage drops very rapidly to below 11 volts bin the battery.
If the battery is good it should not drop below 12.4v in the car after 12 hours after being fully charged. In fact I'd be looking for 12.6v.
Even the best battery will have a hard time with stop start so I don't use it on my car.
Once upon a time you put a heavy load across the battery, most garages had them it has a voltmeter to monitor the voltage during the test. One thing they would show was a low cell as it would gas, during the test if ithe voltage drops very rapidly to below 11 volts bin the battery.
If the battery is good it should not drop below 12.4v in the car after 12 hours after being fully charged. In fact I'd be looking for 12.6v.
Even the best battery will have a hard time with stop start so I don't use it on my car.