Optima: What Voltage is Considered Bad for a Car Battery?

Optimal Performance

Did you try to start your car and all you heard was a clicking sound? That probably means your battery wasn’t charged enough to start your car, but does that mean it is bad? Not necessarily. Sometimes it just means the battery is discharged and needs to be fully-charged with a battery charger. The same is true when measuring battery voltage to determine if a battery has gone bad.

optima battery in car

Fully-charged, most car batteries will measure at least 12.6 volts (~13.0-13.2V for OPTIMA YELLOWTOPs), but low voltage doesn’t necessarily equal a bad battery. Modern cars are very demanding from an electrical perspective, even when they’re not being used. If these newer cars sit unused for an extended period of time, the battery voltage will probably drop well below that 12.6V threshold. While voltmeters can be picked up cheaply at just about any auto parts store and might give you some insight as to what’s going on with your battery, it is not a definitive measurement to determine battery health.

If you suspect your battery might have gone bad, measuring voltage is a good first step. If the battery is below 12.6 volts, you should attempt to charge it with a battery charger. However, you should know that some chargers will not recognize or charge any battery that has been discharged below a minimum voltage level, sometimes as high at 10.5 volts. OPTIMA Chargers can deliver current to batteries that have been discharged down to 1.25 volts.

Once you have attempted to fully-charge your battery, you should have it load-tested by a battery professional. Most auto parts stores offer this service and most will be happy to test it for free. A load test, not a voltage measurement, is the most-accurate way to determine the health of your car battery.


OPTIMA Batteries logo


OPTIMA Batteries







(888) 867-8462


5757 N. Green Bay Ave.

Milwaukee, WI 53209


With a 40-year history of technological innovation and engineering, OPTIMA products offer unstoppable power for extreme enthusiasts and others who require the ultimate power source. With OPTIMA under your hood, you can count on a longer-lasting battery life under starting and deep-cycle applications. For powering through the extremes of off-roading, racing, fishing, trucking and more, OPTIMA is the number-one brand of choice.