How To: Test Your Cars Battery

[@NafanyaZX]

Testing voltage merely shows you the charge. It is not an indicator for battery health. For example, even if you see good voltage, understand it drops under load. Whether or not the voltage drops too much under load, is the actual test. That's why a battery tester is a separate tool from a multimeter.

[@LogosFarm]

@@NafanyaZX Is a neutral rev enough to simulate “under load”?

[@NafanyaZX]

@@LogosFarm In this case "under load" means something draining the charge. Revving an engine does not drain the battery, it charges the battery. So no. Cranking the engine is what the battery testers simulate. So make sure the car can't start (pull fuel pump fuse for example). Then watch the battery voltage, while comeone is cranking. Or set things up, so you can see the meter from inside the vehicle. What am I even saying? If your battery can crank the engine for 10 seconds, it's fine. No need to measure it, if you can see it doing it's job. Battery testers just save you the trouble of disconnecting things and then having to erase the error codes afterwards.