How Do You Test Car Battery Capacity?
Car battery capacity is measured in cold cranking amps. This is defined as the amount of current, in Amperage, that your car’s battery is capable of delivering under specific conditions. Car batteries, depending on size and need, are able to deliver anywhere from around 400 cold cranking amps to well over 1,000 cold cranking amps. Your car battery’s capacity can be tested by hooking it up to a load tester. A load tester is a carbon pile of known resistance value. Once connected, current is allowed to flow through the known resistance load and the current and voltage are measured.
For more info, see Choosing the Right Car Battery Tester