I bought a multimeter to test my old or also the new car battery. Since I am layman I ask therefore, which value is important for the start of the car. Is the volt number the important number for testing how good the battery is still or when to recharge, or which value I have to read. In the measurement A (direct current) I get no value and if I fly around on measurement up to 10 A the sparks. Would be great if one of me this for unknown I have measured V DC voltage once, with the new battery is 12.93 and with running engine 14,53 With the old battery, which now stands a few days in the basement, the indicator jumps like wildly high and down to then eventually stabilize at 10.9. Thank you for the info!!!