Batman 11/13/2010There could be a dome light or trunk light in your car that is staying on. Or your battery may be shot. If you take it to a battery place they will typically test it for no charge and if it's bad..ouilla you're already at the battery place. If you have a voltmeter and a little know-how you can find out a few things from your driveway.
1. check the water(electrolyte) level in all 6 cells.
2. If you have or want to get a hydrometer (turkey baster lookin' thing) you can test the water(electrolyte)
3 With the voltmeter, if the car is turned off you should get around 12V across the terminals.
4 When the car is started the voltage should not drop below 9 while the starter is cranking.
5 Right after it starts, the voltage should be over 13 and should stay well over 12 while it is running.
6. If you want to test for a current draw (a light that's still on or a short): with the car turned off, disconnect one battery cable, configure the voltmeter for Amps and connect one probe from the meter to the battery cable and the other to the battery terminal. The reading should be less than 1/10 of an amp or .1.
benz guy 888 11/12/2011besides checking other lights are on... the battery if it is good..you should also check the alternator...if the is a problem with the alternator it wont charge the battery, it may be grounded...needs to be rewired or replaced...hope his could help you.