I have a 2005 chevrolet cavalier and something keeps killing the battery; i had the battery and alternator checked; they are both good. what could be kiling my battery

You have a bad alternator. Get the alternator checked, the alternators in 98 cavalier require at least 13 to even start the car off of battery power. The alternator is what charges your car's battery while you are driving. if you have bad alt then your jumping the car is pointless cause it won't harge your battery at all it just kick starts the engine with power from the other vechile. If the alternator is showing at the very least more than 15 when its tested time for a new one. They should run about $90-110, it's an easy do it yourself installation to. Good Luck!!!

turn on heater to warm up player it works for me I have a 2001 it will only play when it is warm

Alternator may be bad, causing battery to lose voltage. I think you should have the starting/charging system checked, and replace the battery and alternator as required by the testing. I wouldn't drive it until this problem is fixed, as the car can shut down when the voltage gets too low, working off of the battery. Check whether the charge light is lit when the car is running. If it is, there is a self detected problem with the alternator. If not, there could still be a voltage charge problem, that hasn't been self detected, perhaps a diode is bad or voltage regulator is faulty, causing the alternator to barely put out enough power to keep the car running.

I would check cables and ground

REPLACE BATTERY CABLES SEE WHAT HAPPENS.YOUR BATTERY CABLES IS OLD HAVE A LOTS OF RESISTANCE IN THEM.MAKE SURE YOUR GETTING THE RIGHT AMP ALTERNATOR.BECAUSE A LOWER AMP ALTERNATOR WILL OVER WORK TRYING TO KEEP BATTERY CHARGE THAT WILL SHORTING ITS LIFE.CALL CHEVROLET DEALERSHIP PARTS DEPARTMENT ASK THEM LOOK UP WHAT AMP ALTERNATOR YOUR VAN USES MORE LIKELY 105 AMPS.

I would have the alternator checked. Sounds as if you are draining your battery completely down and the alternator is not keeping up.

The battery life is near its end too. It can be the alternator, jump start your car, and remove the jumper cables, if the engine cuts out it is the alternator. If it keeps goind for a while and the battery indicator light is off, it is the battery.

1- If the battery is old, some of the cells are dead then it can never be fully charged. 2- There is possible current leakage when the key ignition is out. Here is a check. 3- Take off the wire connection to the alternator. Take off the car key. Use a Multimeter set to current measurement To measure in series from the positive terminal of the battery to the positive cable. ( of course you have to take off the positive cable from the battery.) Your measurement should be less than 15mA, Higher than that you have shortage some where. Starting take off all fuses. one at a time to see the leakage measurement reduce to locate which path is leaking. 4- Keep the measurement set up like this, connect the Alternator wire inis place, look at the muleteer to how is the leakage current measurement. Sometimes the diode in Alternator circuitry leak allow the battery current flow back to the alternator causing battery current drainage. 5- Due to some work involved in testing to find out leakage current, You better be sure your battery fully charged to stay with statement the battery is really good but draining current because of some leakage.

I would start by scanning the vehicle for codes, if none are present i would check for fuel and spark and then check timing belt. It could be a number of reasons, check the above out and we can go from there.

I would check to be sure you do not have an internal short with in the alternator or accessory relay.