Why is battery overcharging?

You need the charging system and the battery tested first, then if that is good you need the system tested for a current draw that exceeds 500 milli amps and 9 volts. Autozone and Advance auto parts do the battery and charging system test for free, the draw test will cost about 1 hour of labour.

It is called Battery Thermal Runaway. You are lucky that the battery did not blow up. You need a new battery.

It is caused by the battery charging itself and gets to a certain point and starts to over heat, melt, and blow up.

Overcharging, get alternator checked

Try starting the motor and then remove the negitive battery cable while running, If your car dies your alt. is bad. If your alt. was good it would be able to keep the engine running. Batteries are only for starting. If it stays running you might have a draw or short in the cars wiring and you would need a multi meter to check for draws. Or hate to say a shop. I hope this helps ya

Best way is to go to Autozone or Oreillys and get a free scan. They could also do a Starter draw test to see if it is okay.

The scan will tell you what the Code is for the Check light and Autozone or Oreillys can reset your Check light. If the Battery boiled away the water, then it is either overcharging or you have a high draw of current.

There use to be a test of taking off the Battery cable while the engine was running and if the Alternator was good your car would keep running. But with the new Electronics using this method may hurt the delicate Electronics somewhere else in the car.

Hi,

If the starter or solenoid clicks but nothing else happens when you attempt to start the engine, there may not be enough amps to spin the starter. Or the starter may be bad. A poor battery cable, solenoid or ground connection, or high resistance in the solenoid itself may be the problem. A voltage check at the solenoid will reveal if battery voltage is passing through the ignition switch circuit. If the solenoid or relay is receiving battery voltage but is not closing or passing enough amps from the battery to spin the starter motor, the solenoid ground may be bad or the contacts in the solenoid may be worn, pitted or corroded. If the starter cranks when the solenoid is bypassed, a new solenoid is needed, not a starter.
Most engines need a cranking speed of 200 to 300 rpm to start, so if the starter is weak and can't crank the engine fast enough to build compression, the engine won't start. In some instances, a weak starter may crank the engine fast enough but prevent it from starting because it draws all the power from the battery and does not leave enough for the injectors or ignition system.


If the lights dim and there is little or no cranking when you attempt to start the engine, the starter may be locked up, dragging or suffering from high internal resistance, worn brushes, shorts or opens in the windings or armature. A starter current draw test will tell you if the starter is pulling too many amps.


A good starter will normally draw 60 to 150 amps with no load on it, and up to 200 amps or more while cranking the engine. The no load amp draw depends on the rating of the starter while the cranking amp draw depends on the displacement and compression of the engine. Always refer to the OEM specs for the exact amp values. Some "high torque" GM starters, for example, may have a no load draw of up to 250 amps. Toyota starters on four-cylinder engines typically draw 130 to 150 amps, and up to 175 amps on six-cylinder engines.


Hope this helps,Good luck!!

450 out of 600 what? sounds like you have somthing drawing power need an amp meter. remove key and leave window down. disconnect negitive battery cable and connect meter between the negitive cable and negitive termainal on the battery should see around 2.5 milliamp draw or less may take 1/2 hour to get to this point. also if this vechile is not driven often this could be the problem

My 2002 GMS Sierra draws a simaliar amount of current.(.52 A). There a two items which draw current all the time on my truck. One is the OEM security system and I also have a wirless auto start unit. Both of these have a continouse draw on the battery. I've installed a high current marine battery switch to isloate this load if my truck will not be used for more than two weeks. Otherwise, the battery will be ecessivley drained. Regards, Jeff

It is not your battery overcharging it is your alternater putting out to much juice to the battery. get a new alternater