Battery Dying While Car is Running
#11
08-04-2008, 11:08 PM
You just reinforced my statement thanks.......if you read all of my posts I clearly stated step by step what should be done !!!
Q: My minivan has failed to start a couple of times recently, because of a low battery. It turns over, but won’t spin fast enough to catch. My mechanic says he tested the battery and it’s bad. But it’s only a year old. I checked the voltage at idle, and it’s 13.8 volts. All of the cells have plenty of water. I think it’s something else.
A: There’s more to checking a battery than testing the voltage and looking inside for low water. For one thing, you need to check the voltage when the engine is off, not when the alternator is raising system voltage to its normal level. You can test for proper cranking voltage with a voltmeter while—you guessed it—cranking the engine. The several hundred amperes of current the starter motor draws should pull the battery voltage down to a normal 9 to 10 volts. Do this test: Disable the ignition or injection to prevent the engine from starting. Then put a voltmeter across the battery posts while cranking it with the key or an external remote starter button. Crank for 15 seconds (no longer); the battery voltage should remain 9.6 volts or above. (These are GM specs for a battery at 70 F; your mileage may vary.)
But then again these are GM's specs......9.6 volts is too low and at that voltage the car wont start !!!
Q: My minivan has failed to start a couple of times recently, because of a low battery. It turns over, but won’t spin fast enough to catch. My mechanic says he tested the battery and it’s bad. But it’s only a year old. I checked the voltage at idle, and it’s 13.8 volts. All of the cells have plenty of water. I think it’s something else.
A: There’s more to checking a battery than testing the voltage and looking inside for low water. For one thing, you need to check the voltage when the engine is off, not when the alternator is raising system voltage to its normal level. You can test for proper cranking voltage with a voltmeter while—you guessed it—cranking the engine. The several hundred amperes of current the starter motor draws should pull the battery voltage down to a normal 9 to 10 volts. Do this test: Disable the ignition or injection to prevent the engine from starting. Then put a voltmeter across the battery posts while cranking it with the key or an external remote starter button. Crank for 15 seconds (no longer); the battery voltage should remain 9.6 volts or above. (These are GM specs for a battery at 70 F; your mileage may vary.)
But then again these are GM's specs......9.6 volts is too low and at that voltage the car wont start !!!
#12
08-04-2008, 11:12 PM
im sorry ghetto i didnt read you post the whole way, i misread it thinking you were just saying to test it while it was off. No hard feelings?
#16
08-04-2008, 11:21 PM
patent law makes more money and is fun. Im interning outside of dc and making 180k as an intern. Seems hard to believe but i helps that the partner in the firm happens to be my best friend from high schools father.
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