Dead battery
Thread Starter
Drifting
Joined: Jan 2001
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From: Mickleton NJ
Dead battery
I put new battery in my 87 in Dec. Haven't sarted it a a couple of weeks , went out to start dead. I recharged it, but is the C4 like the C5 , where the computer runs , when the car is off. Is there something draining the battery, if so how do I check, thanks in advance Jim.
Team Owner
Joined: Aug 2000
Posts: 40,156
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From: San Pedro CA
the best bet is to put an amp meter on the battery and see where the draw is.
the alarm does stay on, so that does suck down about .25 amps - I just don't remember the time of that draw.
if you are not going to drive the car on a daily basis, I suggest you get a battery tender, which will keep the battery charged when the car is not in use.
the alarm does stay on, so that does suck down about .25 amps - I just don't remember the time of that draw.
if you are not going to drive the car on a daily basis, I suggest you get a battery tender, which will keep the battery charged when the car is not in use.
Le Mans Master
Joined: Jun 2006
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From: One day you're a Comet...the next day you're dust... Arkansas
Originally Posted by Jim D
I put new battery in my 87 in Dec. Haven't sarted it a a couple of weeks , went out to start dead. I recharged it, but is the C4 like the C5 , where the computer runs , when the car is off. Is there something draining the battery, if so how do I check, thanks in advance Jim.
Team Owner
Joined: Mar 2001
Posts: 54,124
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From: Cincinnati, Oh USA
Lead acid batteries do not like sitting doing nothing for long periods (4+wks) and they self discharge even disconnected as much as 1% each day. During discharge they collect lead sulphate on the plates and if left there it gets hard and won't convert back to lead and sulfuric acid like it does when you charge it regularly and while the lead sulphate is soft. A fully sulphated battery is a door stop and repeated full discharge and recharge reduces the amp-hour capacity of the battery and soon you effectively have a motorcycle battery.
You should first charge up your battery with a charger and then disconnect the neg batt cable and place an ammeter from batt post to cable lug and after the courtesy lights time out, measure the leakage current. GM says it should not exceed 50 milliamps. My 87 draws 27 ma. If you have excess leakage current, then you need to find out which circuit is the cause. First at night check for underhood lights, vanity mirror lights, door panel map lights, console light. Do you have a radar detector, aftermarket alarm, radio, or audio amp? Check em. You can pull fuses one at a time and watch the ammeter to find the circuit.
I too recommend you get a battery tender to keep your battery up, lead acid batteries go dead when not used!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
You should first charge up your battery with a charger and then disconnect the neg batt cable and place an ammeter from batt post to cable lug and after the courtesy lights time out, measure the leakage current. GM says it should not exceed 50 milliamps. My 87 draws 27 ma. If you have excess leakage current, then you need to find out which circuit is the cause. First at night check for underhood lights, vanity mirror lights, door panel map lights, console light. Do you have a radar detector, aftermarket alarm, radio, or audio amp? Check em. You can pull fuses one at a time and watch the ammeter to find the circuit.
I too recommend you get a battery tender to keep your battery up, lead acid batteries go dead when not used!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
