brooks944

I drove my '85 Carrera 911 FTL on Monday and Tuesday to work, about 30 miles each way and everything worked great. Today when I went to start it, there was no electrical at all. What would make the battery die so quickly, did I leave something on? I've had it on a trickle charger today for several hours and it did start but I'm puzzled what caused it to die. It's an interstate battery that came with the car, which I've had for about a year. Any ideas?

Thanks,
Rick
'85 911 Carerra FTL
'86 951

theiceman

lots of em....

measuer the voltage at the car while isdling .. what do you have for voltage .. what do you have at about 1500 rpm ?

do oyu have an after market allarm ?
did you discomnnect the battery and hook your multimeter between the battery lead and the battery with the car off ? set to measure current ( amps ) .. what did it read ?
do these tests and come back and we will be in a much better position to help .

brooks944

Thanks iceman. I have some answers, but not all. Took the car to work today, started and ran fine (I go in early, got there about 5:15 am). When I went out at lunch to check if it would not start. Got it boosted and to Autozone where they did a check and said the battery was fine, just needed charging. My wife and I did some testing when I got home, all numbers after being on a trickle charger for about 1.5 hours:

Volts = 12.40V
While idling = 13.81V
At 1500 rpm = 13.85V
After turning the car off = 12.62V
After restarting again = 13.83V

I don't have an aftermarket alarm, and didn't disconnect the positive terminal to test, did do the negative side and it was consistent with the #'s above. I did notice the negative side was looser than I would set it and tightened it more when I put it back on. Does this info help diagnose, or was the negative too loose?

Thanks again,
Rick
'85 911 Carerra FTL
'85 951