Battery problem or short somewhere?

[PaulRuffo]

This morning the engine wouldnt turn over. It would try, but couldnt quite make it. I rolled it backwards, popped the clutch and was on my way. I thought maybe I left something on overnight in the car. Got to work, turned the car off then tried to start it...same thing...wouldnt turn over. I put a meter on the battery - 10.4v. I figured the alternator may be on it's last legs, but still putting out enough voltage to keep the engine running. At lunch I took a friend with me to help push start the car to test the alternator. 14.65v, so it seems the alternator is functioning. Moved the car to a spot where I can roll down the hill and get home tonight. Car was running about 3 minutes. Turned it off and then for kicks tried to start it...cranked fine and fired right up. Turned it off and put the meter back on the battery...12.05v I turned the headlights on to see if they would **** the battery quickly and I watched on the meter...voltage started dropping off fast. Turned the lights off and was able to start the car, however it struggled to crank.

So, I am trying to figure out if the battery is not holding a charge like it should or if there is a short somewhere that ran the battery down and as a result the headlights drew the little charge I gave it away. The battery has given me no problems since I bought it 3 years ago. Even in below zero temperatures it would crank the engine with no problems. Does a battery just kick the bucket that quickly or do I have another problem.

Any insight would be much appreciated.

Thanks,
Paul Ruffo
94 mtx

<small>[ September 24, 2003, 01:04 PM: Message edited by: PaulRuffo ]</small>

 

[SHOZ123]

Depends on the battery, if there is a short any battery of any age will just go out.

What was the voltage when the car was running? With a good alternator and even a dead battery you should get over 13V at 1500 rpm. Unless there is a shorted cell.

A good battery, fully charged, at 75F temp, with no load and the engine not running should read about 2.10 volts per cell after sitting for 8 hours. If significantly higher than that the electrolyte is too concentrated due to low water level possibly. Of course if a cell is shorted it will be down by 2V.

<small>[ September 24, 2003, 01:12 PM: Message edited by: SHOZ123 ]</small>

 

[PaulRuffo]

With the car running, the voltage at the battery was 14.65.

When the engine is running, will the battery condition change the reading I get with the meter if the alternator is putting out a consistent charge?

 

[projectSHO89]

Stick a fork in that battery, it's DONE!

Steve

 

[PaulRuffo]

Thanks guys. I put a new battery in last night and this morning it still had it's charge, so no short in the car's wiring...just a bad battery.