Electrical problems...

[scottb]

I hadn't driven my car for a couple of months, and didn't have it connected to the float charger. Battery was stone dead. I charged it up with a 6 amp charger for about three hours, and got enough juice to start the car. I then moved it into the garage and put it on the float charger for a week or so (it's the kind of charger that turns on automatically as the battery discharges and then back off when the battery is sufficiently charged).

I went to take the car for a drive yesterday, and found that the Clifford alarm didn't work. OK, I thought, either it just died or I killed it somehow when I charged the car. No big deal. So I took the car out and drove from my house to the coast -- about 40 miles. Everything seemed fine until the CD player started to skip, and then it died. OK, I thought, it's a lousy Blaupunkt and it died. I remember thinking, however, that it was strange that the radio would give me a problem at the same time as the alarm. So I continue on and everything looks fine -- no fluctuations in the tach, car has power, etc. I turn into the parking lot of a restaurant for dinner, and just as I'm pulling into a parking spot the car sputters and dies. I try to start it, and it's stone dead. Fortunately, I had AAA-Plus, and a flatbed came to take the car home.

So, it seems to me that I have a dead alternator, which is sorta surprising in that I replaced it about 10,000 miles ago (or less). The dead alarm keeps nagging at me, however. Could it be the cause of the alternator dying? Or, alternatively, could it not working (along with the dead alternator) be a symptom of a different electrical problem in the system. Or do I just have two unrelated problems that appeared at the same time?

The car is a garage queen. About 90,000 on the clock. No mods to the engine. The only electrical mods of which I'm aware are the alarm, Sucro headlight relays, a fuse for the front a/c blower, an fan for the extra front a/c condenser (fused), and a direct power line from the battery to the radio (fused).

Any thoughts on what might be going on here would be appreciated. Thanks, guys!

[911pcars]

On the most basic level, it could just be a case of the electrons not getting where they need to go due to loose, corroded or otherwise faulty battery/ground connections.

Other than that, it sounds like a dead battery caused by karma or simply bad luck, or a faulty alternator. While you had the battery on the charger for a while, it could still be a bad battery or a dead alternator. There are tests to isolate the cause.

Does the battery receive a charging voltage when the engine is running? Might be kinda difficult to test that if it can't start.

Many electrical accessories (alarm systems and sound systems alike) need a minimum voltage to operate. Lacking that, they won't. Make sure:

1. the battery can accept and hold a minimum charge level (>12.7 volts)
2. the alternator can recharge the battery at the correct charging rate (>13 volts)

Is the battery okay? Have it tested. You can't tell from an open circuit test without a test load placed on it.

Hope this helps a little. There's plenty of detail in the dead 911 archives.

Sherwood

[scottb]

Thanks, Sherwood. I'm going to try to charge the battery and see if the alternator is putting out. Given the way the car died, I strongly suspect a bad alternator. I'm just trying to figure out if anything other than the alternator is at fault.

[NineOhOne]

Bad battery.

[rick-l]

Originally Posted by NineOhOne

Bad battery.

+1 Take a trip to autozone and have them test it for you. (free). I suspect it has some shorted cells. Batteries don't like to sit around discharged.

[scottb]

Originally Posted by NineOhOne

Bad battery.

Why do you think that?

[rick-l]

Originally Posted by scottb

Why do you think that?

It may well be the alternator but you'll feel pretty stupid if you just change it out and then find the problem was the abused battery.

The symptoms do sound like the gradual discharge due to a bad alternator except for the alarm not working at startup.

[scottb]

Thanks, Rick!

[scottb]

Here's the latest:

I charged the battery overnight. It read about 12.8 volts after charging. I let it sit for an hour or so, and it read a bit lower, but not much. I started the car and, of course, it dropped due to the draw of the starter. I watched the volt meter as I revved the engine. Nada. Zip. It didn't move at all when I revved, and in fact it dropped a bit as the battery powered the various electrical bits in the car.

So, it's pretty clear the alternator is shot. I'll drop it off at the rebuilder this week. I'll also take the battery in to have it load-tested. If it's bad, too, I'll replace it.

Thanks for the help, guys.

[porschefool]

Exciter lamp in gauge blown? Bad regulator?
Just my .02
I actually get a kick out buying new batteries, massive new power and it's about the easiest thing to do on these things..
Then again, I pull spark
plugs almost as a nervous tic as well.

[scottb]

I took the alternator in for rebuilding. It should be done later today or tomorrow.

While I was there, I had them load-test the battery. It checked-out just fine, so maybe I dodged a bullet with the battery.

I'll hopefully have the car back together this weekend.