prjct337

My 87 5KSQ runs perfect. Just fixed the knock sensor. But the battery will not stay charged over night. If I leave the battery hooked up...the car will only give me one crank till its dead. The battery is new and when I charge it it charges in about 1 minute. Any Ideas?

4Driver4

You have a current draw somewhere. Aftermarket radio? Trunk light?

rooster 2

try another charger, or like 4Driver4 says, start looking for current draws.

If you drive for quite a while (at least 30 minutes), the alternator should recharge the battery. When you do that, does the battery hold a charge over night?

5000CDQturbo

new batterys are known to fail ...

Suffolk

Battery bad?

SUPER HIGH resistance in the wires to start the car?

If it dischanges quick and only takes 1 minute to charge the plates are shorted inside the battery IMHO.

Is there ANY water inside the battery.

Its RARE but my motorcycle battery needed a chemical added to it, it came DRY. Auto abtteries usually ready to go but check the water level............

-Scott by BOSTON

audijim113

Not that the physical size would make a difference electrical, but if you didn't get a short, squat one, the terminals could be touching wire spring stuff under your seat.

Mister Bally

I one time had a bad alternator on my '87 5000CS tq which caused a high current draw. It discharged the battery in about 48 hours.

I verified the draw with a current meter at the battery. But finding the culprit was not easy. The car was garage kept. One morning I decided to lay down and touch the alternator. It was toasty warm. I guess it was a leaky diode. The idiot lights and Auto-Check worked fine. The alternator still charged the battery. The problem was if the car sat for more than one day.

Try the alternator touch test. It is free!

prjct337

Thanks for the ideas...I am going to look at a couple of things. I'm going to disconnect the aftermarket radio (was installed when I bought the car...I didnt put it in).

SF200TQ

I had a battery drain problem, too. I thought (thought) the aftermarket deck was turning off correctly, as it seemed to power down when I turned the car off. So, I taped up the trunk hinge wires, took apart the door wiring, etc etc etc (all good recommendations, of course) and still had a draw.

Turned out the "professional shop" that installed the expensive deck for the previous owner had not bothered to find a keyed ignition connection... the "off" on the radio was still drawing enough to run the battery down. Rewired it correctly = battery draw gone.

Just my $0.02, but since the Audi radios originally don't turn off completely with the key (iirc), I bet this is a likely problem?

SF200TQ

Errm... make that "radio" not "battery" = damn 60+wpm! : )