Nvncibl

I finally got time to look into what is draining the battery in my '94 90Q. I suspected the alternator, after 3 different batteries were tried and all died after a couple days of use. I pulled the alternator, which is a breeze with all of the AC parts removed, then had it tested at Autozone. It came back GOOD after a minute or so running on their tester. The tech seemed to know it would after about 20-30 seconds, because he said "It's gonna pass" and it did.

I got the alternator reinstalled and put in a good, charged battery to test her out again. This time I did an amp draw test but it came back clean, with just .049 amps. I double checked the connections, took her for a few mile test drive and retested with the meter. At this point, I was getting .047, which I figure is well within acceptable range.

So.... with no excessive amp draw, a working battery and a supposedly good alternator, where do I look next? Do I just drive it around for a few days and see if it dies again?

I'm thinking about running some voltmeter leads into the car, from the battery, so I can monitor the meter while driving, since our cars don't have a gauge for that. My thinking is that something is up with the alternator and that way I could see if the battery drops below 13v. Plus, it might help me get the car home before the battery starts to fade too far.

Any info will help. I already STFA and got nothing like my situation, so please don't flame if there is already a post on this. Just point me there and I'll be happy.

Thanks !!

Lago Blue

Here's a few things that are simple to do. Even without installing the meter to read while you drive, you could:

- stop the car and meter the battery with the motor running and not. Is it getting charge?

- are all the cable ends electrically clean? Follow the wires that cross under the oil pan too.

- are the alternator brushes worn down shorter and now weakly sprung against the armature?

- what is the highest voltage your battery will keep after being charged the day before off the car?

- What is the voltage on the battery in the car in the morning after sitting overnight after being driven long enough to be fully charged the day before?

- is the ignition switch / trunk wiring / cigarette lighter failed / failing and draining the battery while driving or when the key is out?

further reading on drains:

https://www.audiworld.com/forums/sho...hlight=battery