Alternator not charging?

halistan · #1 08-29-2015, 01:19 PM

So, finally busted out the multi-meter to check my battery and alternator. Without a load (AC off, lights, radio, etc) I get 12.5v off the battery. Under a load it drops to 12.01. Then, when I get underneath (my alternator is now under the car with the supercharger) and check the alternator directly I also get 12.01v.

Shouldn't it be closer to 14.5? If I read this right (and I'm hoping you'll all tell me i'm wrong), I believe the alternator is undercharging which is why my battery keeps dying.

Anyone got any thoughts?

Oh, my alternator was rebuilt by Maniac and should be the high output version of 160A instead of 95A...in case that matters

Blacky · #2 08-29-2015, 02:04 PM

Yup, I usually look for around 14.2v.

92 SVX · #3 08-29-2015, 02:05 PM

Most definately should be more then 12.01v when car is running.

halistan · #4 08-29-2015, 02:15 PM

That's what I was afraid of. That's probably the root of the issues i've been having with the car and all these weird battery drains. I'll get underneath there and pull it off and take it to Maniac on Monday.

They closed today at 3pm and I was hoping to catch them and talk about it but i only got the answering machine each time I called.

Blacky · #5 08-29-2015, 02:53 PM

Give them #$%@ for everybody who had one fail lately. Seems like a lot!

halistan · #6 08-29-2015, 06:04 PM

Well, let's see what they can do to help first. I know some of the club members have spent many many years building a good relationship with Maniac Motors and I don't want to muck that up.

Christian is a nice person and I'm certain she'll do whatever she can to assist. I'm just worried that they won't be able to fix it since they can't get the parts anymore. Here's to hoping they have either found a new way to get them, or have some other option available.

svxcess · #7 08-29-2015, 10:05 PM

Ray,

I sent a voicemail and email to Christian telling her to expect to see or hear from you on Monday.

She could bench test it to see what's going on. Last time I talked to her she was still looking for another source for the voltage regulators. The original German ones seem to be unavailable.

She will do her best.

Ron Mummert · #8 08-29-2015, 11:11 PM

I recently replaced my original alternator with a NAPA rebuilt unit, & paid my local mechanic to get HIS hands dirty. The total was around 300 bucks to include a new belt. Cured all my drained battery issues. Period.

halistan · #9 08-30-2015, 09:52 AM

Quote:

Originally Posted by svxcess

Ray,

I sent a voicemail and email to Christian telling her to expect to see or hear from you on Monday.

She could bench test it to see what's going on. Last time I talked to her she was still looking for another source for the voltage regulators. The original German ones seem to be unavailable.

She will do her best.

Thanks

I appreciate you giving her a heads up. I'm hoping they can do something. At the very least maybe they can rebuild it back as a 95A and send me on my way. I would prefer the 160, but i'll take what I can get.

halistan · #10 08-30-2015, 11:12 AM

Got the alternator off, that was fun. First time I've ever had to remove a radiator in order to remove an alternator. Oh well, it is what it is.

Took it to O'reilly's to have them test it and confirm my own tests and their test showed less than mine did with the alternator putting out only 8.32 volts.

halistan · #11 08-31-2015, 11:08 AM

Update - I took the alternator by Maniac at lunch and they tested it. On their machine it showed that it was actually overcharging. He said that it was putting out 15.5 volts and was giving a diode warning.

His guess was that the regulator was bad and needed to be replaced. However, the good news is that he said "as of now" they do have a line on the parts needed to do the 160A build and could have it done within a day or so. That was good to hear and now I'm just waiting to hear back from Christian on if I had purchased the lifetime warranty with it or not.

I don't actually remember that being an option but if it had been I know I would have gotten it. Either way, it'll be good to have it fixed again.

fasteract7 · #12 08-31-2015, 03:00 PM

What was the explanation for you and the parts store getting low output but they (Maniac) getting 15+V?

halistan · #13 08-31-2015, 06:10 PM

There wasn't much of one actually. He said the regulator was bad as well as some internal diode. My assumption for the voltage differences is the speed the alternator was tested at. I tested it at idle speed, O'reillys machine barely spun at all, where the machine that Maniac put it on really spun it hard.

Without the regulator working to regulate that voltage it just gave off whatever was being generated at the speed it was tested at. That's just a guess though.