I have a charging problem - and I did a search

[Kidasters]

So - no kittens were sacrificed.

I try and start the car at least once a month, just to make sure the fluids circulate. Started it a few weeks ago, at night, and turned on the A/C. Don't know why, just playing around. Well - voltmeter starts reading about 11.5 volts. Not good. Cut off the a/c and lights, and only saw 12.5 volts at 2000 rpm. Now - years ago, I pulled the stock alternator, and I'm running the 85 amp E-bay alternator. I know there have been posts that people have been having problems with these, so I figure I'd swap it.

Thanks to Blunt, I have an E21 65 amp alternator in place now. Got everything put back together tonight, and started the car. With nothing on, just the car running, I'm reading 12.9 volts on the voltmeter in the car and at the alternator with my hand held voltmeter. With a/c and headlights on, I'm back below 12. The biggest drop happens when I turn on the A/C fan.

Not good.

Tomorrow, I think I'm going to re-do the ground off of the alternator (right now, it's where the stock unit was grounded - on a bolt near the carb on the intake manifold).

Any other thoughts? Besides "Don't turn on the a/c fan".

Thanks,

Ken

[Otis]

Yup - Going through the same thing right now. Suggest you call Darren at Rush Power Systems. Tell him I sent you.

www.rushps.com

Just tell him you're having the same problem I was having, but that you don't need to build an attack-Russia-sized alternator like mine. BTW, I went through all the ground-wire stuff, and for over a year drove myself crazy with the voltmeter. As Darren will tell you, it's usually the regulator.

[Kidasters]

you think it's the regulator Otis? Brand new alt?

Or maybe it just can't keep up with output?

BTW - just changed the ground on the alt to a known good grounding spot. No change.

Crap.

Ken

[ifayeoh]

What voltage when you rev the engine?

there should be a drop in Volts, especially if just idling, AC takes some current and so does the fan in front of rad and the blower in car.

Now if you are at speed and turn on and see drop then you have a issue, but what you are seeing is SOP.

[Otis]

you think it's the regulator Otis?

According to Darren, the alternator had a coating on it. That caused heat retention. Thus, everything fried. Alternator went bad, regulator went bad. So I was running off the battery (which I was religiously recharging) and the voltmeters were showing 12, surging when I rev'ed the engine or hit speed. That's because the alternator was still putting out a small amount of current - just not enough to keep everything healthy.

The new alternator will have a special coating on it, to help dissipate heat. I will cut-and-paste (in a future post here) Darren's exact technical diagnosis (I'll ask him to summarize it for us, and I'll post it here).

Give me a little while - I'll dig up the exact diagnosis on the regulator. Will keep you posted.

Again, you have the EXACT same problem that I had, from your description. You might recall my "red light" thread from about a year ago - the alternator had just enough current to keep me fooled into thinking everything was okay. It was not.

[Kidasters]

Thanks Otis. Just tell them "Otis sent me?".

Plus - if you don't mind me asking - what are you paying for your system? You didn't do a 300 amp dial-a-voltage system for a few grand did you? Yikes!

Thanks again.

Ken

[Otis]

No, it's not that much. Had I just rebuilt the Streetwires alternator, it would have been about two hundred bucks or so. But the thing was too far gone; it works now, but for my application, it would not be reliable. A normal alternator is not that much from Darren. My new one will be extreme (surprise, surprise) - but all things considered, quite reasonably priced (I was pleased with the price - Darren gave me several options, and I chose the most extreme one).

Yes, tell him that Otis sent you - he is familiar with the FAQer board.

By the way, Darren and I are trying to figure out what to do with the Streetwires alternator. He rebuilt it, but he cautions against relying on it ("it's old technology"). You can try it in your car, if you'd like - I owe him for rebuilding it, but we're trying to determine whether simply to canibalize it or donate it to a worthy cause. For a stock application, it's overkill (which is a good thing, provided you match the regulator). For my system, however, it's not useable, and thus, is a really fancy paperweight.

[stultis]

I would go through and check the ground cable and ground connections. On the 72 I am helping restore, the lights were very dim at there brightest. I went in and cleaned all the ground connections and cables. It was amazing how simple of a fix this was. The headlights did not pulse nor do the dash lights. Also the checked the reading on the alt. It was perfect.

Just use a really good scuff pad on the terminals, and 100 grit on the end of the ground cables to the body/motor.

[Kidasters]

Here's what he said:

I am happy to help you with this, here is what you are dealing with. An AC

system will pull between 20 and 30 amps, lights are about 10, ignition is

about 10 and the fog lights are about 10 so that is around 60 amps. The

manufacture counts on the fact that you will not spend much time with

everything on at once. But here is the problem, the stock 55 amp alternator

will only do 55 amps at about 3500 RPM, at idle it is more like 10 to 20

amps, so you are running off the battery at low rpm.

I'm talking to him about a custom alternator (100 amp - 65 am at idle). We'll see what happens.

Thanks again for giving me the contact to Darren.

Ken

[jgerock]

Reading thru these posts confirms why my car needs to be kept on the Battery Tender while I'm not driving it. The battery will accept a charge even after a 1 hour medium-to-high rpm drive (since I'm still using the stock tii alternator & regulator and I don't have a mega-watt stereo system).

[kcdonahue]

I'm running a 130 amp (upgraded) e30 alternator in my tii for just this reason...

I started out with a 55 amp e21 alternator, when that didn't cut it I upgraded to a 65 amp (may be e21...) gave it a few months and took some measurements while my car was connected (not running) to my big external power supply that I used for car audio competitions back in the day and came to the conclusion that 65 amps was not enough for my car.

I also upgraded my power and ground cables and used high quality terminals and crimpers all around... 2 gauge from the battery in the trunk, 2 gauge ground at the battery. 8 gauge from the alternator to the bulkhead power distro point where the 2 gauge ends, and 8 gauge ground from the alt to the block and the body.

I likely have more then I need but I'm ok with that.

KC

[Kidasters]

OK guys - I'm working on a solution with Darren at Rush Power Systems. It will be similar to what Otis has going. I'm going to send Darren an alternator mounting bracket for a 2002 (sorry Otis - I couldn't remember if you had a Tii or a normal 2002), as well as an alternator, so that we can come close to stock size and mounting. He's going to make me an alternator that is 100 amp, 65 amp at idle, with heat reducing coating, and some new leads (with fuse) to tie back into the harness and the main ground. I know I could have probably gone the E30 route - but being able to keep the stock mounting makes this kind of intriguing.

Here's our starting point:

I will keep you all (if you are interested) in the progress.

Later,

Ken

[Kidasters]

Well - I talked with Darren today. Here's where we are at.

I sent them the "85" amp alternator that I had purchased off of E-bay for two reasons. First - to see if an alternator they had in the shop would fit or if I needed a "custom" alternator. Second - I wanted him to test it so that I could understand output.

He has this alternator, and says that the one he was planning on me using is a "bolt in" replacement. Perfect. So - I'm getting a 100 am alternator (more on that in a bit), coated with a heat reducing coating, and a new lead to go to the battery/tie into the harness.

Second - he tested my current "85" amp alternator. And here's what he came up with:

"It is a 85 amp alternator but it will not do 85 amps until about 4500 RPM,

another problem is the alternator is only about 65 amps when hot.

Alternators loose power when they heat up so there is two ratings for

alternator, one is when hot and the other is when cold, the problem is both

ratings are used in the industry. We rate our alternators hot because it is

more accurate, so a 100 amp alternator is actually 130 amps cold. So if we

were to sale the alternator we would list it as a 65 amp or an 85/65

alternator. "

And - we all know it's never hot in Texas.

So - hopefully we'll see the new 100 amp alternator soon. We'll see.

I'll post another update when I get it together.

Ken