Hi all...I checked my charging voltage at the battery and it was high. It was almost 16.
So I went to install my spare and the regulator was very hot!! I've never noticed before because I never checked!! Should it be hot? I installed my spare and it allowed a charge rate of 13.4 but it also began to get hot.
Hope my alternator isn't bad!!
Cheers
Mike

13.4V is OK for charging, 16V isn't. It's going to be hot when you check it at idle because the regulator is running at a high duty cycle. I assume it's mechanical (i.e. original stock)? You might want to consider switching to a transistorized regulator, there's another thread going where this is discussed. If you're worried about your alternator, any reputable shop can check it in-car quickly by putting a scope on it and seeing what the output looks like.

Thanks Brad...I won't worry about it then.
Mike

Wont worry? 16 volts is too high. You will ruin the battery not to mention the rest of your electrical system. Get a new regulator

I think he was talking about his spare which was charging at 13.4V when he said he "won't worry".

To clarify, I switched to my spare regulator that allows a charge rate of 13.4 volts. When I said I "won't worry", I meant I won't worry about the regulator getting hot!!
Thanks all...
Mike

Ok Sorry. I somehow missed that.

It wouldn't be a bad idea to have your alternator checked out, have a tech put it on a scope and see what the output looks like. Without being there, it's hard to know how hot your regulator is and if it's working correctly. Considering the hassle of replacing an alternator and the cost, investing in a few bucks to make sure it's OK makes sense. If you have an oscilloscope or access to one, you can check it out yourself, there are a lot of guides how to do this on the web, that show representative waveforms of what the output should look like.

Before doing anything else, lift your relay board and look at the underside. The tar sealing can and will melt away which leaves the receptive electrical contacts inneffective. I had the same over charging problem, replaced relay board, all fixed!

If you're concerned it might be the relay board, then simply remove the VR off the board, disconnect the alternator harness off the board, and plug it directly into the VR. Plugs right in.

http://www.914world.com/bbs2/index.php?sho...=292455&hl=

Thanks for the link!!

Mike, if you do remove the VR from the relay board, do NOT relocate it to sheet metal in the car and screw it down. There's a reason that Porsche attached the metal case to the plastic side of the relay board, they didn't want you to ground the VR case. Flip it around like it was shown in the link.

From my posting in 2007:

"As I said earlier, it looks like I have an alternator ground strap fault. If you have a similar fault, and add a ground wire between the VR case and ground, then ALL OF THE CURRENT SUPPLIED BY THE ALTERNATOR WILL FLOW THROUGH THAT JUMPER WIRE. It could easily exceed 20A, and could start a fire.

Bosch and Porsche must have recognized this potential problem and decided to let D- on the VR case float. That way, if there ever was a ground fault, you wouldn't have an unsafe ground current path. I should have known that this wasn't a design flaw - it was actually a safety feature. Smart guys, those Bosch and Porsche dudes."

Like I suggested then, any time you suspect you have a charging system problem, check to see if you have a poor alternator ground. Many cars lack any kind of alternator ground strap, and the only ground path is through the corroded hinge.

Thanks Brad...is the alternator grounded at the relay board?
Or are you saying I should add a ground somewhere?
Mike

Answered in PM. Alternator should have a ground strap, if there isn't one present, use 8 gauge wire and make one yourself, bolt to alternator and to chassis. Do NOT ground the voltage regulator at the relay board, because if there is a poor alternator ground, you'll get a significant current through the D- wire in the alternator harness and possibly melt it or start a fire. Do NOT mount the voltage regulator on to a chassis surface!!!