Battery not charging, Voltage regulator issue?

[shu513]

Hello. This is my first time posting, and I'd really appreciate your suggestions!!

My car is 64 Notchback converted to 12v system, and located in Japan. I have this car for 3 years, and never had charging problem until this time.
We had pretty heavy rainy season this year. I started the car when it was sunny, and the Generator Control Light on the fuel gauge unit came on and stayed on. I was just thinking that the humidity is messing with the connection somewhere, so I kept the engine running for a while to warm up and dry the system. (I don't really know if it really works or not...) After a few minutes with revving the engine up to 2000 rpm or so, the light went off, thinking everything is ok now. A week later, I started the car and the warning light stayed on and never turned off.

So, I started checking from the generator. I have 90mm small 12v generator, so I was really hoping that the problem is not the generator itself. By checking the output of D+, it was putting out more than 30 or 40v as rpm gets higher. The brushes are good. The battery measurement is 12.7v without running the engine, but it did not change with the engine running. I checked wire connections and tested with multimeter to make sure I have good connections and ground. After all those tests, I came to a conclusion that my Bosch solid state voltage regulator went bad (maybe with high humidity...), so I replaced it with new one. It worked! The light came off and the battery was charging almost 14v for about 30min of running time... then the generator light came back on. I tried revving it up hoping for it to turn off, but it didn't. I repeated the whole testing procedure again, but everything seemed ok, the same as before changing the VR. The car starts fine and runs good.

Could this new VR be the problem? Did I get a bad VR? Or is something causing the VR to go bad?
Should I get it replaced with new one?
Could it be something else?

I really appreciate your help on this issue.

Thank you in advance!!!

[VWporscheGT3]

SHU,
check your brushes. they might be sticking or completely worn out if they are flush with the notch for the spring then they are done/ worn out. the symptoms you are describing remind me of when I first experienced this.
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Push down on the upper brush with a screwdriver while it is running & it will make the light go out?
New brushes are only $1.50?
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[Bobnotch]

And if replacing the brushes doesn't fix it, it's replace the voltage regulator time. BTDT.
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[shu513]

[shu513]

So here is the wiring I checked so far.
The brushes are good and they are above the top of holders. The generator tests were performed according to below sites and passed.
http://www.vw-resource.com/generator.html
http://speedyjim.net/htm/gen.htm

The car starts and runs great, and head lights, turn signals and others do work fine. So the only think I can think of was VR. The first replaced VR worked for a little, but stopped working. The second one does not work at all... Could it be bad ground on VR and/or Generator?
I believe the ground wire from generator is connected to VR for better grounding on newer models. Should I get a jumper wire from D- on gen to VR base where attached to the body for better grounding? Or should I add another jumper wire from VR base to - on battery?

[Multi69s]

Its been awhile since I have used a VR, but the first thing that popped into my head was the grounding of the VR itself. I would try running a wire to the battery itself, since this would eliminate any other bad connection.
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[shu513]

[shu513]

Here is quick update.

I checked the ground on VR and it was good. The test light came on at the VR base. Still the generator light is on and no charge at the meter.

So, I re-measured the voltages at below conditions.
Without Engine Running:
12.6 ~ 12.7v @ Battery

With Engine Running:
Point A: 12.4 ~ 12.5v @ Battery, No voltage increase with higher RPM.
Point B: 12.4 ~ 12.5v @ VR B+ and Battery -, it goes up to around 14v with higher RPM.
Point C: around 2v at VR D+ and Battery - (don't know what it really means...)

The voltage increases at point B, so I believe that means the charging system is working, correct? The cable between battery + and VR B+ was recently checked for continuity and was ok. My battery has never been changed since I have the car for little over 3 years. And I believe it was on the car before I got this car. I only drive this car occasionally on weekends.
With above statement, could it be that my battery is too old that it is not accepting the charge? I remember my external battery charger stays at 90% after more than 10 hours of charging time, and never go up to 100%.

I really hope this battery is the cause and replacing with new will solve this whole issue.
Could you please share your thoughts & opinions, and direct me to the right direction?
I don't want to go out and spend unnecessary money on parts...

I really appreciate your support as always.


UPDATE July 20th 10:30 am

So, it's always the most simple idea to lead to the conclusion. I ran a ground wire from Generator Body D- to the base of VR to share the ground. It worked!! It turned the generator light turn of @ higher RPM around 2000 rpm with about 13.7v on volt meter!!!

Thank you all for your kind suggestions. I learned so much about the charging system this time.
I really appreciate your support!!