| Author |
Message |
bastardbus
Samba Member
Joined: July 13, 2000
Posts: 1768
Location: Toledo, Ohio
|
 Posted: Sat May 15, 2021 4:14 pm Post subject: Bosch Solid State Generator possible over charge situation |
 |
|
`66 Single cab, 1600 sp converted to 12V 30A gen. Installed a new modern solid state Bosch Voltage Regulator couple years back, has been working fine or so it seems. Was doing some routine maintenance and had my meter out today. For shits and giggles checked the DC at my battery terminals while engine was running. While at idle I was 14VDC and at 2-3K RPMS she jumped up around 17VDC. I am used to 12.6 at idle and 14VDC ish at speed when using the old original style voltage regulators. Everything "seems" to be fine but those higher numbers seem out of the ordinary to me and thought I would check with you folks if this is something common to the newer style SS regulators or there is a problem I should address.
_________________
Samba Member #95 |
|
| Back to top |
|
 |
telford dorr
Samba Member
Joined: March 11, 2009
Posts: 3551
Location: San Diego (Encinitas)
|
| Posted: Sat May 15, 2021 5:23 pm Post subject: Re: Bosch Solid State Generator possible over charge situation |
|
|
Unplug the regulator and see if the problem stops. If so, failed regulator.
Also, check the meter on another vehicle to rule out meter issues.
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST) |
|
| Back to top |
|
|
bastardbus
Samba Member
Joined: July 13, 2000
Posts: 1768
Location: Toledo, Ohio
|
| Posted: Sat May 15, 2021 6:46 pm Post subject: Re: Bosch Solid State Generator possible over charge situation |
|
|
| telford dorr wrote: |
Unplug the regulator and see if the problem stops. If so, failed regulator.
Also, check the meter on another vehicle to rule out meter issues. |
Meter is perfectly fine it is a fluke 87V and was tested on my sons ghia same time. Ghia was 12.6 to 13.7 VDC idle and full rev where it should be. The bus is like 14V idle and almost 18V at full rev when I went out later tonight.
Unplug the regulator? There are various ways and methods to testing the gen and reg separately. What method are you suggesting and outcome I am looking to find?
I have an old analog bosch unit I will swap in place tomorrow but figured I would ask this tonight see if anyone has had similar issue with these SS units.
_________________
Samba Member #95
Last edited by bastardbus on Sat May 15, 2021 8:03 pm; edited 1 time in total |
|
| Back to top |
|
|
telford dorr
Samba Member
Joined: March 11, 2009
Posts: 3551
Location: San Diego (Encinitas)
|
| Posted: Sat May 15, 2021 7:46 pm Post subject: Re: Bosch Solid State Generator possible over charge situation |
|
|
| Quote: |
| Meter is perfectly fine it is a fluke 87V and was tested on my sons ghia same time. Ghia was 12.6 to 13.7 VDC idle and full rev where it should be. The bus is like 14V idle and almost 18V at full rev when I went out later tonight. |
OK, just a sanity check. Avoids a lot of false diagnostics...
| Quote: |
| Unplug the regulator? and what do say that should show regarding the regulator? With no regulator you will get 12V at idle then a steady climb up into 30-40V (and fry it if you don't shut it down soon enough). |
The battery voltage should not climb at all, as there is no regulator to pass generator field current. If you do get output, then it means that there is a fault in the generator (grounded Df terminal), or a short in the harness to the regulator (assuming everything is wired correctly)..
| Quote: |
| The gen is working putting out enough VDC the reg is what is controlling what is seen at the battery. |
Not at the battery - at the voltage at the B+ regulator terminal (although they should be the same...)
| Quote: |
| This regulator is "functioning" but how correctly is the question because as it is running higher then I am used to. Just curious if others have seen this high voltage readings from these SS units. You used to be able to tweak the old relay style units for more or less output. |
A typical failure is a shorted regulator field driver transistor, which would cause the regulator to run 'wide open'.
| Quote: |
| I have an old analog bosch unit I will swap in place tomorrow but figured I would ask this tonight see if anyone has had similar issue with these SS units. |
Good idea.
The only issue I have with the SS units is that the case has battery voltage on it, and if you accidentally short it to ground with a tool, then you get an impressive shower of sparks and flame. Surely they could have included a vented plastic cover or something... (maybe a 3D printer project?)
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST) |
|
| Back to top |
|
|
perello
Samba Member
Joined: April 15, 2005
Posts: 829
Location: where social security comes for free
|
| Posted: Sun May 16, 2021 2:31 am Post subject: Re: Bosch Solid State Generator possible over charge situation |
|
|
Just checked mines with a fluke 175
- vw 181 38A gen,ranges from 12.5V idle to 13.6V
-bus 90mm 25A gen, from 12.2V to 13.8V
_________________
Aug '58 pressed bumper SO23
1974 German Thing
1978 Bug 1200 |
|
| Back to top |
|
|
bastardbus
Samba Member
Joined: July 13, 2000
Posts: 1768
Location: Toledo, Ohio
|
| Posted: Mon May 17, 2021 12:40 pm Post subject: Re: Bosch Solid State Generator possible over charge situation |
|
|
So indeed the Voltage Regulator was the issue. It was one of the new Bosch Solid State units. Sure did not last long  I replaced it with a used old Bosch relay style I had in storage. Worked perfectly.
Oddly enough a check of my son's ghia came up with a bad VR as well. It was a no name old relay regulator though this one was slightly undercharging. He had noticed a sluggish battery lately, so we checked it this weekend and also replaced that one with a used old bosch relay unit as well and she is up and working where should be too.
Two VRs in one weekend...and now down to only 1 spare old style bosch regulator left.
_________________
Samba Member #95 |
|
| Back to top |
|
|
perello
Samba Member
Joined: April 15, 2005
Posts: 829
Location: where social security comes for free
|
| Posted: Tue May 18, 2021 11:37 am Post subject: Re: Bosch Solid State Generator possible over charge situation |
|
|
just checked and the 181 one is 6 years old...how old was yours?
_________________
Aug '58 pressed bumper SO23
1974 German Thing
1978 Bug 1200 |
|
| Back to top |
|
|
|
