Voltage regulator troubles

Howdy all!

In the past I would do the ford voltage regulator modification to the 200 series alternators to produce a stable 14.7V. http://www.turbobricks.com/mods.php?content=art0004
However, my latest endover was plagued with a full fielding issue.
My last setup:
Volt meter on the battery (B+)
Volt meter on the wire to the brush (but left disconected) (VB)
30A variable voltage, variable amperage power supply. (PS)

Results:
Car off:
B+ 12.8V (who cares, 12 something)
VB 0V
PS 0V

Key to run (position II)
B+ 12.8V
VB 11.3
PS 0

Car running
B+ 12.8V
VB 11.3
PS 0

Then as soon as I get the power supply over about 1.3v (I haven't gotten a real number, but again, I am not sure it matters)
B+15+ and climbing
VB 0
PS numbers will match B+ despite having voltage and amperage set to 0

I got courageous (or dumb) and tried shorting the runaway brush (hooked to the power supply to ground) The whole car stumbled and I felt like I was about to discharge the entire battery in a very bad way.

Found that when the ford voltage regulator is hooked up it does the same thing and keeps the brush energized until you unplug it! (good way to drain your battery, too)

I am 99.99999% positive that the ford voltage regulator is hooked up correctly

I am on my second alternator and ford voltage regulator.

The stock voltage regulator that came with the new alternator is a normal voltage regulator, i.e. is ok until you start turning things on, like lights and the fan. With the highbeams on and the fan running full tilt I am getting .3V drop between the alternator case and the battery. Not great, but certainly not terrible either.


Has anyone run into this problem before? Any suggestions?

Thanks!

Andrew

I'm not sure what you are trying to measure or setup. I've never done the Ford mod because you can also get adjustable VR and high set point regulators for the Bosch alternators.

I've changed two of my cars to the Denso alternators with a 14.6 setpoint regulator in them.

I have tried several variable voltage regulators in the past, neither were particularly good.
do you have a part number for the better regulators?

14.7 volts is on the edge of boiling your battery, 14.2 is the normal. The amps that the alternator makes is more important.

283SD said:

14.7 volts is on the edge of boiling your battery, 14.2 is the normal. The amps that the alternator makes is more important.

Click to expand...

Maybe if you have an old style lead-acid battery. Modern AGM batteries prefer around 14.7v if you can get it and Optima lists a max recommended voltage of 15 for theirs.

I run my AGM at 14.6 to 14.7v.
Dave B

The new regulators I am referring to whether Denso or Bosch have a 14.6 set point. The Bosch one I use is made by HUCO. The Denso is generic. I just look at the venders for a 14.6 set point one for the volvo or denso part number on the alternator. There should be a small plate on there that gives you both part numbers and the rating.

I used an adjustable regulator for Bosch from DaveB above. I never had a problem with it.

I spent most of the day yesterday testing the and messing with the alternator. After too many trying to get the alternator to work in the car I made a test rig on the bench. Drill to spin the alternator, the car battery attached to the alternator (negative to alternator case, positive to battery terminal on the alternator). Then I used a variable power, power supply to energize the brushes. (negative to case, positive to other lead of brush pack.) When applying voltage you could hear (and feel) the alternator load up, but the output voltage would not increase. Do I need to also energize the dummy light terminal on the alternator? I can post a video later today if you all think that might help.

I also think I need to go through Dave's alternator page, make sure I am not missing anything there.

There is something about me that seems to cause volvo charging systems to hate me. I have tried the variable in the past, but always had good luck with the external... just not this time!

Andrew

Yes, you need to have 12v applied through a bulb to the D+ terminal to 'excite' the alternator into charging. If you want an easy test. Head to a local auto store like an autozone. They have an alternator test rig which also loads the alternator. With a load test you will know if there are bad diodes. Bring your external regulator so everything can be tested together.