MC8 Alternator overcharging

[quantum500]

Was well over 40v before I caught it.  Seems to have burned up parts of the voltage regulator a couple resistors look pretty toasty diodes seem to be ok??  So what's up with that?  I have not checked anything in the alternator. What do I need to check before I get a new voltage regulator? Where is the best place to get a voltage regulator?  Thanks in advance.

[Tom Y]

500, I don't know what caused it but I have one from my MCI. It should be worth 20.00 + shipping if you are intrested. It was working when I removed it.  Tom Y

[gumpy]

I guess I'd go through the manual and perform the checks it outlines on the alternator itself, or I'd have a qualified alternator or bus mechanic do it for me.  When my alternator when south a few years ago, it also took out the regulator. I replaced it with a new solid state regulator. Had to run a new wire direct from the batteries, but it's been very stable since.

Check your wiring connections at the alternator to make sure they are tight and well made. Loose connections is what took mine out.

[quantum500]

500, I don't know what caused it but I have one from my MCI. It should be worth 20.00 + shipping if you are intrested. It was working when I removed it.  Tom Y

I'm interested.  Shipping Zip 81425.  Let me know how you want paid.

[quantum500]

I guess I'd go through the manual and perform the checks it outlines on the alternator itself, or I'd have a qualified alternator or bus mechanic do it for me.  When my alternator when south a few years ago, it also took out the regulator. I replaced it with a new solid state regulator. Had to run a new wire direct from the batteries, but it's been very stable since.

Check your wiring connections at the alternator to make sure they are tight and well made. Loose connections is what took mine out.

I'm just getting to that point.  From what I know it is probably a diode in the alternator that is causing problems.  I talked a friend of mine that is a trucker.  Back in the day they used to run quite a few detroits with those gear drive alternators on them.  He was not a big fan, seems they had all kinds of trouble with diodes going out and over charging the system.  He eventually went to a single wire belt drive set up.  I'll fix it this time and if it does it again its getting taken out.  I could get along just fine with 150amps.

[Tom Y]

Does this look like yours? Would you want the whole thing shipped or just the board? I think it unscrews.  TomY

[quantum500]

Yep that looks like the offending part.  You can just ship the whole thing.  Check on a flat rate box at the USPS see if its any cheaper.  Thanks Tom I appreciate the help.

[Tom Y]

500, If you want I will send out in the morning. Let me know. Do you want priority USPS or the cheapest way possible? You can send me a check after you get it or Paypal me if you are able. Thanks Tom

[TomC]

When I had my 50DN Delco rebuilt (actually they exchanged it) I also bought a new regulator, even though the one that's like the picture still worked.  I wanted to change it out since I got headlights that flickered with the voltage going up and down.  The new voltage regulator is about the size of a deck of cards, is still adjustable and has cut the flickering at least in half since it is more accurate.  Highly recommend the change.  Good Luck, TomC

[quantum500]

500, If you want I will send out in the morning. Let me know. Do you want priority USPS or the cheapest way possible? You can send me a check after you get it or Paypal me if you are able. Thanks Tom

You can just go the slow route.  I have paypal if you want to send me your e-mail address.

[quantum500]

When I had my 50DN Delco rebuilt (actually they exchanged it) I also bought a new regulator, even though the one that's like the picture still worked.  I wanted to change it out since I got headlights that flickered with the voltage going up and down.  The new voltage regulator is about the size of a deck of cards, is still adjustable and has cut the flickering at least in half since it is more accurate.  Highly recommend the change.  Good Luck, TomC

Thats a thought.  Do you have a part #?

[Tom Y]

Would you like me to wait a couple days to be sure? Its no problem.  Tom Y

[quantum500]

I have a new angle I'm going to take, but that post about the new regulator got me started.  In the aircraft industry they use voltage sensors on the charging systems so if you get a over voltage situation it basically turns the charging system off.  Although I haven't found the exact part I'm after I will and I can use your old regulator just fine.

[Sojourner]

For factory replacement to update charging performance such as optional “sensing” wire to optimize the state of charge. This small gauge sensing wire is only for voltage signal purpose…from + battery post to 50VR sensing post.

Delco Remy 50VR 10503805….Solid State 24v neg. ground voltage regulator
http://item.express.ebay.com/VOLTAGE-REGULATOR-DELCO-REMY-10503805-model-19020411_W0QQitemZ220258007569QQptdnZQQddnZQQadnZQQcmdZExpressItemQQtabnavZ6#tabs

Delco Remy Electrical Specifications & Selection Guide:
www.delcoremy.com/LiteratureDownload/documents/SpecGuide.pdf

1)   50VR on page 53
2)   50DN to 50VR Circuit system on page 129

FWIW

Sojourn for Christ, Jerry

[quantum500]

Thanks Jerry I was looking for that page last night and couldn't find it.  Good score on the ebay item too.  Thanks a bunch!

[junkman42]

Jerry, thanks on the headsup on the regulator, I ordered one to see if I could update mine.  I have as of yet not been able to find My regulator, I suspect it is behind the propane tank in the right rear cargo bay.  I am sure on a rainy night I will get to find it, LOL.  John

[quantum500]

Got the regulator.  Can I just put the battery, ignition and sense circuit on one wire?  Just make sure I use the the main battery cutoff switch so it doesn't drag the batteries down.

[Sojourner]

Got the regulator.  Can I just put the battery, ignition and sense circuit on one wire?  Just make sure I use the the main battery cutoff switch so it doesn't drag the batteries down.

Yes you can combine battery & ignition only if you used OEM bus's relay as shown Diagram A in your instruction sheet...otherwise jump or remove relay & separate ignition wire to panel shut down switch.
About the optional sense wire...this a great feature for buses because of extra long alternator's charge wiring to battery that will vary voltage under load between both ends (alternator's P terminal to Battery + post). The purpose for "sense wire" is to get the actual voltage right at battery's + post for optimum state of charge level. There is no load but only voltage in sense wire.
If you didn't get that instruction sheet with part....you can download the following link:

Delco Remy Electrical Specifications & Selection Guide:
www.delcoremy.com/LiteratureDownload/documents/SpecGuide.pdf

1)   50VR on page 53
2)   50DN to 50VR Circuit system on page 129 (same as instruction sheet)

FWIW

Sojourn for Christ, Jerry