The Stovebolt Site Forums The Shop Area The Electrical Bay Voltage regulator

I have a 47 3100 with original 6v system. The generator has been rebuilt. I have a NOS voltage regulator. I am having issues getting it to charge, or at least it doesn't appear to be charging. My amp meter points straight down to the 0. If I turn on the lights it drops to the left showing discharge. It doesn't matter how much I rev up the rpms. If I put some pressure on/bend the spring tab to increase spring tension in the regulator, it points to 0 at an idle but does swing over to between 20-30 AMPS charge when I rev up the RPMS. I say bend the arm. I bends it is so little I don't actuall feel or see it bend any, I am assuming it is and tighening the spring becuase it appears to charge. I drive the turck and after maybe 15-20 minutes I notice the AMP gauge is no longer moving again. I can tap on the spring arm again and get it to start charging. It is very sensitive. It I tighten to spring too much the AMP meter buries to the right when I rev the engine. It usually takes me 3-4 attemps to get the arm in just the right location. One thing that concerns me is am I damaging anything if I just tighten it up and not worry about it burying the Amp gauge past the 40 AMP mark

Sounds to me like you didn't polarize the generator.

You might try cleaning the contact points on the voltage regulator. I had the same thing happen - no charge until I cleaned the contact points. Use a business card or 1500 grit sandpaper if you have that. Do NOT use a file, as that's too aggressive. After cleaning my generator (which I rebuilt and tested) charged the battery. It does need to come off idle a bit before it shows a charge on the ammeter.

There's a specific procedure for adjusting the regulator, requiring both an ammeter and a voltmeter. It's outlined in the shop manual.

Check the voltage at the battery posts (NOT THE CABLE TERMINALS). A fully charged 6V battery will show around 6.3V with the engine stopped. With a properly operating regulator, the battery post voltage should be about 7.3-7.5 with the engine running at fast idle. Adjust the voltage regulator accordingly- - - - -BUT ONLY ADJUST IT WHEN THE BATTERY IS FULLY CHARGED!

IGNORE THE AMMETER- - - - -it's about as accurate as "measure with a micrometer- - - -mark with chalk- - - - -cut with an axe!" It's basically a charge/no charge indicator for dummies. It's normal for it to return to center once the battery gets refilled from running the starter. Once the starting load is replenished, the ammeter will return to near center, and the generator will supply the running current for ignition, lights, and other electrical demand. A big deflection toward the "charge" direction after starting and a gradual tapering back toward center is NORMAL operation.

Insisting on seeing a constant "charge" indication on the ammeter will boil the battery dry and destroy it in a short time. There's a good reason manufacturers stopped putting ammeters on vehicles- - - - -"Idiot Light" is a very good descriptive term for a "no charge" indicator. That light is smarter than all drivers- - - - -and most mechanics!
Jerry

x2 on Jerry's mention of the constant charge ammeter reading. Also if you happen to have bought one of Wal-Mart's most inexpensive batteries, please be aware of a couple of things: 1...they are okay as today's auto batteries go (not nearly as good as in the past but fine for the cost) and 2...very important...you may have a battery that just like its elder relatives needed the water level checked regularly. And this may have become sort of an unexpected maintenance routine as most auto batteries don't require it any longer. Fill it as you always did (up almost to the little split part of the internal fill well thing) and use distilled water if you have it.

I have an Optima battery. I still need to run the voltage test recommended.