The Stovebolt Site Forums The Shop Area The Electrical Bay Discharge ---- Charge

First real ride out in the 46 Stylemaster today. It was an experience to say the least but it was so much fun. A lot more different than a new corvette, even surprisingly different than the 70's muscle cars I am used to rolling around in.

Anyway, onto the so called problem of the day. I was driving with the lights off, and the system was "charging." Gauge showed needle all the way over at charge when the car was under load... however as so as I turned on my amazingly useless lights, the gauge immediately went to discharge and did not recover until I shut the lights. Is this correct. I know in a new car this would indicate a alternator replacement or in this case I am thinking generator; or is this normal?

DG

the first indication of a problem is the "all the way over at charge" .... you've got wiring problems or a bad regulator [maybe stuck], the ammeter should show a slight charge just after starting while the generator is replacing the current taken by the starter, but it should quickly go to neutral [center], and when you turn on the lights, it should flick toward discharge for a second until the regulator makes the generator take up the slack

Bill

Bill,

How can I un-stuck my voltage regulator, as I believe this maybe the issue?

DG

well, just take off yer shoe and give the reg a sharp smack with the heel really - the back-in-the-day side of the road fix, but you should also take off the cover and see if there's obviously burnt points in there

Bill

Run somethig like a business card between the points might clean them. Dont use files or sandpaper.

Did you start out with a fully-charged battery? 6 volt systems don't recover from starting loads nearly as quickly as 12V systems do, even generator-equipped ones. That system should have a 25 amp capacity generator, which will support the headlight load and ignition with a very little bit of amperage left over to charge the battery. A fully-charged battery is essential to proper operation of a 6 volt electrical system, particularly if it's not a daily driver!
Jerry

I agree. I wouldn't look any farther than the battery.

Thanks for the advice guys. I put 100 miles on the car today without a single electrical problem. All the while the needle was dead smack in the center. On my way home I tossed on the lights, again needle went all the way down to dischage and stayed there. But the lights were bright (well for a 6V at least). That voltage regulator is definitely the issue. I will have to take a closer look at the tomorrow. The battery is Brand New from Napa, has 100 miles on it .

Thanks for the tips,

Dan

The gauge on my '54 GMC sometimes sticks in the full charge position after a surge like that. Tapping on the glass sends it to it's proper place.

Before you condemn the regulator, at least open it up and inspect things. The set of points behind the Bat. terminal are the "cutout relay". They're supposed to be open with the engine off, and should close as soon as the generator develops enough speed to get its voltage higher than the terminal voltage at the battery. They usually close as the voltage at the armature terminal gets to 6.5-7 volts. Closing voltage is adjusted by changing the tension on the spring that holds the points open. More spring tension- - - -higher closing voltage. Once closed, they don't reopen until the generator drops below battery voltage again. This prevents the battery from discharging itself theough the generator. Once it's charging, the generator output is controlled by inserting or removing resistance between the field terminal and ground. A grounded field produces max generator output. The center set of points controls maximum current, usually set to control at 25 amps. At current flows below that amount, the points behind the F terminal control voltage, usually at a maximum of 7.5 volts.

The current regulator OR the voltage regulator will take control, not both at the same time. These sets of points are in series with each other. High current control will happen at a voltage well below the voltage regulator setting, and the voltage points will not begin to take control until the current flow drops beloew the amp limit. Dirty points at either voltage or current position will stop the charge from happening. The current and voltage limits are set by slightly adjusting the spring tension on the points. A small change in spring tension can make a BIG difference in the setting. Use a piece of clean business card or index card to clean regulator points, NEVER a file or sandpaper. The points contact with a slight wiping action to try to self-clean, so the scratches left by even very fine sandpaper will cause them to stick. Stuck regulator points cause current or voltage to increase well beyond their proper settings. NEVER close a cutout relay by hand- - - -you can create a dead short through the generator armature which will burn out the generator, regulator, or both!
Jerry

Here are some steps to take.
1. Check battery water and general battery condition to
see if it will take and hold a charge....Load testing
may be necessary.
2. Check wiring for damage and make sure all
connections at generator, regulator and battery are
tight and free of corrosion.
3. Make sure fan belt is tight enough to drive
generator at full capacity.
4. Run engine at medium speed. Using a wire, touch one
end to regulator base and other end to a good ground.
If this corrects trouble, regulator is not properly
grounded anymore.
5. If test 4 does not correct trouble, make this test.
Connect a wire from regulator terminal marked "ARM" or
"GEN" to regulator terminal marked "BAT" with engine
running at medium speed. If charging rate increases,
replace old regulator.
6. If test 5 does not correct trouble, make this test.
Connect a wire from "FLD" Terminal of regulator to a
good ground with engine running at medium speed. If
Charging rate increases, replace old regulator.

If none of the above test show a bad regulator then
there is probably a problem in the generator itself.

Ken