The Stovebolt Site Forums The Shop Area The Electrical Bay 6v system not charging. Troubleshooting list?

I'm just looking for an "order of operations" list here. I'm pretty handy with a multimeter and know enough not to lick any bare wires.
Got the old beast running again yesterday after restoring the fuel system. Drove it around the parking lot a bit and decided to see if my charge gague was telling the truth.

Pulled the battery cable and it died right away.

In an effort to search for horses instead of zebras, I put it to you, fellow bolters, what are the first things I should look for/replace/smack with a hammer?

-J

It's good to take a lap around the lot even though I know it's running on batteries. (does this make it a hybrid? *grin* THINK of what you could do with regenerative brakes on a 6600lb panel truck!!!! I'd be off the grid in NO time!)

How fast wuz the engine running when you pulled the cable? Generators don't charge at idle like alternators do. Your system may be working normally.

Well... You're right. I had it at a really fast idle. I'll try it again while I'm giving it some gas. Judging from the amount of dead-end wires and frayed cloth insulation and extra (?) wiring everywhere, I don't have very high hopes though. What I DO have is a fire extinguisher.

I'll report back with results.

Leave your bat. cables on & get out that V.O.M. your are refering to. It should read about 12 volts before you start it. Start it up & accelerate the engine. The voltage should run up to about 7 volts. If it doesn,t & I assume it,s a GM & not a Ford, Remove the wire from the f term. on the regulator & ground the wire. Than acelerate the engine & see if the voltage goes up. If it doesn,t the generator is bad. If it does the regulator is bad. This is assuming the wireing is working.

Ummm say that again?

If the voltage goes up... the generator is bad.
If the voltage DOESN'T go up... the generator is bad.

Should I just throw it away now? *grin*
I assume the terminals you speak of are in the voltage regulator on the firewall?

Thanks again for your advice. I hope to check this out tomorrow.

-J

read "More good tips and information from [censored]:"

Bill

I had the same problem with my '46.

Grandpa and I pulled the generator and we cleaned up the brushes and armature and popped it back in.

Works like a champ now.

Item #1: Read the article I wrote about generators/regulators in the Tech Tips section.

2. DO NOT remove battery cables with the engine running! it causes big voltage spikes that damage things. (Especially solid-state voltage regulators in self-contained alternators!) It's not good for mechanical regulators on generator/regulator systems, just not as deadly. I've seen spikes of over 100 volts from a 12 volt alternator.

To polarize the generator, remove the wire from the "Arm" terminal at the regulator, and touch it to the "Bat" terminal for half a second or so. You'll get a medium-sized spark. If you get a BIG flash, the armature is shorted, and it's time for a new generator. Reconnect everything, and start up. The voltage should rise to about 7 volts at the battery terminals at a fast idle if everything is working OK. If not, take the "Fld" wire off the regulator and ground it to the regulator base. Check the voltage with it grounded. Voltage should be above 7 volts, and should rise further if you rev up the engine. If the generator is charging that way, it's time to adjust or replace the regulator.
Jerry

Sorry I didn,t explain it good. If the voltage goes up with the field grounded the generator is good. If not it is probably the regulator.

Couldn't you just clip the meter leads to the terminals on the generator with the engine running to test for a working generator?

The voltage at the armature terminal of a 6V generator can be anywhere from 1/2 volt to 7.5 volts, and still be within normal performance range. A properly polarized generator, with no wires connected to it will produce about 1/2 volt due to "residual magnetism". Once current begins to flow through the field windings the voltage will rise to about 6.5 volts before the cutout relay points close. Depending on the state of charge of the battery, correct generator output can vary from 6.5 volts to 7.5 volts, and still be within normal range. Unless both voltage and current flow are monitored, any measurement will be an educated guess. The state of charge of the battery has more influence on what the generator does than the regulator. The function of a regulator is simply to prevent overloading of the generator, or overcharging of the battery.
Jerry