Generator Over Charging Issue UPDATE

I cleaned the ground strap connection at the cross member. I also have a ground strap with the battery ground strap from the cross member to the transmission.

I also found that on the firewall terminal box the passenger side post was loose and could vibrate enough to contact the firewall. I tightened this up.

Using my analog meter I check edvoltage. At fast idle, I found 10 volts at the battery side of the cut out, 10 volts at the divers side terminal box post and about 8 volts on the passenger side post. Also around 8-9 volts at the light sockets.

Next I adjusted the third brush upwards to reduce the charging rate from 15 amps down to about 5 or so amps while at fast idle or open throttle.

I then found my voltage at the battery side of the cut out at about 6.5, about 8 at the drivers side post of the terminal box and around 6.5-7 at the passenger side post of the terminal box. Just a little better than 6 at the light sockets.

I installed a head light bulb, ran the throttle up and turned the lights on. The bulb burned fine. I left it on for a few minutes and it did not blow. I do not have voltage at the positive ground post to the frame.

Thoughts? Ideas? Is my system within tolerance? I have a spare generator ready to go. My armature post on the generator is a threaded style and a little loose in the case.
 
1930 coupe said:
The terminal box has a wire going from one post to the ammeter, and another wire from the ammeter back to the other post on the terminal box. The voltage on the two terminal box post should be the same using a analogue meter. Actually there will be a very small fraction of a volt difference but it is so small you cannot see it on a analogue meter and they will look the same.
You need to check your ammeter and the wires going to the ammeter. Terminals on ammeters get corroded and loose and will cause a voltage drop.
Click the link to download a .pdf wiring diagram.
Click to expand...

I thought about this. I am going to check the ammeter in the morning.

Mike, the battery is a fully charged optima 6 volt.
 
"I then found my voltage at the battery side of the cut out at about 6.5, about 8 at the drivers side post of the terminal box and around 6.5-7 at the passenger side post of the terminal box. Just a little better than 6 at the light sockets."

6.5 volts on the battery side of cutout with the engine at speed is a bit low. How could you get 8 volts at the terminal box?

It does sound like you have too much voltage drop through the cutout, and across the terminal box. It should be no more than .2 volts at either location with about 10 amps of current flowing. You could turn the lights on with the engine off and check the voltage drop across the terminal box again.
 
Tom Wesenberg said:
"I then found my voltage at the battery side of the cut out at about 6.5, about 8 at the drivers side post of the terminal box and around 6.5-7 at the passenger side post of the terminal box. Just a little better than 6 at the light sockets."

6.5 volts on the battery side of cutout with the engine at speed is a bit low. How could you get 8 volts at the terminal box?

It does sound like you have too much voltage drop through the cutout, and across the terminal box. It should be no more than .2 volts at either location with about 10 amps of current flowing. You could turn the lights on with the engine off and check the voltage drop across the terminal box again.
Click to expand...

Tom, I will try this also. I prefer my digital volt meter but I hear that an analog will perform better on a model A. approximately 8 volts going to the terminal box with about a 1 volt drop. I'm going to check out the ammeter too. It could be a problem. Congrats on the 17k plus posts. Someone should make you an award from used Model A parts, lol. I don't know what is beyond "senior member" but I say you have made "partner" in this firm.
 
I got to the bottom of my voltage problem. I had a short on the ammeter. The armor coated cable for the dash light at some point shorted out the ammeter. Probably at some point I had the dash out for some work and when I put it back together things got too close. I repaired this problem. I now have 6 volts everywhere I check.

My next question is how many amps is a good charging rate? Right now I have the generator set up just shy of 15 amps. What is a good rate of charge so I do not have discharge while the lights are on?

Second, I notice that the lights on the drivers side (headlights and taillights) are just a tad dimmer than the passenger side? Any ideas? Ground issues?
 
I wouldn't want more than a couple amps going into the battery. This means you'd set the third brush for 2 amps during the day with the lights off, then when you turn the lights on you move the third brush down so you increase the amps enough to carry the lights, plus one or two amps still going into the battery at fast idle.
 
If your going to treat your battery AND your generator right, you will need to adjust your third brush every time you want to use the lights, then back again when your not. THAT is why a voltage regulator is so nice, never have to do that again.
 
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