AMMETER FLUTTERS

DIVCOMEL · 2 Weeks Ago

The indicator on my ammeter in my '49 DIVCO truck flutters whenever the engine is running. If my battery is in a discharged state, the indicator will move towards the negative side of the meter and flutter there until the system recharges the battery which usually takes about 10 minutes. Then the indicator returns to the mid-position and continues to flutter. The indicator never goes positive even when I rev the engine. Does anyone know of a cure for this condition? My truck was converted from 6 to 12 volts at some time before I bought the truck and the generator was replaced by an alternator. Is it possible that my gauge is for a 6 volt system? Since I bought the truck, I have replaced both the alternator and voltage regulator. Other than this gauge problem, the charging system seems to work fine. Thanks for any ideas or help on my gauge problem.

msmazcol · 2 Weeks Ago

Hello to a fellow Divco owner. Your Amp meter problem could very likely be related to your 12 volt conversion. All too often people mean well while "updating" but can create a monster. Unless someone had the gauges re-worked that would be a good clue to your problem. How about installing an external amp meter even if just as a test and then see how your charging holds up. If you are not killing the battery or boiling it over chances are you are fine.
I would also be concerned if your amp gauge has not been updated that you could have a melt down situation. Some vehicles have amp gauges that interrupt large gauge wire. These systems are not always fused as carefully as you might hope. Be careful not to have things get ugly. I would certainly look deeper into the conversion.
Consider a GOOD battery shut down switch in a spot you can READILY get to. I served 11 years on the local FD. Most car fires were due to electrical melt down. That is if they were not planned for profit ahead of time!

47jag · 2 Weeks Ago

Divcomel,

The ammmeter doesn't care if it's 6 or 12 volts. 6 volt systems actually use twice as much current for a given task. The wiring is thicker to reflect this. Has the flicker always been there (even with the previous alternator)? Check the ammeter connections. The suggestion of using an external ammeter is a good one. Connect it in series with the original. They should read the same amount and if both flicker the problem is elsewhere. The flicker could be due to a blown diode in your alternator. This usually reduces the max. output to about 10 amps. Get a load test done on the alternator.

Art

51dodge panel · 2 Weeks Ago

Make sure reg is grded good, make sure u have a grd strap from eng to firewall, this will bring everything together, completing your charging system. There are alot of cheap external reg on the mkt today, (kind of sounds like that is the problem, points won't stay closed so you get the flutter, good luck.

DIVCOMEL · 2 Weeks Ago

Quote:

Originally Posted by msmazcol

Hello to a fellow Divco owner. Your Amp meter problem could very likely be related to your 12 volt conversion. All too often people mean well while "updating" but can create a monster. Unless someone had the gauges re-worked that would be a good clue to your problem. How about installing an external amp meter even if just as a test and then see how your charging holds up. If you are not killing the battery or boiling it over chances are you are fine.
I would also be concerned if your amp gauge has not been updated that you could have a melt down situation. Some vehicles have amp gauges that interrupt large gauge wire. These systems are not always fused as carefully as you might hope. Be careful not to have things get ugly. I would certainly look deeper into the conversion.
Consider a GOOD battery shut down switch in a spot you can READILY get to. I served 11 years on the local FD. Most car fires were due to electrical melt down. That is if they were not planned for profit ahead of time!

Thanks for the warning. I had a battery cutoff switch in my inventory of parts that I never installed. I did that today!

DIVCOMEL · 2 Weeks Ago

Quote:

Originally Posted by 47jag

Divcomel,

The ammmeter doesn't care if it's 6 or 12 volts. 6 volt systems actually use twice as much current for a given task. The wiring is thicker to reflect this. Has the flicker always been there (even with the previous alternator)? Check the ammeter connections. The suggestion of using an external ammeter is a good one. Connect it in series with the original. They should read the same amount and if both flicker the problem is elsewhere. The flicker could be due to a blown diode in your alternator. This usually reduces the max. output to about 10 amps. Get a load test done on the alternator.

Art

Thanks for your suggestions. I don't know about previous operation because the truck was a basket case when I bought it. It had been sitting in a field since '84. The wiring was so bad, I had to completely rewire the truck. Before I tried to start it for the first time, I took the alternator and voltage regulator off and had them checked at our local auto electric shop. They told me they were both bad and sold me new ones. So, since I got the truck running, it has always had the flicker in the gauge. Getting a load test on the alternator is a good idea. Thanks.

DIVCOMEL · 2 Weeks Ago

Quote:

Originally Posted by 51dodge panel

Make sure reg is grded good, make sure u have a grd strap from eng to firewall, this will bring everything together, completing your charging system. There are alot of cheap external reg on the mkt today, (kind of sounds like that is the problem, points won't stay closed so you get the flutter, good luck.

Thanks for your help. I do not presently have a ground strap from the engine to the firewall. I will try that.

ply33 · 2 Weeks Ago

Needle moves to left (discharge) when the battery is discharged until it is charged when the needle is in the center?

Was this vehicle originally designed for 6v positive ground? If so then the the ammeter will read backwards when you set it up for 12v negative ground. Cure for that is to reverse the wires on the back of the ammeter.

Seems like all modern gauges have damping built into them so the needles move relatively slowly and don't bounce around too much. I know on my old car there is no damping on the electrical gauges: You can see all the sloshing of gas in the tank. And you can see the ammeter moving slightly when at idle if you have a slight miss, just enough to make the RPMs change a little.

I don't know how much your needle is "fluttering" but if its not too much it might just be a normal thing.

rsb · 2 Weeks Ago

Check if your fan belt is tight.

sfair · 1 Week Ago

Is the 12v conversion a GM (Delco) alternator with an external regulator? Does the top come off of the regulator? If yes, how many relays or poles?