Farmall Super C charging too much

   / Farmall Super C charging too much #1  

sixdogs

Super Star Member
Joined
Dec 8, 2007
Messages
13,601
Location
Ohio
Tractor
Kubota M7040, Kubota MX5100, Deere 790 TLB, Farmall Super C
I have a typical Super C tractor that just goes on long tractor drives with the guys. The amp gauge would normally show maybe 5-10 amp on a ride. It has a crappy battery and had a new voltage regulator on it when I bought it. I had a shop check the generator last year and they said it was OK.

On the final drive this fall, the amp reading suddenly shot to the max at 20 amps on a high speed drive, stayed there and would cut out and go to a discharge at times. When I got home I noticed the battery had been boiling, likely from high charge and there was some electrolyte pooled on the top of the battery. I put the tractor in the back barn for winter, took the battery out and now it's time to fix. I think the battery might have a dead cell.

I rebuilt simple generators like this (6V NG) decades ago but forgot it all. I fiddled with regulators too but generally just replaced them. Also forgot all that.

Now what and where should I look first?
 
   / Farmall Super C charging too much #2  
A shorted cell in the battery will draw huge amps and boil a battery. Perhaps your charging system is fine?
 
   / Farmall Super C charging too much
  • Thread Starter
#3  
A shorted cell in the battery will draw huge amps and boil a battery. Perhaps your charging system is fine?
If the battery was dead, would , or could the amp gauge show a discharge at times when hot? And then when I start it up again, it shows charge until it gets hot?

I only drove it a little for that observation so it may not happen every time.
 
   / Farmall Super C charging too much
  • Thread Starter
#4  
A shorted cell in the battery will draw huge amps and boil a battery. Perhaps your charging system is fine?
I knew the battery was bad so had it checked and it was dead as a doornail. I planned to replace anyway so picked one up and will install soon and let you know how it turned out. It would be nice if it was a bad battery. Last fall it would barely take a charge and almost failed to start the tractor in hot weather despite having a charger on it all day.
 
   / Farmall Super C charging too much #5  
just check the voltage, a dead cell will cause a short, and create heat which will increase amperage. Most likely the battery
 
   / Farmall Super C charging too much
  • Thread Starter
#6  
So I replaced the battery that I knew was bad and here's what's going on now. I put a one amp charger on it overnight.

At low idle, it's a slow discharge. At fast mid-RPM it about 15 amps. At a 80% RPM's it about 20 amps and at wide open the gauge goes over the max of 20 amps.
 
   / Farmall Super C charging too much #7  
put an amp meter on it, to confirm the gauge is working properly, something like this Amazon.com
 
   / Farmall Super C charging too much
  • Thread Starter
#8  
   / Farmall Super C charging too much
  • Thread Starter
#9  
Neighbor came over and at very low idle the tractor amp gauge showed a slight discharge and his meter showed 6.8 volts. At halfway on the throttle my tractor showed 10 amps while his meter showed 9.2 volts.

At full rpm, my amp gauge was off the 20 amp mark to maybe 25 amps while his meter showed 11.2 to nearly 12 volts. When we went to double check the tractor a minute later the tractor was at zero but his meter showed 11.20.

It sounds like a bad gauge but I those charging amounts seem awfully high.
 
   / Farmall Super C charging too much #10  
your saying volts, do you mean amps?
 

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