Charging Question
Moderators: Cal_Gary, T. Highway, Monkey Man, robi
Charging Question
I noticed that after I drive around for a while (15-20 minutes), the battery gauge slowly creeps down out of the green onto the border line between green and yellow. Is this normal under operation? I hooked a charger up and both batteries were indicated at ~75%. I have the 100amp system.
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- SFC
- Posts: 557
- Joined: Tue Jul 07, 2015 10:44 pm
- Location: Fairbanks, Alaska and Nome, AK
Re: Charging Question
does the 100amp system have a solidstate regulator or the old coil and relay type? it sounds like either your regulator or generator is only producing power when it's cold. at least mine, stays 100% even during long drives.
Isaac
Fairbanks, AK
Civilian WM300 on DC3 tires
'52 M37 on 11x16 Michelin
'52 M37 on Apple R-1 tractor tires
Photo Gallery
Fairbanks, AK
Civilian WM300 on DC3 tires
'52 M37 on 11x16 Michelin
'52 M37 on Apple R-1 tractor tires
Photo Gallery
Re: Charging Question
I have the original 25amp generator, but changed out the regulator to a solid state one and went to the colored charging gauge instead of the original amp guage. My truck is at the top of the yellow with the ignition on but truck not running. When running it is always mid green.
I think you have a definite charging issue. I'm betting it is the voltage regulator
I think you have a definite charging issue. I'm betting it is the voltage regulator
Re: Charging Question
Another thing I noticed is that with the ignition on but engine not running, I can hear/see a spark occasionally jumping around in the alternator.
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- SFC
- Posts: 557
- Joined: Tue Jul 07, 2015 10:44 pm
- Location: Fairbanks, Alaska and Nome, AK
Re: Charging Question
i've never seen a plastic one, but i've never seen a 100amp system in person either. it's smaller than the big original ones so that's a good sign that it's a solid state system. it might be worth just checking the connections and making sure that there isn't a bit of corrosion going on, the solid state regulators don't usually go bad. at least not part way...it's usually all or nothing when they go
Isaac
Fairbanks, AK
Civilian WM300 on DC3 tires
'52 M37 on 11x16 Michelin
'52 M37 on Apple R-1 tractor tires
Photo Gallery
Fairbanks, AK
Civilian WM300 on DC3 tires
'52 M37 on 11x16 Michelin
'52 M37 on Apple R-1 tractor tires
Photo Gallery
Re: Charging Question
[quote]Another thing I noticed is that with the ignition on but engine not running, I can hear/see a spark occasionally jumping around in the alternator.
Sparks jumping across a Gen or Alternator is not a good thing. I wouldnt run the truck until you find out what going on...
Sal

Sparks jumping across a Gen or Alternator is not a good thing. I wouldnt run the truck until you find out what going on...
Sal

1954 M37 WO/W
1969 M101A1
1967 M416
1969 M101A1
1967 M416
Re: Charging Question
I have the 100 amp system in my 51. It has the same regulator as yours, which is a solid state. The 1/8" plug above and between the two harness plugs is an access port for charging adjustment. Spec calls for it to be adjusted to approx. 27.5 volts. Carefully turn the adjustment with a small screw driver after removing the plug. Measure it at the batteries with a volt meter, as you make adjustments. Since the 100 amp system uses an alternator, the fields are rotating, and use slip rings for the brushes. There should be virtually no internal sparking from normal charging operation. Mine is somewhat noisy when charging low batteries, but it gets less as the batteries top off.
MVPA Member #23780
1942 Chev. 1 1/2 Ton Dump Truck
1951 M37 W/W, & Field Radio
1958 Navy CJ3B
1967 M725 Ambulance
1987 M101A2 Trailer
1942 Chev. 1 1/2 Ton Dump Truck
1951 M37 W/W, & Field Radio
1958 Navy CJ3B
1967 M725 Ambulance
1987 M101A2 Trailer