Current draw with vehicle off

[TIGERFANS2]

Has anyone checked to see what the current draw (swich off) is in their deuce?

 

[Blood_of_Tyrants]

It should be zero.

 

[roger-wilco-66]

Yeah, as BfT said, should be zero, but not on mine. Something is drawing a small amount of energy, haven't found out yet what it is. It draws enough that when I connect the battery I see small sparks. The batteries last a few days that way, but I have to unhook them when it sits longer (do that anyway as a security precaution).

Mark

 

[TIGERFANS2]

I asked because I checked mine last night and though it's low (~800ua) it's not zero. I'd like a schematic of the voltage regulator to see if < 1 millamp is kosher.

 

[dittle]

If your truck has a heater in it the blower switch may be wired on the wrong side of the dash power switch. I got told by some AMSA guys that when in a hurry a lot of the blowers got hooked up incorrectly. I'm going to guess that if you switch is a little weak it could let some current through. Thats why I put battery disconnects on my truck (as well as trying to prevent someone from stealing it w/out some effort)

 

[Stalwart]

One or more blown diodes in the alternator will cause this. Follow the instructions in your TM's for the testing proceedure.

 

[Scrounger]

As already posted there should be zero current draw when the master switch is off. If there is a slight draw more likely than not one of the diodes in the regulator is going bad. The alternator will still charge with a bad diode; however it won’t be long before the regulator will have to be replaced. Another place for a draw is if the exciter wire going from the master switch to the alternator is connected to the hot side of the switch instead of the switched side. If it is then there would be a constant draw and shortened life of the alternator.
A quick test to see if it is the alternator is to connect a meter at the battery and disconnect the alternator. If the draw goes away it is a faulty diode.

 

[Tackettr]

Both of my M35s create a small arc when you attached the dog bone. I was told when I searched it on here sometime ago that it was something in the generator (diode or something) and normal. My trucks have new 6tls in them and have set up to a month so far with no problems starting. We'll see how they do this winter.

 

[Tackettr]

Well I guess it may not be "Normal" but I can't seem to find any troubleshooting related to bad diodes in the regulator. Any help???

 

[Stalwart]

I found it proceedure in a Gama Goat manual, it's a std. M-series alternator, manual went away with the Goat. It will be the same proceedure for nearly any M-series truck.

 

[gringeltaube]

TM9-2920-225-34 covers all models of alternator/generators.
Lots of info, including how to check (internal) regulators.

 

[Trailboss]

I've noticed a spark on only one of my Deuces when I hook up the battery cables. That one came with fairly fresh but very dead batteries from GL. I put a battery post switch on the negative post of the first battery and keep it off unless running.

I've been working on the other problems on that truck (leaking injector pump and air compressor stopped working) and thought I had a short somewhere I needed to trace out.

Thanks for the generator/alternator hints.

 

[Keith_J]

The diodes in the alternator are not perfect "check valves" for rectifing the AC from the alternator. They each much handle millions of current reversals over the life the the alternator. So why an alternator? Better regulation and much better output at low RPM.

There are 6 of these huge diodes in the alternator. This means 6 times the chance of a component failure so check them. Not every 63B in the Army knew how to use STE-ICE gear. And even fewer wanted to check it out of the tool room during every charging system malfunction, preferring to just check output voltage. But a voltmeter won't find a single bad diode.