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willysmjeeps.com :: View topic - Power Issues 24V
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Power Issues 24V

 
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bikemancs
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Joined: Sep 05, 2011
Posts: 49
Location: Fayettenam, NC

PostPosted: Tue Mar 13, 2012 6:49 pm    Post subject: Power Issues 24V Reply with quote

OK guys, I need some help...

A few weeks ago diagnosed my Jeep with a bad generator. Batteries were not receiving a charge and were sitting at about 9.5V give or take. Bought a NOS/rebuild from Ron and installed it this past Sat. Used the Dodge to get her up to par and than ran her for about 30 or so minutes doing runs up and down a back street. Started her up again on Monday, started right up, no issues. Today, I knew she was low on gas so I was going to run her down to the gas station, well, looked in the tank and parts were dry so ended up running down with a gas can, dropping 2 gallons in. She started a bit rough but caught eventually. Ran her down the road, maybe 5-7 minutes, most at a wide open throttle. Took about 10 minutes to fill up.

Went to start and NADA. made it sound like the batteries were D.E.A.D. A buddy happened to be pulling in and we hooked up the jumper cables. attached to the under hood battery... no real change. hooked up to the cowl battery and after about 10 minutes, she got going again. Got her back to the VFW post and borrowed a voltmeter. While running tested both batteries. Voltage on each was 11.5-11.8V. The entire system, at idle, was 23.5/23.6V. When revved, the same.

I parked her for the night as to not get pissed off and do something stupid.

So...

What do I need to check, and where do I need to check? I don't understand the reliability issue. It used to be just fine. even with the low batteries it would start, eventually.

We will be working on it Friday since I am going to drive it in on Sat for our Buddy Poppy drive... Would really like to not have to jump it every time I want to drive it.
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OKCM38CDN
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Joined: Feb 17, 2012
Posts: 423
Location: Del City, OK

PostPosted: Tue Mar 13, 2012 7:50 pm    Post subject: Reply with quote

Possible bad regulator... search for threads o troubeshooting Generator / Regulator...

Is it solid State or What they call Bread box (Original Regulator)

Hope this helps...
_________________
Hal, KB1ZQ
TSGT, USAF (Ret)
1952 M-38 CDN CAR 52-31313
1952 M-100 Strick #104
1951 Willys Wagon (For Sale)
1954 Willys M38A1 (Restoration In Progress)
Tornado Alley
Del City, OK
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bikemancs
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Joined: Sep 05, 2011
Posts: 49
Location: Fayettenam, NC

PostPosted: Tue Mar 13, 2012 7:56 pm    Post subject: Reply with quote

Breadbox/Auto-Lite external regulator.

I just don't want to go open stuff and end up messing something else up worse than it is.
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wesk
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Joined: Apr 04, 2005
Posts: 15106
Location: Wisconsin

PostPosted: Wed Mar 14, 2012 1:12 am    Post subject: Reply with quote

A good rule to follow with electrics is "If you don't understand it then don't F--- with it!"

I don't mean this in a mean way.

Mistakes handling 24 V systems can result very quickly in a lot of smoke and a lot of money. I have cautioned folks for years to always disconnect the battery ground before taking the cover off a voltage regulator. Guess what? Once a year I get a comeback a week later looking for a new firewall harness. I also hear a lot of pain coming from the finger rings and wrist watches leaving scarring burns when they come in contact with the 24 V's.

Buying one part at a time in the name of trouble shooting is the most expensive way to troubleshoot a basic DC generator system.

Unless you have a copy of TM 9-1825B 1952 edition then don't even pull the cover off the regulator.

Just hit the basics with a few basic tools like a digital volt meter for less than $25 is a must have. The M series electrical connector test set is another must have. As are a few test/jumper leads.

Go to our "Downloads" page and download the portions of TM 9-1825B that you need plus any wiring diagrams you may need.
http://www.willysmjeeps.com/v2/modules.php?name=Downloads

1- Charge batteries and load check them. If you don't know how to do this then remove them and take them to Sears or your local battery dealer and have them load checked. Batteries with weak or shorted cells will not be of any help to you trying to troubleshoot an electrical charging issue.

2- Any generator that has not been in service needs to be polarized before you try to use it. If you don't yet have a test lead adapter set then remove the fat cable from the generator and flash the field. What does "flash the field" mean? It means momentarily applying a full 24 volts to the generator's field. How do you do that? You attach a jumper lead from the battery terminal on the starter then just touch it to the "B" pin of the generator's connector on top. Remember the other end of that lead is now hot! So disconnect it before you lay it on the metal. Now connect the fat cable and start the jeep. Ground the black lead of your digital volt meter to the chassis and clip the red lead to the same battery post on the starter and leave it there. If it reads between 27 and 28.5 volts at a fast idle you win. If it is less than that go to step 3.

3- Full field your generator. How? Well shut her down. Disconnect the fat cable again at the generator. Loosen the generator belt so you can spin the pulley by hand freely. This time you attach the volt meter's black wire to ground and the read wire to pin "C" of the connector on top of the generator. Connect the jumper lead to that same starter terminal again. Remember the other end of that lead is now hot! Now start the jeep. Now touch the free end of the jumper lead to the "B" terminal pin in the connector on top of the generator and look at the meter. It should climb immediately to 28 or more volts. Don't let it get above 32 volts. As soon as it hits 28 volts remove the jumper lead from the "B" pin. This means the generator is good. Hook the fat cable back up. If you did not get over 26 volts go to step 4.

4- This is where you disconnect the battery ground cable and remove the cover from the voltage regulator. Before you do this be sure you have read thru TM 9-1825B at least twice on how to clean contact points and adjust relays. If you are not confident at this point then remove the regulator and take it with the generator to your local auto-electric shop.


Plug on top of the generator


This is also the setup for polarizing the generator.


The layout of your Auto-Lite regulator.

The CB or circuit breaker disconnects the regulator from the generator when the generator is not turning (engine off). If this unit sticks open then the generator's output does not get any further then here. If it sticks closed the battery is connected to the non-turning generator and will then turn it just like an electric motor. If the belts are really tight then it will just fry the generator and you are out $300 bucks. This kinda makes a battery disconnect a real treasure to have close by and handy!

The CR or current regulator limits the current to 25 amps or so.

The VR or voltage regulator regulates the voltage between 26 and 28.5.

If you don't fully understand what is going on here at this point get help.
_________________
Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100

Mjeeps photo album: http://www.willysmjeeps.com/v2/modules.php?set_albumName=Wes-Knettle&op=modload&name=gallery&file=index&include=view_album.php
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bikemancs
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Joined: Sep 05, 2011
Posts: 49
Location: Fayettenam, NC

PostPosted: Wed Mar 14, 2012 6:16 am    Post subject: Reply with quote

Thanks Wes, now I know what I'll be reading in my off time for the next few days.
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bikemancs
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Joined: Sep 05, 2011
Posts: 49
Location: Fayettenam, NC

PostPosted: Fri Mar 16, 2012 6:15 am    Post subject: Reply with quote

Ok, so I read over most of this and using wes' diagrams, this is the plan of attack:

1. Get batteries checked and verified of "wellness" for voltage and load.
2. Presuming batteries are good, Polarize the generator.
3. Cross fingers #2 works
4. If still not correct, Full Field the generator.
5. If this doesn't work, find someone a lot more familiar than the group that will be working on it and ask/get help.

Any other ideas to be checked before #2? Grounding strap was brought up from someone more familiar with 60s era civi jeeps.
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wesk
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Posts: 15106
Location: Wisconsin

PostPosted: Fri Mar 16, 2012 9:50 am    Post subject: Reply with quote

In every electrical problem clean, tight connections is a absolute necessity and usually goes without saying but is often left out of discussiions by us old timers simply because it's a basic premise and we often assume too much.

The troubleshooting charts in the M38 and M38A1 manuals always include clean, tight connections or tight fuel fittings and etc.

The gound strap referred to is between the frame and the right front engine mount.

Quote:
4. If still not correct, Full Field the generator.

This step will only pin down wether the generator is good or not.
_________________
Wes K
45 MB, 51 M38, 54 M37, 66 M101A1, 60 CJ5, 76 DJ5D, 47Bantam T3-C & 5? M100

Mjeeps photo album: http://www.willysmjeeps.com/v2/modules.php?set_albumName=Wes-Knettle&op=modload&name=gallery&file=index&include=view_album.php
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bikemancs
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Joined: Sep 05, 2011
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Location: Fayettenam, NC

PostPosted: Fri Mar 16, 2012 11:32 am    Post subject: Reply with quote

OK, sounds good, thanks.
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bikemancs
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Joined: Sep 05, 2011
Posts: 49
Location: Fayettenam, NC

PostPosted: Fri Mar 16, 2012 8:23 pm    Post subject: Reply with quote

Ok, Polarization didn't do anything, attempting one other change and if that doesn't work will be shipping the whole setup to Ron for testing.
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