Farm Equipment - how to test charging system?

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how to test charging system?

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Category: Allis Chalmers
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=41442
Printed Date: 20 May 2025 at 1:54pm
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Topic: how to test charging system?

Posted By: skip(MO)
Subject: how to test charging system?
Date Posted: 01 Dec 2011 at 10:33pm

i know it's been asked and answered several times before, but there's usually about 5 different methods mentioned.

anyways, i have a d17 IV that isn't charging. i have no difference in voltage when running compared to when sitting (at the battery). how do i test to determine if it's a regulator issue or generator issue. or possibly just a loose, corroded wire.

and while we're talking about batteries, anyone know what to expect price wise for a good battery tray?

Replies:

Posted By: skipwelte
Date Posted: 01 Dec 2011 at 10:47pm

Run a ground wire from the field terminal on the genny to a ground. That will make the generator charge all it can. If the ammeter shows a charge then the regulator isnt working, if it doesnt show a charge the generator is most likley bad. Cannt help ya on a battery tray price. I had the regulator on my series IV diesel stick and burned up the generator, regulator, ammeter and wiring. That sucked cause the generator charged good. I had to run new wires from the genny to the regulator and back to the ammeter. I had a working generator, but had to buy a new regulator.

Posted By: Coke-in-MN
Date Posted: 01 Dec 2011 at 10:52pm

on a generator if you ground out the field terminal it will put full output to the A terminal

if you have a 10SI altenator look for the little U mouse hole in back , look inside and there will be a small tab sticking up from regulator , ground that to case and you will get full output .

This site should have all the info on generator

http://chevy.oldcarmanualproject.com/electrical/49dr324/index.htm - http://chevy.oldcarmanualproject.com/electrical/49dr324/index.htm

http://people.clemson.edu/~wsmth/ - http://people.clemson.edu/~wsmth/

http://www.atlma.us/index.php?topic=43.0 - http://www.atlma.us/index.php?topic=43.0 10SI

http://www.alternatorparts.com/cs130_sbpage2.htm - http://www.alternatorparts.com/cs130_sbpage2.htm

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Faith isn't a jump in the dark. It is a walk in the light. Faith is not guessing; it is knowing something.
"Challenges are what make life interesting; overcoming them is what makes life meaningful."

Posted By: DougS
Date Posted: 01 Dec 2011 at 10:53pm

Do what skip says. Check the voltage at the generator "bat" terminal too. If it reads 14 volts or more there, your wiring or ammeter may be bad.

Posted By: Brian Jasper co. Ia
Date Posted: 02 Dec 2011 at 7:41pm

Generators are easy to test. Do Skip's quick test. If it doesn't work, pull the belt from the gen, unhook the wires on it, and run a hot wire to the A term on the gen. It should spin like a motor. While motoring, ground the F erminal. It should slow down, but continue to motor. From there you can test the wires individually by using them to power a headlight bulb. Bright bulb = good wire. A bright light on the BATT term of the regulator will rule out a supply side problem. If everything passes, it can only be the regulator.

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"Any man who thinks he can be happy and prosperous by letting the government take care of him better take a closer look at the American Indian." Henry Ford

Posted By: briarpatch
Date Posted: 03 Dec 2011 at 5:58am

Last year I replaced both batteries on my 185 for $250 total.

Posted By: skip(MO)
Date Posted: 04 Dec 2011 at 10:21pm

i was changing the oil tonight in the car and tractor and remembered i needed to do this.....only problem is i was in the barn, internet isn't. the only response i remembered from here was grounding the "F" terminal. after doing that, i checked voltage from the other terminal (nothing), and checked the amp guage (nothing). i guess maybe i should print off some of what you sent me, coke. then i can have some good info and pictures for next time.....maybe do a little more in-depth checking.

btw, i was set on AC, not DC.....i'm assuming that's right for checking right off the genny???

Posted By: Brian Jasper co. Ia
Date Posted: 04 Dec 2011 at 10:34pm

No, you need to set the meter to DC.

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"Any man who thinks he can be happy and prosperous by letting the government take care of him better take a closer look at the American Indian." Henry Ford

Posted By: Chalmersbob
Date Posted: 04 Dec 2011 at 10:36pm

I remove the armature wire from the genny. connect a wire from the field terminal to ground and connect another wire to the armature terminal and to a loose amp meter and touch the 2nd terminal of the amp meter to the battery. If the genny is working the amp meter will show you. If it doesn't respond then look for your problem in the genny. If the amp meter does respond, then look at you VR or the amp meter in the dash, or wiring in between. Bob

Posted By: DougS
Date Posted: 04 Dec 2011 at 11:01pm

It will read DC when you are set on an AC scale. It just won't be as accurate. It will not read AC when you are on a DC scale. If you grounded the F terminal and there was no voltage on the A terminal, your generator is probably bad. One final thing you could do: Momentarily touch a live wire from your battery to the generator A terminal. This will re-magnetize the generator. Check the generator again per above after doing this.

Edit: Engine not running when you touch wire to A terminal, of course.

Posted By: Skyhighballoon(MO)
Date Posted: 04 Dec 2011 at 11:08pm

And don't touch the battery to the field terminal either Skip!

I got a good used battery tray for my Series IV at Cook Tractor in Clinton, MO...$25 I think back in 2006. A little bit of work to replace it with all the wiring going on underneath it. Mike

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1981 Gleaner F2 Corn Plus w 13' flex
1968 Gleaner EIII w 10' & 330
1969 180 gas
1965 D17 S-IV gas
1963 D17 S-III gas
1956 WD45 gas NF PS
1956 All-Crop 66 Big Bin
303 wire baler, 716H, 712H mowers

Posted By: skip(MO)
Date Posted: 05 Dec 2011 at 3:09am

i put a new amp gauge in last year, but the more i look around at the wires, i won't trust it's readings.....so i'll have to go by what the generator terminals tell me. it sounds like i verified the genny isn't working though, grounded the F term and read voltage on the A term......or lack of voltage.

so now i guess it's on to finding a replacement and changing the o-rings on the PD.....why the hell is it we think old tractors are so great?

Posted By: Brian Jasper co. Ia
Date Posted: 05 Dec 2011 at 6:40am

Open it up and check the brushes. I've found the brush holders stuck and not holding the brushes tight against the armature. Simply freeing them up is sometimes all thats needed.

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"Any man who thinks he can be happy and prosperous by letting the government take care of him better take a closer look at the American Indian." Henry Ford