Alt putting out 25v...

Alt putting out 25v...

JR74CJ5

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Plumas Lake, CA, USA
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1974 CJ5 ~ Fresh built AMC 360 - SM420 - D20 - D30F with upgraded 30 spline shafts and knuckles & D44R - 4.27 Gears - ARB Lockers F/R - All chrome molly axles - on 33's - YJ 4" Lift Spring Conversion
So now that i have her back up and running, i decided to double check the alt was working. The amp gauge didnt look to be acting right to me. Ive had some issues with the alternator and wieing before...

Ill try to draw a diagram of what i have going on / how its hooked up tonight / tomorrow.

So after testing poormans way (jeep running disconnect bat, jeep died) figured it was not charging. So i test the back post on it with multimeter, 25 volts...???

Why am i getting 25 volts?

I dont know how to test the voltage regulator, but. It was replaced early this year...

Only other possible problem, i grounded the alt out against the fender one day (while replacing cam gear, didnt disconnect bat before starting... :banghead:)

Possible i fried the alternator? Should i have it tested?
 
Nice your running a 24 volt system on your jeep. Lol just kidding sounds like your voltage REG is not working right. Better get her checked out.
 
If your getting 25 volts your alternator is working. You might have fried your volt regulator when you grounded your alternator out on your fender. I fried 2 on my sand rail because of a grounding problem.
 
So now that i have her back up and running, i decided to double check the alt was working. The amp gauge didnt look to be acting right to me. Ive had some issues with the alternator and wieing before...

Ill try to draw a diagram of what i have going on / how its hooked up tonight / tomorrow.

So after testing poormans way (jeep running disconnect bat, jeep died) figured it was not charging. So i test the back post on it with multimeter, 25 volts...???

Why am i getting 25 volts?

I dont know how to test the voltage regulator, but. It was replaced early this year...

Only other possible problem, i grounded the alt out against the fender one day (while replacing cam gear, didnt disconnect bat before starting... :banghead:)

Possible i fried the alternator? Should i have it tested?

JR

:)I don't see how you could get 25 volts out of a 12 volt system? Do you have more than 1 battery? Most 12 volt alternators will only charge to 14-15 volts:confused: Check your muti-meter again..........or make it into a welder (LOL)
:D:D:D:D
 
I don't understand either :confused::confused::confused:

But only 1 battery.

So also...

  • At the battery I'm only getting 12. (not 13 / 14)
  • When i disconnect the battery jeep dies, so even though I'm getting 24 volts at the back of the alternator, (so technically its working) it's not getting to the battery anyway (charging).
This problem is stumping me a little...

:cool:

I've got some reading to do...
 
I will not claim any expertise at all but offer some things I believe to be true and ask a few questions.

with out a voltage regulator the alt is capable of making a lot more than 12 volts, from what I understand even 120V.

you say you have 12V across the battery and 24 volts from the alternator wire to ground? this is a bit hard to understand as it is basically the same circuit.:confused:

I say reading is a good idea but I think I would pull the alt and run to the vato zone to have it checked. just because it is quick and easy,:D
 
I don't understand either :confused::confused::confused:

But only 1 battery.

So also...

  • At the battery I'm only getting 12. (not 13 / 14)
  • When i disconnect the battery jeep dies, so even though I'm getting 24 volts at the back of the alternator, (so technically its working) it's not getting to the battery anyway (charging).
This problem is stumping me a little...

:cool:

I've got some reading to do...

:)JR: WOW 24 volts..........you'll have to enlighten me when you solve that one.
Obviously it is not sending anything to your battery since when you remove power the 12 volts to your Ignition goes away. Does that have a built in regulator? I would take it down to your local parts house and have them test the alternator and if the voltage regulator is separate an a easy off take it also.
:D:D:D:D
 
i think my wiring is messed up too, but it was all working fine before grounding out the alternator against the fender

thinking reg / alt needs replacement...
 
i think my wiring is messed up too, but it was all working fine before grounding out the alternator against the fender

thinking reg / alt needs replacement...

JR,

:)I do think you cooked it or pissed it off ...................:mad::mad::mad:
Anyway as IO suggested take a trip to your local parts house..........make sure you check all your charging wires and look for anything that has been cooked or discolored..........run an Ohm meter across them.
Take an aspirin and see how ya feel in the morning!
:D:D:D:D
 
You have to stop letting I0Port talk you into buying those fancy electrical tools. :laugh: Does the 74 have an external regulator? Im a little out of my element on the earlier ones.
i think my wiring is messed up too, but it was all working fine before grounding out the alternator against the fender

thinking reg / alt needs replacement...
 
You have to stop letting I0Port talk you into buying those fancy electrical tools. :laugh:

Maybe it's so fancy you have it set on X2.:D
 
Drop a chill pill and wash it down with something with alcohol in it.

this was my first question too but I suspect you have an internal regulator.

I still don't understand your voltage readings, please explain.

and why do I always get blamed for this electrical stuff, the man is old enough to own and operate a volt ohm meter. If he gets bit now and then it's just part of the learning process.;)


You have to stop letting I0Port talk you into buying those fancy electrical tools. :laugh: Does the 74 have an external regulator? Im a little out of my element on the earlier ones.
 
and why do I always get blamed for this electrical stuff.;)

Cause its fun. :D Or cause you make us dumb monkeys buy tools we wouldnt usually , therefore helping us in the long run. ;)
 
:laugh: Guys are cracking me up!

Yes it has a external regulator.

The voltage reading is blowing my mind though. I can read a multimeter :cool:


  • So if I measure the voltage at the battery terminals, i get 12.?? v running or off.
  • If I measure on the starter terminal, I get 12.?? v (matches battery reading)
  • If I measure the exciter wire, to the alt. I get 3.?? v (which is about right for it...
  • If I measure the :
attachment.php



A - Where the green wire from the voltage regulator goes to. (Field?)
B - Ground wire from the voltage regulator. Don't think there is an additional ground used. just the black wire from the voltage regulator
C - I get the 12.??v like the battery etc.
D - I get (when volt meter on 20v setting, it gives me a funny reading saying basically it's going over 20v. So I set to 200v (next setting up) and I get 24.?? v (This is the output terminal.)

The red drawn "glasses looking" things are 2 cylinder like objects that hook together and back to the posts. (They seem to hold some voltage in reserve or something, it's kinda weird...

So I haven't showed how I have everything hooked up yet, but will if alt checks out as good. However as said, it was working... Even though the wiring on my jeep is terrible! I will be thinking through a new wire harness build, and dash / gauge set up too. Simple and easy with a fuse block too :cool: but not yet... ;)

I know this all seems crazy, so I will double check this when I get home, but to my knowledge, this is what i was getting...

:chug:
~ JR
 
:laugh: Guys are cracking me up!

Yes it has a external regulator.

The voltage reading is blowing my mind though. I can read a multimeter :cool:


  • So if I measure the voltage at the battery terminals, i get 12.?? v running or off.
  • If I measure on the starter terminal, I get 12.?? v (matches battery reading)
  • If I measure the exciter wire, to the alt. I get 3.?? v (which is about right for it...
  • If I measure the :
attachment.php



A - Where the green wire from the voltage regulator goes to. (Field?)
B - Ground wire from the voltage regulator. Don't think there is an additional ground used. just the black wire from the voltage regulator
C - I get the 12.??v like the battery etc.
D - I get (when volt meter on 20v setting, it gives me a funny reading saying basically it's going over 20v. So I set to 200v (next setting up) and I get 24.?? v (This is the output terminal.)

The red drawn "glasses looking" things are 2 cylinder like objects that hook together and back to the posts. (They seem to hold some voltage in reserve or something, it's kinda weird...

So I haven't showed how I have everything hooked up yet, but will if alt checks out as good. However as said, it was working... Even though the wiring on my jeep is terrible! I will be thinking through a new wire harness build, and dash / gauge set up too. Simple and easy with a fuse block too :cool: but not yet... ;)

I know this all seems crazy, so I will double check this when I get home, but to my knowledge, this is what i was getting...

:chug:
~ JR

JR,

:)WOW..........Is there going to be a test on this subject?:confused::confused:

:D:D:D:D
 
Alright guys...

Here goes.

I don't know what if anything was wrong with the alternator. I took it to the down the street parks store, and they could not test it because they didn't have a code from year make and model. (it's a 55AMP output upgrade otherwise the exact same as stock... Guy PO'ed me... ) So I headed over to Pep Boys since where I bought this originally...

Got there and the poor kid they put on the testing machine had no idea what he was doing. After watching him fiddle with the machine for 20 min I finally stepped up and helped him out (as the other employees seems to just walk by and snicker). Finally we got it set up right, (he was trying to use a standard flat belt on my v groove pulley, among other issues..... Like I said, didn't belong on the machine) and it threw a code that said the adapter pigtail (machine part that adapts to different hook up types, basically their part not mine) was bad, order a new one. He tried using 3 different ones, and it kept saying the same thing. Finally a different guy walked by and I snagged him over. He said nope if it says doesnt work then it doesn't work... and walked away... I was a little upset... I asked the kid what we do now, suggesting without bashing him that we get help from a more knowledgeable person on staff. He got the same snide guy over to help again, and he says "what?" I say so what do we do now? he says well do you want to buy a new one now or go somewhere else? (Very rude...) so I look him in the eye and say "Tell you what, Why dont you :censored: give me a :censored: new one for free since your :censored: machine doesnt :censored: work and you want to be a :censored::censored::censored:" :D:D

Anyways, I'll shorten the story some, I spoke to the manager, and got a new one for free. :cool: I was insistent... :D

So not sure what if anything was wrong with the old alternator, as when I got home I was no longer getting 25 v, but was getting 15v and no additional volts were getting to the battery still.

So after some trouble shooting and wire tracing voltage regulator swap with my old (still good) one, I found the plug that had been fried along the alternator output wire. Replaced.

Walla, everything is working... Kinda... :rolleyes:

As of now... :cool:

:chug:
~ Jr
 
Glad you got it figured out.
 
Alright guys...

Here goes.

I don't know what if anything was wrong with the alternator. I took it to the down the street parks store, and they could not test it because they didn't have a code from year make and model. (it's a 55AMP output upgrade otherwise the exact same as stock... Guy PO'ed me... ) So I headed over to Pep Boys since where I bought this originally...

Got there and the poor kid they put on the testing machine had no idea what he was doing. After watching him fiddle with the machine for 20 min I finally stepped up and helped him out (as the other employees seems to just walk by and snicker). Finally we got it set up right, (he was trying to use a standard flat belt on my v groove pulley, among other issues..... Like I said, didn't belong on the machine) and it threw a code that said the adapter pigtail (machine part that adapts to different hook up types, basically their part not mine) was bad, order a new one. He tried using 3 different ones, and it kept saying the same thing. Finally a different guy walked by and I snagged him over. He said nope if it says doesnt work then it doesn't work... and walked away... I was a little upset... I asked the kid what we do now, suggesting without bashing him that we get help from a more knowledgeable person on staff. He got the same snide guy over to help again, and he says "what?" I say so what do we do now? he says well do you want to buy a new one now or go somewhere else? (Very rude...) so I look him in the eye and say "Tell you what, Why dont you :censored: give me a :censored: new one for free since your :censored: machine doesnt :censored: work and you want to be a :censored::censored::censored:" :D:D

Anyways, I'll shorten the story some, I spoke to the manager, and got a new one for free. :cool: I was insistent... :D

So not sure what if anything was wrong with the old alternator, as when I got home I was no longer getting 25 v, but was getting 15v and no additional volts were getting to the battery still.

So after some trouble shooting and wire tracing voltage regulator swap with my old (still good) one, I found the plug that had been fried along the alternator output wire. Replaced.

Walla, everything is working... Kinda... :rolleyes:

As of now... :cool:

:chug:
~ Jr

JR,
:)WoW! That might have been entertaining to have been there!
:D:D:D:D
:chug:
 

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