View Poll Results: voltage reading

0.0 to 1.0

50.00%

1.1 to 5.0

16.67%

5.1 to 10.0

10.1 to 15.0

15.1 to 20.0

20.1 to 25.0

25.1 to 30.0

30.1 to 35.0

33.33%

Voters: 6. You may not vote on this poll

will you help with this easy test

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Dec 15, 2010 | 07:19 PM

havns3

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Joined: Sep 2006

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From: northeast missouri

will you help with this easy test

ncpartsman and i have been trying to solve a little altenator problem in a diffrent thread. so i thought we all could do a little easy test then report your results here in a poll.
the test is simple, just grab your DVOM set it to 200 AC Voltage. then touch the probes red to positve, black to negative. report your reading here. easy pleasy lemon squeezey.

thanks

Dec 15, 2010 | 07:23 PM

Maxium4x4

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From: Ohio

Mine was zero, no AC volts

Dec 15, 2010 | 07:27 PM

cheezit

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From: N. Fort Worth, tx

.3v ac the last one I checked.
I think tim needs to spend $10 at radioshack for an auto ranging meter

Dec 15, 2010 | 07:30 PM

bismic

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after the glow plugs kick off and the alternator kicks in?

Dec 15, 2010 | 07:32 PM

cheezit

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From: N. Fort Worth, tx

yup thanks for pointing that out. you should not reall yhave any a/c voltage till after its running. IMO it dc batteries dont do a good job storing ac voltage.

Dec 15, 2010 | 08:07 PM

havns3

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Joined: Sep 2006

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From: northeast missouri

this is why i am doing this i replaced my other altennator with a new replacement under oreilly's lifetime warrenty. and i am still getting high ac readings so i am wondering if its the alt. or how i am testing it

Dec 15, 2010 | 08:08 PM

havns3

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Joined: Sep 2006

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From: northeast missouri

Quote:

Originally Posted by bismic

after the glow plugs kick off and the alternator kicks in?

yes thanks for clarifying that i should have said that

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Dec 16, 2010 | 06:56 AM

bismic

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I am very interested in this as well. I will check tonight.

Dec 16, 2010 | 07:02 AM

#10

npccpartsman

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From: Stuttgart, Ar

Quote:

Originally Posted by cheezit

.3v ac the last one I checked.
I think tim needs to spend $10 at radioshack for an auto ranging meter

I'm going to check it with my old faithful that wifey has at work. What was weird with the meter I'm using (200v AC scale OR 750v AC scale) is that I had 25v AC before the alternator came on--battery voltage was 12.12v DC truck running/warming. I thought that was really weird. As soon as the alternator energized it jumped to 14.43v DC and 31.8v AC. This is with a new rebuilt alterator--new regulator, 200A stator and HD 70A 8 diode bridged rectifier. This setup doesn't seem to put out as much at idle as I can hear my fuel pump speed up when RPM's come up a touch or maybe the other alternator was maxed out. Still..........

I'm going to anally clean all the connections today at the starter, block, alternator, GPCM and both batteries and apply dielectric grease. This crap is driving me crazy.

Dec 16, 2010 | 10:04 AM

#11

caere

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Joined: Nov 2007

Posts: 400

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From: Canada

I checked mine. Had 14.18V passenger side, and 14.16 driver side.

AC 1st reading was 4.2 passenger and 2.9 drivers.
2 mins. later did another reading. DC voltage stayed the same but:
1.2 passenger and 0.9 drivers.

Now I'm confused lol? Would the change be something not working consistently in alternator? When I have changed batteries out it's always the passenger side that is the weaker of the two.

Dec 16, 2010 | 01:42 PM

#12

npccpartsman

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Joined: Dec 2003

Posts: 15,369

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From: Stuttgart, Ar

I think this link might provide a good explanation for what's going on: Car Battery and AC Voltage - The Garage Journal Board

Thanks to Maxium4x4 for the find.

At least my battery terminals and cables are nice and clean now.

Dec 16, 2010 | 06:19 PM

#13

cheezit

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Joined: Oct 2009

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From: N. Fort Worth, tx

seems to be a meter isuue thats funny. I love my 88

Dec 16, 2010 | 08:20 PM

#14

bismic

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Well, my Craftsman meter will not display properly either. I get about 2.4V or .24V with the decimal point alternating back and forth.

That being said, the meter is also an inductive ammeter, so I did a test I was wanting to do for some time:

W/ the lights on, radio on, and AC at max, I checked my alternator output. It was 63 amps at idle (800 rpm).