M35A2 Charging system questions

Okay my m35 has been hard to start lately because the batteries are dyeing fast. I took them out the other day and charged right up. Put them back in and put a volt meter to the slave cable receptacle and it measured 24.9 Volts (after charge) So i got it running again and put the volt meter on the big wire coming off the Generator(the wire going under the generator cover) and it said 24.99 volts.

My question is how do i check the generator to see if its working properly? And i adjusted the Allen bolt on top of the gen. to see if the reading would change but i did not.

My voltage gauge stays about in the yellow regardless if the switch is on or the engine is running.

Heres some pics below

Thanks guys.
Corey

It's not charging if there was no increase in battery voltage, when running.

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Thank you

The voltage adjustment is done with the pot. under that allen plug, not with the plug itself.

Hey Corey,
I don't know if this is normal, but my voltage meter always runs at the top of the green, not the bottom.

My battery would get low after a week of driving. I had pretty much decided the alternator was dead.
One day I got motivated to test it. I charged the battery's started the truck and there was no voltage increase.

so figuring i had nothing to lose I turned the screw under the plug and my voltage jumped up over 30 volts.
Turned it down to about 28.5 volts and all is well.

I also found that my voltage gauge is off. If you get it charging set the voltage with a volt meter on the battery's then note where you gauge is. That will be you normal charging point. Mine is also top of the green.

Thats funny John, when my gauge is on the white tick mark in the green, it is 28.8. Right on the money!

gimpyrobb said:

Thats funny John, when my gauge is on the white tick mark in the green, it is 28.8. Right on the money!

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Why is it I that always has the broken or defective stuff?

Am I not a good person?

Don't I love my Mom?

Oh well, I'll be happy for you even though you stupid gauge reads right and mine doesn't.

PS
By the way Mr Gimp. That cut of axle shaft you sent me was just the ticket. Thanks

My pleasure! Just so you know, the air pressure, oil pressure, and voltage are the only gauges that work in my truck.

I took the allen head off the generator and plugged the voltmeter up to the wire and still read 24.9 volts either way i turned the pot on the generator. Im guessing the gen. has failed. Im trying to find places to rebuild them around my area. In winston-salem NC area

-Corey

I took the allen head off the generator and plugged the voltmeter up to the wire and still read 24.9 volts either way i turned the pot on the generator. Im guessing the gen. has failed. Im trying to find places to rebuild them around my area. In winston-salem NC area

-Corey

A trick that may work for you is to use your batteries to start the truck, and then shut off the accessory switch. It may provide marginal benefit to you, but if you're running the truck during the day, and the generator isn't giving you juice, then you're draining your batteries by running your in-tank fuel pump. Shut off the accessory switch (after warm-up) and your truck is running on zero electricity. Make your own decision about running lights/brake lights. Battery drain is marginal if you're not using headlights.

Sounds like you have an alternator problem. I would just double check all your connections, grounds, and belt tension before you remove it. When adjusted properly the niddle should be on the white tick.

If you fast foward to 1:34 it shows the batt gauge.
[media]http://www.youtube.com/watch?v=hGTSZEKQ9nk&feature=youtube_gdata_player[/media]

Thanks guys for helping me. What ive done is ive gone through the wires all good grounds and good wires. All connected.

Thanks for the video Steven! My needle is between the red and the green on the white line.

So im guessing its the Alternator. Right now im trying to locate a place around winston-salem that rebuilds them.

I have one question: what is that metal box on the drivers side with wires going into it? Its under the hood next to the secondary fuel filters?

Turn signal box, you'll need that!



Unless you don't make no turns!

phil2968 said:

Turn signal box, you'll need that!



Unless you don't make no turns!

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Thanks

I read online that the voltage should be adjusted to 27.6v. I haven't found it in the TM yet. Can anyone confirm or deny?

DavidWymore said:

I read online that the voltage should be adjusted to 27.6v. I haven't found it in the TM yet. Can anyone confirm or deny?

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It really depends on your batteries and your usage. At the transit agency we use "Odyssey" batteries which need to be charged at 30 volts. Most 24 volt systems though charge at 27 to 29 volts. I prefer setting it at 28 volts.

http://www.prestolite.com/pgs_support/trouble_shoot_1.php

28.0-28.4V per the alt manufacturer.