24V Alternator Charging Volts

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rdh778
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Posts: 28
Joined: Fri Aug 27, 2021 5:30 pm
Location: Wappingers Falls, NY 12590

24V Alternator Charging Volts

Post by rdh778 » Wed May 18, 2022 4:52 am

My alternator is charging at 23.78 V. Is that adequate to charge my batteries or does it need to be charging at 26-28 V? My 1967 M151A1 is not turning over enough to start and the batteries do not get charged enough to keep them over 12 V each. They usually stay at about 11.75 V and that is not enough to start it. My problem is I don't know if the alternator or the batteries (which are about 2 years old) is bad.
Any help is appreciated.
Thanks,
Bob


Rickf
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Location: Pemberton, New Jersey

Re: 24V Alternator Charging Volts

Post by Rickf » Wed May 18, 2022 5:23 am

A 67 A1 would normally have a 25 amp generator on it unless someone converted it over to the later 60 amp alternator. But either way the charging voltage you are showing is exactly the same as the dead battery voltage, in other words the charging system is not working. It should be charging at 28 volts. And a battery at 11.75 volts is completely dead, it is not just low.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

rdh778
G-Corporal
G-Corporal
Posts: 28
Joined: Fri Aug 27, 2021 5:30 pm
Location: Wappingers Falls, NY 12590

Re: 24V Alternator Charging Volts

Post by rdh778 » Sun Jun 05, 2022 2:46 pm

Thanks for your reply. Turns out my alternator has an adjustment and it was turned all the way down. Live and learn.

Rickf
G-Lieutenant General
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Posts: 5645
Joined: Sun Mar 19, 2006 12:04 pm
Location: Pemberton, New Jersey

Re: 24V Alternator Charging Volts

Post by Rickf » Sun Jun 05, 2022 3:17 pm

I had sent you a pm on 5/18 but you never picked it up. An A1 would not normally have an alternator so I explained all of your options.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone


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