I measure 12.4 v across the battery with the engine off. I start it....12.4v too. Hmmmm. I'm thinking it needs a VR. I swap on a new mechanical type then start it up.

The ammeter shows a charge, the voltage across the battery is 12.9 at idle, then bumps up to 13.1 + at 1500 rpm.

Does this sound about right for an ole 65 1 wire alt?

A bit low, but make sure the battery is charged up before measuring voltage.

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Ed
64 Valiant 225 / 904 / 42:1 manual steering / 9" drum brakes

No. Your charging voltage is low. Another bad regulator, faulty wiring, a slipping belt and/or a faulty alternator.

(BTW, a fully-charged "12 volt" battery should show not less than 12.6 volts.)

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Make sure your meter is reading correctly - hate too see you chase parts when the meter is slightly out of calibration

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The car I am restoring is a 1971 Valiant 4 door with a slant 6 - 225 engine.

Its a Fluke digital, so I'm pretty sure its fine.

The battery may not be fully charged, I'll charge it up.

The wiring harness on this car was hacked into multiple times in multiple locations. I'm limping through this one. I'm also pretty sure the belt is not tight enough, easy enough fix.

thanks for the replys!
Mike

any battery with 12.3 volts or less is "sulfating" it self
and is verry much in need of a good charge.

12.6 is the bare minimum your battery should ever rest at
to be concidered "charged up"

the new agm / gell cell batterys generaly rest around 13.1 volts

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1972 Plymouth Valiant / slant 6 auto