gm alternator question...

Dennis Minn · Jul 31, 2019

All,

I have a home-made wiring harness for an old 1979ish truck. The alternator seems to be putting out too much voltage. I got 14.6 with the multimeter, as wellas the analog dashboard voltmeter, with engine running at idle.

It used to run aroung 13.5 volts, but seems to be giving out a whisker too much.

Attached is a chicken-scrathed drawing of the electrical. Please welcome cave=man remarks, as well as crayon coloring jokes. I am not in a hurry.

D.

Dennis Minn · Jul 31, 2019

here's picture of chicken scratch

Steve@Advance · Jul 31, 2019

That's not too high voltage.

Looks like it's wired right.

old · Jul 31, 2019

That reading is not to high it just show the battery is ether needing more volts put in or it , the battery that is could be going bad so it need more to keep it full charged

Dennis Minn · Jul 31, 2019

Steve,

It's a Chevy. It has been run with that wiring for a good number of years, however, I thought in my mind voltage was closer to 13 and a half. Mybe my mind is playing tricks. Thanks for you review and comment. I wasn't overl concerned, but I'd rather fall on the conservative side and ask ahead of time.

On another note, is it just me but posting a picture/photo takes some doing? Perhaps as well the delayed typing I tried to do.

D.

guido · Jul 31, 2019

Hello DEnnis minn,

Must be wired correctly, as you have not let the smoke out! If you have an open top battery, make sure the cells are covered with electrolyte. It would overcharge a bit if they are exposed. 13.8 to 14.2 volts is normal charging voltage, so not to far off.

Just snug up the mounting of the alternator to make sure it has a solid ground, as it needs a good ground for the regulator to work properly,

Guido.

grizz02 · Jul 31, 2019

load test the batt to see if its getting weak, most auto parts or shops can do it for you

Janicholson · Jul 31, 2019

That voltage is OK. If you saw lower voltage it might have been charging heavily into the battery when it was partially charged. When loaded doing its job, the volts will be lower. Jim

oldproudvet · Jul 31, 2019

Voltage will work fine. GM alternators of that period were charging sealed Delco side post batteries that require 14+ volts

Russ from MN · Jul 31, 2019

Our 13 Silverado is charging over 14, the dealer service dept. told me that's OK, it still has the original battery and hasn't burned out any bulbs, so I guess it's OK.

gm alternator question...

Dennis Minn

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Dennis Minn

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Steve@Advance

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old

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Dennis Minn

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guido

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grizz02

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Janicholson

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oldproudvet

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Russ from MN

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