Hey you electrical guru's- need help with a charging question

So I hooked up my volt meter in my 32 and its showing 15 volts. This concerns me because it seems high. I took my internally regulated alternator in and had it tested...it tested good. Is 15v normal? My understanding is 14 v is normal. Is my alternator starting to go bad?? Its a standard GM alternator. Let me know your thoughts.

 

It's fine.

 

sounds OK
Could measure with test multimeter.
should drop when you turn on headlights.
wouldnt alarm me

 

15v is fine. A fully charged, 12V battery is actually 13.2V and the alt has to go higher than that to get it to charge.

Regulator usually set for 14.5V but 15 is close enough. Your meter may be reading a touch high.

 

Check your battery too! I've found over charging will ruin a good battery fast. Good luck.

 

Thanks for the info everyone.

 

Is it 15V across the battery as the vehicle is running also? Is the voltmeter an old restored unit, a modern unit?

 

Is it an external regulator?

If so you need to measure the voltage between the B terminal on the Alternator and the Gen term on the regulator, it should be 0. That is where the regulator senses voltage,

If there is resistance in that line you could fool the regulator.

Remember the regulator has a thermistor which changes charging voltage according to temperature.



Hoop

 

14.7 is normal. You VM might be off some?

 

I have one last thought. Would running a magneto give a slightly higher volt reading due to lack of power draw for the ignition system. This is the first time I have ever used a Mag.

 

Hoop98 is right on with the temp.affecting voltage.

Griffin Auto Electric

 

13.8 to 15.2 for years was the standard..
Gerry

 

worry about it if it boils water out of the battery, should be fine though

 

My old 10si alternator started showing a slight glow on the idiot light, that at night you could see. It had never done that before, so i checked the battery voltage when running and it read 15.3 volts. When the light would go out it read 14.7. Turned out to be the DIODE TRIO, which is an easy fix in the 10 and 12si alternators. Hope this helps. (And, yes, it did charge, but that faint glow of the light bugged me, so I wanted it fixed. Idiot parts person at Buick didn't even know about the diode trio.)

 

i would not worry about the 15v.. you may check the battery a bad or low battery can cause some overcharge readings

 

I would say that you are probably ok at 15V. The problem is that the diodes are probably going bad and that's why you are over spec at 15 instead of 14.5. A few bucks at the parts store, a paper clip and half an hour and you can replace the diodes and you know you are good to go for a really long time.

I just don't like my stuff running on the ragged edge of ok. I would prefer it was well within range so I can depend on it without a thought of it failing when I need it. I also replace batteries when they start dragging down the starter, long before I go out to the car, turn the key and hear *click*.

Just saying.

 

Thanks!

 

15 is coolOl Deuce