The Ford Barn

art ebeling · 08-27-2022, 10:45 AM

I am trying to check if the generator is working on a 48 pickup. With the key off the battery reads 6.25 volts. When the engine is started the digital voltmeter goes all over, just random numbers from 19.0 to 3.5volts and everywhere in between. With the engine running the meter reads like that if only one lead is connected to either battery post or to the engine block,generator arm terminal or touching anywhere on the engine. The generator guage does not show charging. What is going on? Art

JayChicago · 08-27-2022, 11:02 AM

Generators cause static that confuses digital instruments. Better to get an analog meter. However, I am able to use my digital meter to do basic things like measure voltage. You do need to have both instrument leads connected to get any kind of reading. If only one lead connected, all you see is the static.

You are able to measure voltage at the battery with engine not running. Do the same thing with engine running at medium RPM. If generator is charging your digital meter should show 7.0 to 7.5 volts.

Anteek29 · 08-27-2022, 11:16 AM

Best to use an analog meter.

Ken/Alabama · 08-27-2022, 05:38 PM

This might help

leon bee · 08-27-2022, 07:50 PM

Sponsored Links (Register now to hide all advertisements)

Disconnect battery and see if she keeps running?

08-27-2022, 10:45 AM	#1
art ebeling Senior Member Join Date: Dec 2014 Location: Hillsboro IL Posts: 479	checking generator on a 48 I am trying to check if the generator is working on a 48 pickup. With the key off the battery reads 6.25 volts. When the engine is started the digital voltmeter goes all over, just random numbers from 19.0 to 3.5volts and everywhere in between. With the engine running the meter reads like that if only one lead is connected to either battery post or to the engine block,generator arm terminal or touching anywhere on the engine. The generator guage does not show charging. What is going on? Art

08-27-2022, 11:02 AM	#2
JayChicago Senior Member Join Date: Jan 2019 Location: Chicago Posts: 732	Re: checking generator on a 48 Generators cause static that confuses digital instruments. Better to get an analog meter. However, I am able to use my digital meter to do basic things like measure voltage. You do need to have both instrument leads connected to get any kind of reading. If only one lead connected, all you see is the static. You are able to measure voltage at the battery with engine not running. Do the same thing with engine running at medium RPM. If generator is charging your digital meter should show 7.0 to 7.5 volts.

08-27-2022, 11:16 AM	#3
Anteek29 Senior Member Join Date: Dec 2014 Location: Santa Maria, CA Posts: 985	Re: checking generator on a 48 Best to use an analog meter. __________________ Alan 1929 Special Coupe 1941 Pick-Up 1955 Victoria

08-27-2022, 07:50 PM	#5
leon bee Senior Member Join Date: May 2017 Location: Arkansas Posts: 611	Re: checking generator on a 48 Sponsored Links (Register now to hide all advertisements) Disconnect battery and see if she keeps running?