Charging voltage seems too high, is voltage regulator adjustable? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

car10107 · 07-12-2021, 04:05 PM

I've had my 65 C10 283 for a couple of years now. It has an aftermarket ammeter that always reads close to the center so I have never worried about the charging system. I recently started using one of those digital volt meter/USB ports plugged into my cigarette lighter socket to charge my phone. This particular tech will cause the voltage reading to flash if it goes below 11 or above 15. I notice that when I am driving my voltage runs between 15.3-15.7 and this seems a little high? Key on engine off voltage is like 12.8 and engine idling is around 13.8 but when the RPM's come up and the alternator is spinning faster, the volts goes above 15. I remember some of the older voltage regulators were adjustable but wanted to ask before buying a new one. I want to stay with the OE external regulator setup for now. Thanks

**LostMy65** · 07-12-2021, 07:44 PM

I'm not sure if it's adjustable in itself.
But you are correct that 15 is too high:
https://askinglot.com/what-causes-an...t-high-voltage

**Steeveedee** · 07-12-2021, 07:59 PM

Yes. See page 6Y-11 in this manual-

http://www.mediafire.com/file/e7v2am...Truck.pdf/file

Download that thing!

**Wrenchbender Ret** · 07-13-2021, 11:44 AM

The original Delco reg. is adjustable with a screw at the base of the spring on the voltage side of the reg. After market regs. adjust by bending the tab that holds the spring.
The voltage will drop about .2 volts when you put the cover on.
George

07-12-2021, 04:05 PM	#1
car10107 Registered User Join Date: Sep 2020 Location: THORNTON CO Posts: 25	Charging voltage seems too high, is voltage regulator adjustable? I've had my 65 C10 283 for a couple of years now. It has an aftermarket ammeter that always reads close to the center so I have never worried about the charging system. I recently started using one of those digital volt meter/USB ports plugged into my cigarette lighter socket to charge my phone. This particular tech will cause the voltage reading to flash if it goes below 11 or above 15. I notice that when I am driving my voltage runs between 15.3-15.7 and this seems a little high? Key on engine off voltage is like 12.8 and engine idling is around 13.8 but when the RPM's come up and the alternator is spinning faster, the volts goes above 15. I remember some of the older voltage regulators were adjustable but wanted to ask before buying a new one. I want to stay with the OE external regulator setup for now. Thanks __________________ 1965 Chevy C10 283 SM420 Long Fleet "The Old Man" 1970 Chevy C10 350 SM465 Long Fleet "Dave" 1975 Toyota FJ40 "Mr Grinch" 1969 Pontiac Firebird 2001 Chevy Tahoe 2001 Toyota 4Runner

07-12-2021, 07:44 PM	#2
LostMy65 But Found Her 25yrs Later! Join Date: Oct 2010 Location: Oregon City, Oregon Posts: 10,507	Re: Charging voltage seems too high, is voltage regulator adjustable? I'm not sure if it's adjustable in itself. But you are correct that 15 is too high: https://askinglot.com/what-causes-an...t-high-voltage __________________ I lost my 65 - Found it 25 years later: http://67-72chevytrucks.com/vboard/s...d.php?t=426650 66 C20 Service Truck: http://67-72chevytrucks.com/vboard/s...d.php?t=428035

07-12-2021, 07:59 PM	#3
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,169	Re: Charging voltage seems too high, is voltage regulator adjustable? Yes. See page 6Y-11 in this manual- http://www.mediafire.com/file/e7v2am...Truck.pdf/file Download that thing! __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

07-13-2021, 11:44 AM	#4
Wrenchbender Ret Registered User Join Date: Oct 2005 Location: Overland Park, Ks. Posts: 5,193	Re: Charging voltage seems too high, is voltage regulator adjustable? The original Delco reg. is adjustable with a screw at the base of the spring on the voltage side of the reg. After market regs. adjust by bending the tab that holds the spring. The voltage will drop about .2 volts when you put the cover on. George



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