Battery Voltage - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**53burb** · 08-30-2004, 11:46 AM

I know we have gone over this before, but what should the voltage at the battery be while it is running or not running?? I read 12.5 volts running or not. The alternator was reading 12.5 also at the battery terminal. Shouldn't it read 14.5 volts?? Is it different with an external regulator?? It is a 350 with an externally regulated alternator??
Thanks...
Chris

JimKshortstep4x4 · 08-30-2004, 11:56 AM

With the engine running you should be getting 14.5 volts at approx. 1200 rpm.

If you don't get 14.5 approximately then your regulator could just need adjusting. I know the internally regulated alternators have some advantages but externaly regulators do work and some of my vehicles still have the external regulator.

I can fax you the instructions for adjusting the regulator if you like.

Jim

**53burb** · 08-30-2004, 12:24 PM

Pleae fax me the instructions @ 480-715-9009...If it only needs adjusting thats fine, if it needs replacing, then I will swap to an internally regulated alternator. I do believe the alternator is on its way out. I can hear it when the engine is running at idle.

Longhorn Man · 08-30-2004, 03:24 PM

Chances are, the regulator or alt is dead. The regulator is a very cheap part...like 12 bucks or something...but personally, I'd go and spend the 12 bucks at the junk yard for a later internally regulated deal.

**53burb** · 08-30-2004, 07:09 PM

Thanks for the answers. I know that there is someone that did this swap by connecting some wires at the plug into the regulator and not using one. Does anybody have that link??

JimKshortstep4x4 · 08-30-2004, 08:13 PM

Did you get the faxed instructions on the regulator? My Fax machine indicated that it went through.

Jim

68w/sbc406 · 08-30-2004, 08:30 PM

down at the plug to the regulator i hooked the brown and blue together and left the red and white pluged in. also had to run a bigger wire from the alternator to the battery but i did some rewiring so it might have been because of that.

**53burb** · 08-31-2004, 10:55 AM

I did receive the fax. I stopped by Checkers yesterday, they confirmed that there is a problem with the charging system. According to the PO, the alternator has been replaced within the last few years. It may be the regulator. However, I am going to replace both units with an internally regulated unit.

**53burb** · 08-31-2004, 07:41 PM

I didn't have time to finish my post earlier. But anyways, thanks for the replys and the fax...
Chris

08-30-2004, 11:46 AM	#1
53burb Registered User Join Date: May 2004 Location: Queen Creek, AZ Posts: 1,004	Battery Voltage I know we have gone over this before, but what should the voltage at the battery be while it is running or not running?? I read 12.5 volts running or not. The alternator was reading 12.5 also at the battery terminal. Shouldn't it read 14.5 volts?? Is it different with an external regulator?? It is a 350 with an externally regulated alternator?? Thanks... Chris

08-30-2004, 08:30 PM	#7
68w/sbc406 Got Light Emitting Diode? Join Date: Apr 2004 Location: Newberg, OR Posts: 2,485	down at the plug to the regulator i hooked the brown and blue together and left the red and white pluged in. also had to run a bigger wire from the alternator to the battery but i did some rewiring so it might have been because of that. __________________ 1968 1/2 ton 2wd lwb 6 lug disc and bags up front. Next c notch and rear bags '02 Chevy Silverado LT ext cab short bed 2WD 5/7 drop on 22's(the family car) 1993 Cherokee work ride/weekend wheeler

08-30-2004, 11:56 AM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	With the engine running you should be getting 14.5 volts at approx. 1200 rpm. If you don't get 14.5 approximately then your regulator could just need adjusting. I know the internally regulated alternators have some advantages but externaly regulators do work and some of my vehicles still have the external regulator. I can fax you the instructions for adjusting the regulator if you like. Jim

08-30-2004, 12:24 PM	#3
53burb Registered User Join Date: May 2004 Location: Queen Creek, AZ Posts: 1,004	Pleae fax me the instructions @ 480-715-9009...If it only needs adjusting thats fine, if it needs replacing, then I will swap to an internally regulated alternator. I do believe the alternator is on its way out. I can hear it when the engine is running at idle.

08-30-2004, 03:24 PM	#4
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Chances are, the regulator or alt is dead. The regulator is a very cheap part...like 12 bucks or something...but personally, I'd go and spend the 12 bucks at the junk yard for a later internally regulated deal.

08-30-2004, 07:09 PM	#5
53burb Registered User Join Date: May 2004 Location: Queen Creek, AZ Posts: 1,004	Thanks for the answers. I know that there is someone that did this swap by connecting some wires at the plug into the regulator and not using one. Does anybody have that link??

08-30-2004, 08:13 PM	#6
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	Did you get the faxed instructions on the regulator? My Fax machine indicated that it went through. Jim

08-31-2004, 10:55 AM	#8
53burb Registered User Join Date: May 2004 Location: Queen Creek, AZ Posts: 1,004	I did receive the fax. I stopped by Checkers yesterday, they confirmed that there is a problem with the charging system. According to the PO, the alternator has been replaced within the last few years. It may be the regulator. However, I am going to replace both units with an internally regulated unit.

08-31-2004, 07:41 PM	#9
53burb Registered User Join Date: May 2004 Location: Queen Creek, AZ Posts: 1,004	I didn't have time to finish my post earlier. But anyways, thanks for the replys and the fax... Chris



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