18 volts at the battery (again)!!!! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

kxnomore · 01-22-2008, 07:24 AM

I had this problem a while back and changed over to the internal regulator kit. Everything was good for a while, but this morning it's happening again.

Everything connection wise checks out okay, but it is applying full amperage to the battery at all times. Even disconnecting the plug on the top of the alternator doesn't make any difference. Neither does undoing the jumper wires at the old regulator connection. If the truck is running the amp gage is pegged all the way to the right.

So it's done this with both types of alternators, and with all new charging system parts.

Anybody have any ideas? Harness problems maybe???

89 crew · 01-22-2008, 07:53 AM

Have you checked with a different gauge? If it isn't a bad gauge then it has to be either a damaged regulator, or the wire connecting to the regulator back to battery check it for resistance.

8696steve · 01-22-2008, 11:06 AM

I you are not running a single wire alt, then I would suggest that the two wire are backwards. If the truck sits for a while and the battery goes dead it is definitely the two wires one to the regulator and one to the ignion switch that are criss crossed.

70' GMC · 01-22-2008, 11:10 AM

I thought it was 12 volts for the battery, I think that would be good then have amps added into the truck

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Sweet72 · 01-22-2008, 11:25 AM

Your ammeter indicates the load that is on the system. A short is seen as a "load" by the ammeter and will peg or at least cause it to indicate a high current draw. I'd start by pulling and reinstalling the fuses one at a time and watch the ammeter. A fuse will blow if it's rated current is exceeded. It may be an "unfused" circuit. There may be a chaffed wire somewhere that's causing an intermittent short to ground. Inspect your wiring and fuse block. I don't think it's your alternator install. Ever heard the story of the guy who replaced a blown fuse in his jeep with a .22 long rifle shell?

kxnomore · 01-23-2008, 06:51 AM

Quote:

Originally Posted by Sweet72

Your ammeter indicates the load that is on the system. A short is seen as a "load" by the ammeter and will peg or at least cause it to indicate a high current draw. I'd start by pulling and reinstalling the fuses one at a time and watch the ammeter. A fuse will blow if it's rated current is exceeded. It may be an "unfused" circuit. There may be a chaffed wire somewhere that's causing an intermittent short to ground. Inspect your wiring and fuse block. I don't think it's your alternator install. Ever heard the story of the guy who replaced a blown fuse in his jeep with a .22 long rifle shell?

That's probably it. I did take the alternator back and their tester was broken, so they gave me a new one free, which is cool.

So now the battery is reading 14.5 volts while running, but the ammeter gage is still showing a high charge rate. The battery is also bubbling a bit still. It reads about 13.2 volts sitting, so it still is getting overcharged, I think. All the fuses are good, nothing blown.

I'll go out tonight and disconnect the heater wiring, as that looked jury rigged from the PO. The heater is working just fine, though. So if it's a short that's causing a high load, can that tracked down with an ammeter? Could I check the amps with the key turned on but not running? Is that just putting an amp meter between the negative terminal (disconnected) and the battery? and turn the key and see what happens?

**truckdude239** · 01-22-2008, 12:16 PM

first time to check is the gage a bad gage will cause this problem seeing that the gage tells the voltage reg what to do. if u undid the jumper down at the external reg then u unhooked gage from the new reg so that should leave the gage out(ie mean the gage isn't the problem. i'd pull the alternator and take it to a parts house and have it tested just o make sure u didn't get a bad one

Sweet72 · 01-22-2008, 12:22 PM

When did the ammeter start tellin' the voltage reg what to do? Bossy little gauge...

72BLUZ · 01-22-2008, 12:42 PM

sound like the voltage regulator took a dump!!

**truckdude239** · 01-22-2008, 09:07 PM

the volt meeter or idiot light lets the volteage reg what to do heres is some tips

01-22-2008, 07:24 AM	#1
kxnomore Registered User Join Date: Dec 2006 Location: CA Posts: 331	18 volts at the battery (again)!!!! I had this problem a while back and changed over to the internal regulator kit. Everything was good for a while, but this morning it's happening again. Everything connection wise checks out okay, but it is applying full amperage to the battery at all times. Even disconnecting the plug on the top of the alternator doesn't make any difference. Neither does undoing the jumper wires at the old regulator connection. If the truck is running the amp gage is pegged all the way to the right. So it's done this with both types of alternators, and with all new charging system parts. Anybody have any ideas? Harness problems maybe???

01-22-2008, 07:53 AM	#2
89 crew Registered User Join Date: Mar 2006 Location: Kansas Posts: 865	Re: 18 volts at the battery (again)!!!! Have you checked with a different gauge? If it isn't a bad gauge then it has to be either a damaged regulator, or the wire connecting to the regulator back to battery check it for resistance.

01-22-2008, 11:06 AM	#3
8696steve Junior Member Join Date: Aug 2006 Location: California Shasta County Posts: 109	Re: 18 volts at the battery (again)!!!! I you are not running a single wire alt, then I would suggest that the two wire are backwards. If the truck sits for a while and the battery goes dead it is definitely the two wires one to the regulator and one to the ignion switch that are criss crossed. __________________ 1970 C10 Short fleet side. For sale http://cgi.ebay.com/ebaymotors/ws/eB...MESE:IT&ih=017 Last edited by 8696steve; 01-22-2008 at 11:07 AM.

01-22-2008, 11:10 AM	#4
70' GMC HERE.......Somewhere Join Date: Oct 2006 Location: Birmingham AL Posts: 2,488	Re: 18 volts at the battery (again)!!!! I thought it was 12 volts for the battery, I think that would be good then have amps added into the truck. __________________ Current rides: 2013 Hyundai elantra gt DD 1995 camaro my first crush lmao Was: 1970 with a 350 4barrel and 288 horses Classics make it possible!

01-22-2008, 11:25 AM	#5
Sweet72 Registered User Join Date: Nov 2003 Location: Alexandria, VA Posts: 1,534	Re: 18 volts at the battery (again)!!!! Your ammeter indicates the load that is on the system. A short is seen as a "load" by the ammeter and will peg or at least cause it to indicate a high current draw. I'd start by pulling and reinstalling the fuses one at a time and watch the ammeter. A fuse will blow if it's rated current is exceeded. It may be an "unfused" circuit. There may be a chaffed wire somewhere that's causing an intermittent short to ground. Inspect your wiring and fuse block. I don't think it's your alternator install. Ever heard the story of the guy who replaced a blown fuse in his jeep with a .22 long rifle shell? __________________ '72 GMC SWB C1500 Custom, frame-off in progress. 383 SBC, 9:1CR, Comp Cams XE262H, Scat internal balanced crank, Eagle SIR 6" rods, Keith Black dish pistons, Dart Iron Eagle 72/180 heads, Weiand Stealth intake, Stewart stage I water pump, Holley 4bbl vac sec, TH350 with B&M Shift Improver Kit. 12 bolt positraction. Last edited by Sweet72; 01-22-2008 at 11:39 AM.

01-22-2008, 12:16 PM	#7
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,237	Re: 18 volts at the battery (again)!!!! first time to check is the gage a bad gage will cause this problem seeing that the gage tells the voltage reg what to do. if u undid the jumper down at the external reg then u unhooked gage from the new reg so that should leave the gage out(ie mean the gage isn't the problem. i'd pull the alternator and take it to a parts house and have it tested just o make sure u didn't get a bad one __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube

01-22-2008, 12:22 PM	#8
Sweet72 Registered User Join Date: Nov 2003 Location: Alexandria, VA Posts: 1,534	Re: 18 volts at the battery (again)!!!! When did the ammeter start tellin' the voltage reg what to do? Bossy little gauge... __________________ '72 GMC SWB C1500 Custom, frame-off in progress. 383 SBC, 9:1CR, Comp Cams XE262H, Scat internal balanced crank, Eagle SIR 6" rods, Keith Black dish pistons, Dart Iron Eagle 72/180 heads, Weiand Stealth intake, Stewart stage I water pump, Holley 4bbl vac sec, TH350 with B&M Shift Improver Kit. 12 bolt positraction. Last edited by Sweet72; 01-22-2008 at 12:23 PM.

01-22-2008, 12:42 PM	#9
72BLUZ Registered User Join Date: Nov 2006 Location: lafayette, ga. Posts: 832	Re: 18 volts at the battery (again)!!!! sound like the voltage regulator took a dump!! __________________ Freedom is never more than one generation away from extinction. We didn't pass it to our children in the bloodstream. It must be fought for, protected, and handed on for them to do the same.... Ronald Reagan

01-22-2008, 09:07 PM	#10
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,237	Re: 18 volts at the battery (again)!!!! the volt meeter or idiot light lets the volteage reg what to do heres is some tips __________________ David fuller Ase Certified Mechanic Click here to help support our board!! 1971 Chevy c-10 under going a 4.8l LSx swap Build Thread http://67-72chevytrucks.com/vboard/s...d.php?t=421305 2007 Honda Accord my daily 145kmiles 2002 Honda Accord 4 door With 330k(sisters car) 2005 toyota Avalon 228k( brothers car) 2002 Sububran 5.3 245k 2000 Tahoe 5.3l 378 General manager for Marco's Carwash & lube



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