charging problem need help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

bob1967 · 10-28-2008, 11:15 PM

I replaced the battery, alternator, and voltage regulator, confused now. It will start off a charger the lights are bright then a few miles down the road they start dimming, park truck try to restart no luck. Please help. Thanks in advance

**kwmech** · 10-29-2008, 12:16 AM

Have the battery load checked. I got a run of batterys years ago that were filled with mostly water---very little electrolite. Made bizarre electrical gremlims

**truckdude239** · 10-29-2008, 06:15 AM

i'd replace all of them with an internal reg alt more stable more amps had this problem with my truck with new alt and reg heres the link to the swap External reg to internal reg swap

69rut · 10-29-2008, 06:33 AM

I chased a simular problem two years ago.

Check the wire from the battery to the gen/alt. Mine had a connector in it that was lose. So basically the battery was not getting charged. Replaced that wire with a new wire, one piece and solved the problem.

68gmsee · 10-29-2008, 09:20 AM

Also, while it's running put a voltmeter across the battery, it should have 13 plus volts going to it. Not sure of the the exact voltage it should read but IIRC mine read about 13.5 volts last time I checked.

If it's charging properly, there should be enough juice to run your truck after you start it even with a bad battery. However, you could have an internally shorted battery that could cause you grief.

Replace the battery cables (cheap insurance) cause they can corrode and break internally and may not be visible.

And don't overlook defective new parts. I also got a defective volt reg once from the parts store.

bob1967 · 10-29-2008, 01:18 PM

Thanks for the help, I am going to go with a 1 wire alt just waiting for the rebuild of the truck. Right now a friend is borrowing the truck. He is taking it to oriellys and have them load test and test the alt. It has always ran at 12 volts or a little less, never over that

Thanks again for the help Bob

PanelDeland · 10-29-2008, 01:31 PM

A fully charged battery new should show about 13.2 volts.2.2 volts per cell.If the alt isn't charging at least 12.6-13.5 something isn't right.The new 13.2 will drop some over time but should stay above 12 all the time or the battery is probably bad or is not being charged normally.
If the truck will not start unless it's on the charger,I would first suspect the battery of having an internal short.Even a bad battery with a full charge should start it.A battery with an internal short may be grounding out causing the voltage to be pulled down.

10-28-2008, 11:15 PM	#1
bob1967 Registered User Join Date: Nov 2007 Location: peaster, texas Posts: 71	charging problem need help I replaced the battery, alternator, and voltage regulator, confused now. It will start off a charger the lights are bright then a few miles down the road they start dimming, park truck try to restart no luck. Please help. Thanks in advance

10-29-2008, 12:16 AM	#2
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,628	Re: charging problem need help Have the battery load checked. I got a run of batterys years ago that were filled with mostly water---very little electrolite. Made bizarre electrical gremlims

10-29-2008, 06:15 AM	#3
truckdude239 Senior Member Join Date: Sep 2005 Location: Lewisville, Nc Posts: 10,237	Re: charging problem need help i'd replace all of them with an internal reg alt more stable more amps had this problem with my truck with new alt and reg heres the link to the swap External reg to internal reg swap __________________ 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

10-29-2008, 06:33 AM	#4
69rut Registered User Join Date: Sep 2006 Location: SE Virginia Posts: 158	Re: charging problem need help I chased a simular problem two years ago. Check the wire from the battery to the gen/alt. Mine had a connector in it that was lose. So basically the battery was not getting charged. Replaced that wire with a new wire, one piece and solved the problem. __________________ trailers are for boats

10-29-2008, 09:20 AM	#5
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: charging problem need help Also, while it's running put a voltmeter across the battery, it should have 13 plus volts going to it. Not sure of the the exact voltage it should read but IIRC mine read about 13.5 volts last time I checked. If it's charging properly, there should be enough juice to run your truck after you start it even with a bad battery. However, you could have an internally shorted battery that could cause you grief. Replace the battery cables (cheap insurance) cause they can corrode and break internally and may not be visible. And don't overlook defective new parts. I also got a defective volt reg once from the parts store.

10-29-2008, 01:18 PM	#6
bob1967 Registered User Join Date: Nov 2007 Location: peaster, texas Posts: 71	Re: charging problem need help Thanks for the help, I am going to go with a 1 wire alt just waiting for the rebuild of the truck. Right now a friend is borrowing the truck. He is taking it to oriellys and have them load test and test the alt. It has always ran at 12 volts or a little less, never over that Thanks again for the help Bob Last edited by bob1967; 10-29-2008 at 01:20 PM. Reason: add to

10-29-2008, 01:31 PM	#7
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,992	Re: charging problem need help A fully charged battery new should show about 13.2 volts.2.2 volts per cell.If the alt isn't charging at least 12.6-13.5 something isn't right.The new 13.2 will drop some over time but should stay above 12 all the time or the battery is probably bad or is not being charged normally. If the truck will not start unless it's on the charger,I would first suspect the battery of having an internal short.Even a bad battery with a full charge should start it.A battery with an internal short may be grounding out causing the voltage to be pulled down. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"



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