charging problem need help

[bob1967]

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]

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]

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]

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]

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]

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]

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.