Possible Alternator Problem

[Lilfarmrboy]

Okay guys anyone know what the voltage is supposed to be when the truck is running at idle? My radar detector has been warning me of low voltage issue off and on now for about a month. When I start the truck my SCT Livewire shows the voltage around 11.5 to 11.8 then after I hit the accelerator it then climbs to 13.5 give or take a few. What should it be when the truck is at idle? Could it be my alternator or could my batteries be getting weak? I don't want no low voltage condition, the last thing I need is to start replacing electronics such as the FICM.

[Lilfarmrboy]

Oh and I should add that so far it has not affected my truck in the slightest. Truck fires right up first time with no long start that so many others have.

[caissiel]

It is normal to see 11.5 volts after startup because there is delay that protects the alternator when the glow plugs kick in and the fuel heater is on. It will go up to 14.2 when batteries are low and settle at 13.5-13.6. I have 2 new batteries and that is what I read this morning in Florida.

[Galaxie]

Very normal volts. Just as stated above, alt doest kick on for a bit.


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[Lilfarmrboy]

Thanks for the info guys! Just wasn't sure and didn't know if I have a problem or not. I learn more from this site than I do from any other website I visit. :-)