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Fluctuating voltage

Anthonyb1969

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Is it normal for the voltage to fluctuate from 12.0 to14.0 while going down the road?
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Friday2322

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Is it normal for the voltage to fluctuate from 12.0 to14.0 while going down the road?
Mine will read anywhere from about 13.5 to 14.5 driving around, it just depends on how long it sits in the garage before I drive it. It's not a daily driver so once a week I'll put the smart charger on it.
 

Capricorn

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12.0 is low. Around 12.7 to 14.7 is what I see.
Pushing the pedal shows around 12-13+ volts, and releasing the pedal shows around 14.2 - 14.7 for me.
I believe one is the reading from the alternator, and the higher one from the battery.
 
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Anthonyb1969

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I just talked to a service manager for Jeep he said this is a smart charging system it only takes what charge it needs and the volt meter will fluctuate.
 

BuffaloBill

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Just to expand on the smart charging, I believe it’s done for fuel economy benefit. It seems to take advantage of off-throttle conditions, charging hard then, and backing off on alternator field current when on-throttle.
 

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Ruby Clatterbox

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Yeah, throw out anything you know about charging systems with the new Jeeps. I thought mine was going crazy when I first looked at the gauge, but if it keeps working, it actually makes sense to charge on decel not creating parasitic loss on the engine when accelerating.
 

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Very normal....
 

Gorilla57

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Completely normal.

Smart alternators= throw out everything you thought you knew about 12v charging.
Yup, and if you really wanna complicate things.......get the Ram 2500/3500/etc trucks with the dual alternators. My dad's 3500 constantly charges above 14.1 even though it is supposed to have smart alternators. From what he has been able to figure out, the BCM (or what ever controls the alternators) is programmed differently for his setup since most people ordering the duals has an electrical need for that many amps. He was causing his DC-DC charger to shut down as he had it set up for a smart system. Now that he's got it set up for a "constant" alternator, it charges the 5th wheel correctly. Things that FCA doesn't bother to tell you.
 
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Anthonyb1969

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Thanks everyone. Picked up the Jeep at dealership. All though it did show a low voltage code they said there was nothing wrong with the system. So I’ll just keep driving it until I can’t drive it anymore. I know from experience in the semi world that most of these so called mechanics are part changers today and not problem solvers..
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