[TooFaSS4u]

I have noticed since I bought my SD new last year that the Voltmeter is sporadic. One minute it will show ~9-10 volts and then after a bit will show ~14. This doesn't happen quickly like when I push the gas the meter goes up or anything. Have had no other signs of alternator or battery trouble. Just wondering if this is normal?

 

[Ginger]

there is a regulator, so when it hits a certain point, say 11.5 volts it will charge till it hits 14.5, then stop charging, once it drops down again to the 11.5 it will charge again and repeat the cycle,

this way nothing gets over charged

 

[Thewes]

there is a regulator, so when it hits a certain point, say 11.5 volts it will charge till it hits 14.5, then stop charging, once it drops down again to the 11.5 it will charge again and repeat the cycle,

this way nothing gets over charged

I wonder if this would effect the bank of batteries I have for my car audio system.

 

[GCncsuHD]

there is a regulator, so when it hits a certain point, say 11.5 volts it will charge till it hits 14.5, then stop charging, once it drops down again to the 11.5 it will charge again and repeat the cycle,

this way nothing gets over charged

Something like this, although I didn't think it was supposed to drop that low, like maybe 12.Xv or something. Its a common thing with 05 up trucks I think, I can't remember what year they went to that system, but there is supposedly a way around it. And it's nothing to do with overcharging, but rather less drag on the motor when the alternator isn't charging, although it seems counter-intuitive since the alternator will be draggin double to charge it back up to 14v.

Edit: Found a TSB

Condition/Concern:
Some customers may comment that their voltmeter is fluctuating between 12 and 14 volts on their full size pickup / utility vehicle.

Recommendation/Instructions:
Starting with the 2005 model year, light duty full size pickups and utilities, are equipped with a new Regulated Voltage Control (RVC) system. This system turns off the alternator when it is not required in order to improve fuel economy. The alternator will turn back on when additional voltage is required. This will cause the voltmeter to fluctuate between 12 and 14 volts as opposed to non-regulated systems which usually maintain a more consistent reading of 14 volts. This fluctuation with the RVC system is normal system operation and NO repairs should be attempted.

 

[Thewes]

Something like this, although I didn't think it was supposed to drop that low, like maybe 12.Xv or something. Its a common thing with 05 up trucks I think, I can't remember what year they went to that system, but there is supposedly a way around it. And it's nothing to do with overcharging, but rather less drag on the motor when the alternator isn't charging, although it seems counter-intuitive since the alternator will be draggin double to charge it back up to 14v.

Edit: Found a TSB

Definitely can see that affecting my car audio system. Wonder if there is a way to disable it...

 

[Egghaus]

The RVC system is explained in the owners manual.