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Discussion Starter · #1 ·
Coming up on 2000 miles on the new 6.6 gasser. I very rarely see the volt gauge drop below 15V. I have confirmed this with DVM at the battery (15.05V).
Is this typical? Anyone have the parameters truck looks at to determine charging voltage? I have seen it vary a little lower and even dropped below 14V once that I saw. Lot higher voltages than my '17 5.3L. Just wonder if I should mention to dealer or not if it goes in.

I do have the aux battery and 220 alternator.

Thanks
 

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Voltmeter Fluctuation Condition per GM
"Some customers may comment that the voltmeter is fluctuating between 12 and 14 volts on their full size pickup or utility vehicle. Starting with the 2005 model year, light duty full size pickups and utilities are equipped with a Regulated Voltage Control (RVC) system. This system reduces the targeted output of the generator to 12.6-13.1 volts when in "Fuel Economy Mode" to improve fuel economy. The generator may exit "Fuel Economy Mode" if additional voltage is required. This will cause the voltmeter to fluctuate between 12 and 14 volts as opposed to non-regulated systems that 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".

My gauge reads slightly above 14v often and has done it for as long as I have owned the truck. I have an aftermarket stereo with amps so a high reading often makes sense in my case. It will read lower at times, but I am bangin the sub often so it stays high. I have seen it lower than 14v with the sub playing now and then though. I think you are okay.
 

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2015 Silverado LT Texas Edition
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Here's the info right out of your owner's manual:

Battery Load Management The vehicle has Electric Power Management (EPM) that estimates the battery's temperature and state of charge. It then adjusts the voltage for best performance and extended life of the battery.When the battery's state of charge is low, the voltage is raised slightly to quickly bring the charge back up.When the state of charge is high,the voltage is lowered slightly to prevent overcharging. If the vehicle has a voltmeter gauge or a voltage display on the Driver Information Center (DIC), you may see the voltage move up or down. This is normal. If there is a problem, an alert will be displayed.The battery can be discharged at idle if the electrical loads are very high. This is true for all vehicles.This is because the generator(alternator) may not be spinning fast enough at idle to produce all of the power needed for very high electrical loads.A high electrical load occurs when several of the following are on, such as: headlamps, high beams, fog lamps, rear window defogger,climate control fan at high speed,heated seats, engine cooling fans,trailer loads, and loads plugged into accessory power outlets.EPM works to prevent excessive discharge of the battery. It does this by balancing the generator's output and the vehicle's electrical needs.It can increase engine idle speed to generate more power whenever needed. It can temporarily reduce the power demands of some accessories
 

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Discussion Starter · #4 ·
Thanks. I knew about the load management and varying charging voltage from my '17 5.3L. I have just noticed that this new truck doesn't seem to drop the voltage nearly as much/often. I'm mostly curious if a near constant 15+ V is too much and should be looked at. I would think (maybe old thinking) that high 13s or low 14s under normal conditions with occasional drop for fuel savings. That is what I was used to with the Silverado.
Like I mentioned, I have seen it drop below 14 a couple times so something is working. Just seems to spend 95+% of the time at 15V.
 

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2015 Silverado LT Texas Edition
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Have you checked gauge accuracy?
 

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Discussion Starter · #6 ·
No lines on dash gauge, but seems to agree with my DVM. DVM reads 15.05V at idle when the dash gauge is sitting at the popular spot, which looks to be about 15V.
 

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roorancher said:
Here's the info right out of your owner's manual:

Battery Load Management The vehicle has Electric Power Management (EPM) that estimates the battery's temperature and state of charge. It then adjusts the voltage for best performance and extended life of the battery.When the battery's state of charge is low, the voltage is raised slightly to quickly bring the charge back up.When the state of charge is high,the voltage is lowered slightly to prevent overcharging. If the vehicle has a voltmeter gauge or a voltage display on the Driver Information Center (DIC), you may see the voltage move up or down. This is normal. If there is a problem, an alert will be displayed.The battery can be discharged at idle if the electrical loads are very high. This is true for all vehicles.This is because the generator(alternator) may not be spinning fast enough at idle to produce all of the power needed for very high electrical loads.A high electrical load occurs when several of the following are on, such as: headlamps, high beams, fog lamps, rear window defogger,climate control fan at high speed,heated seats, engine cooling fans,trailer loads, and loads plugged into accessory power outlets.EPM works to prevent excessive discharge of the battery. It does this by balancing the generator's output and the vehicle's electrical needs.It can increase engine idle speed to generate more power whenever needed. It can temporarily reduce the power demands of some accessories
Curious if my 2014 has the EPM system you describe ... what year was it introduced?
 

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Rambodog said:
Voltmeter Fluctuation Condition per GM
"Some customers may comment that the voltmeter is fluctuating between 12 and 14 volts on their full size pickup or utility vehicle. Starting with the 2005 model year, light duty full size pickups and utilities are equipped with a Regulated Voltage Control (RVC) system. This system reduces the targeted output of the generator to 12.6-13.1 volts when in "Fuel Economy Mode" to improve fuel economy. The generator may exit "Fuel Economy Mode" if additional voltage is required. This will cause the voltmeter to fluctuate between 12 and 14 volts as opposed to non-regulated systems that 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".

My gauge reads slightly above 14v often and has done it for as long as I have owned the truck. I have an aftermarket stereo with amps so a high reading often makes sense in my case. It will read lower at times, but I am bangin the sub often so it stays high. I have seen it lower than 14v with the sub playing now and then though. I think you are okay.
Thanks for the info on how this works ... new to me 1500 was running typically at 14v (what I've be used to with other cars) driving around town, but dropped to near 12 v on long highway trip and thought it was broke! Thx for saving me a Bill!
 

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TractorMan said:
Curious if my 2014 has the EPM system you describe ... what year was it introduced?
GM has been using this system since 2005.
 
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