geewez

Just got home from attending the Spring Mountain course and went to Vegas after words. I was keeping an eye on the gauges of my 2017 Grand Sport and noticed the digital volt gage showed just 12.8 volts pretty much all the time. I've always thought that the electrical system should be putting out between 13.5 to 14 volts while the car is running. Just curious what everyone is seeing for voltage on a running car. The digital gauge was a steady 12.8 volts and only a couple of times did I see it show higher voltage. If this is too low as compared to everyone else's display I'm going to take it in to have the alternator and/or battery replaced before my warranty expires in a couple of months.

Bubbletop409

I'm guessing you were probably running your AC near the max most of the way and the stereo and amp may take a bit of voltage. A simple volt meter test with all your electrical turned off will probably show a slightly higher reading, I wouldn't worry at this point.

ScottMA64

Mine always varies. I've seen 12.8 while driving and all the other voltages as well. Seems pretty normal to me.

S

cowboy casey

14.2>8 when started from sitting overnight

12.8 when cruising more than 20 miles as the battery is charged and basically the vehicle is keeping the battery in float charge

Dcasole

The ECM controls the alternator now and reduces charge when it's not needed , i am sure this was put in place to increase MPG and to try an extend battery life from not overcharging all the time , before replacing my battery I would routinely see 14.4 to 14.8 all the time , when I put a new battery in that is oversized (920 Amps 760 cca ) I only see 14 volts or higher if i have just started it or i have a lot of load on the battery , most of the time i see 12.8 during normal driving

Dave

vader86

Its smart charging, the computer controls how much voltage is across the battery.

DAC17

Once warmed up, 12.8 is just about my average reading.

NSC5

GM gasoline powered vehicles have used ECM controlled alternators for a couple of decades now. The control program is designed to optimize fuel economy and also to optimize battery life varying charge level as temperature varies. At times you will see the system voltage reading drop below nominal unloaded battery readings as alternator output is dropped while the battery is still under load and at other times it will be in the 15 volt range when a high charge rate is commanded. The system can also drop high current accessory items if the current level of battery charge and available alternator output require power to be conserved. It is not unusual or abnormal for the voltage to vary rapidly as the system controls alternator output based upon operating parameters.

The only real annoyance with this system is evident with HID headlights but vehicles using this system and traditional tungsten/halogen bulbs will show definite changes in illumination as the system voltage is commanded to different levels. I owned a 2001 Olds Aurora and the early generation of this controlled charging system lacked in refinement and was annoying at night when it would radically change output level and resulting system voltage. But even current GM vehicles with older style headlamps are not that bad with the more refined algorithm used now.

mschuyler

I'd say 12.8 is normal on a road trip. Starts out a bit higher for a few miles, but usually calms down to 12.8 once it gets up to snuff. Working as advertised. Temperatures worry me sometimes, but not voltage.

Mike's Sweet 19

Where do you have the voltage displayed.
I have a 2019 that I run in Sport mode and I do not have a display that shows a voltage read out. Is the display for voltage selectible from the menu.
I have a 1LT trim on a Z51 Stingray.

Thanks.

KenHorse

On the DIC, under the Perf (Performance) selection

Red08

My Silverado did the same thing, I stopped at a Chevy dealer and was told that it charges more when its needed. He said the variance is normal.

subieworx

How many times can the same statement be repeated?

Mike's Sweet 19

Thanks for the information.
I went back to the manual and found that section that explained the DIC. Somehow I missed it in the first read.