Voltage on dash reading low

Scboater · June 25, 2021

Battery was acting bad, and volts were reading 14 on dash and at battery. So I figured it had to be the battery. Changed the battery yesterday and stopped and started 5 or 6 times as well. I’m kind of a gauge watcher as well. So I jump in today and am heading down the road and look at the gauges and the voltage gauge is reading around what I guess would be 12 or so, and stays that way until I get to where I’m going. I’m thinking it may just need a reset. I stop the truck and let it sit a minute and then restart it. The gauges do their normal thing, they go to 3 o’clock and back to 9 o’clock and then settle to wherever. When I crank it up the voltage will read 14 like always for a minute or two and then it will drop to 12 or so. Took it to advance and they said it all checks out fine. I’m not comfortable with this. It was reading normal 14 yesterday after new battery was installed. Have y’all gurus seen or heard about this before? Any help is greatly appreciated.

Grumpy Bear · June 25, 2021

25 minutes ago, Scboater said:

Battery was acting bad, and volts were reading 14 on dash and at battery. So I figured it had to be the battery. Changed the battery yesterday and stopped and started 5 or 6 times as well. I’m kind of a gauge watcher as well. So I jump in today and am heading down the road and look at the gauges and the voltage gauge is reading around what I guess would be 12 or so, and stays that way until I get to where I’m going. I’m thinking it may just need a reset. I stop the truck and let it sit a minute and then restart it. The gauges do their normal thing, they go to 3 o’clock and back to 9 o’clock and then settle to wherever. When I crank it up the voltage will read 14 like always for a minute or two and then it will drop to 12 or so. Took it to advance and they said it all checks out fine. I’m not comfortable with this. It was reading normal 14 yesterday after new battery was installed. Have y’all gurus seen or heard about this before? Any help is greatly appreciated.

These are smart charging systems. What you are seeing really is normal. Be happy. Don't worry.

Phantom 4D · June 25, 2021

Yep. Threw me on my 17 Silverado when I had it. As mentioned, GM uses a variable voltage alternator, or smart alternator. Main reason is to keep the battery from overcharging and longer battery life.

Scboater · June 25, 2021

What’s weird is, why has it never done this before in the 4 years I’ve owned the truck? I’m gonna trust all the other replies on this same question and roll with it. Can’t wait for it to get dark out so I can test the theory that it should come back up once I get all the lights going. Will update if I do in fact end up with an issue.

Grumpy Bear · June 26, 2021

On 6/25/2021 at 4:59 PM, Scboater said:

What’s weird is, why has it never done this before in the 4 years I’ve owned the truck? I’m gonna trust all the other replies on this same question and roll with it. Can’t wait for it to get dark out so I can test the theory that it should come back up once I get all the lights going. Will update if I do in fact end up with an issue.

I had my truck a few years before I noticed the oil pump self test three cycles of the high stage side on each key cycle a few minutes after start up. Thought the pump was going south. :rolleyes: I'm a gauge hawk too and still missed it.