[Opus13]

This is why I joined. I recently notice the voltage gauge showing a little over 12 volts while driving. I'm old school, alternators run at 14 volts all the time. So I come here and find out that this is normal. This is a great forum.

[Mr. Wyndham]

I have been working with marine systems and giant 8D batteries for the last 7 years, and we've had to troubleshoot the charging system with DC/AC inverters, Alternators, and AC shore power...while I'm nowhere near an electrical engineer...I've learned a great deal about the characteristics of batteries, bulk, float, and maintenance charges...and false charge readings from recent charging.

I always thought it was neat, and efficient of modern automotive systems to have a smart charging system that doesn't keep pumping out 14.3-14.7 volts constantly like our boat does.

[camaro426@]

My 2011 Silverado also has the "only charge when needed" software. It's made to help gas milage and to NOT overcharge the battery. I freaked when I first saw the needle dip on the truck, then I found out why. '17 2SS does the same thing..........

[Giri]

Yeah, unfortunately. It does mean that I can't charge my DJI drone batteries unless the car decides that it's putting out enough voltage. Which never happens when I need it.

[fastball]

Adaptive charging has been standard in cars for a long time. Probably 20 years. Since the ECM became a vital part of engine operation so right around the time of OBDII, like 1996. You probably either never noticed it or your older cars didn’t have a volt meter on the dash.

[lt4camaro]

Originally Posted by eurostyle

A battery at 12.6 or 12.3 is a dead battery. Take a volt meter and measure right at the battery for accuracy. My 2 15 Camaros always showed charging between 13.4 and 13.8. This new 16 show charging of 12.4. Something is not right.

The older way always showed 13.8 to 14.2 when the car is running. This is telling you the alternator is charging at 13.8 to 14.2 volts. With the car shut off the reading will change as its telling you battery voltage now, not the charging rate of the alternator . The new cars have a smart charging system and while the car is running it will show anywhere from 12.5 to 14.3. You are correct by saying if the car is running constantly at 12.3, the battery will soon be weak as it is not charging , eventually seeing 12.0, 11.5 etc

[Camvette]

Such a great forum. See the exact same thing. Thanks for letting us know it's normal and explaining why!

[robbie52]

Car has been sitting for several weeks and decided to measure battery voltage under hood, since there are so many battery issues. Voltage read 12.08 volts and I was surprised that car started with no hesitation.

[craigss50]

I just replaced my OEM battery which was 4 years old because it always showed 14 V on the dash gauge and started to show 12.5 so I figured it was going bad. I put in a new glass matt battery and it is doing the same thing fluctuating between 12.5V to occasionally 14V. I called my dealer and he told me what GlenE posted. Newer systems are smart voltage regularors which don't charge until it's needed but what I don't understand is my OEM battery always showed 14V until about 4 weeks ago. Also my battery maintainer takes the voltage up to 14 and levels off. Is that actually hurting the battery?

[UnknownJinX]

Originally Posted by craigss50

I just replaced my OEM battery which was 4 years old because it always showed 14 V on the dash gauge and started to show 12.5 so I figured it was going bad. I put in a new glass matt battery and it is doing the same thing fluctuating between 12.5V to occasionally 14V. I called my dealer and he told me what GlenE posted. Newer systems are smart voltage regularors which don't charge until it's needed but what I don't understand is my OEM battery always showed 14V until about 4 weeks ago. Also my battery maintainer takes the voltage up to 14 and levels off. Is that actually hurting the battery?

Just means you have enough electrical load to have the alternator run at a higher voltage at all times.

If you are using a maintainer dedicated to AGM batteries, you should be okay.

Sent from toaster or something

[Rayvan]

Originally Posted by Giri

Yeah, unfortunately. It does mean that I can't charge my DJI drone batteries unless the car decides that it's putting out enough voltage. Which never happens when I need it.

You can add a new 12V port in the trunk, directly to the battery so you can charge stuff without the key. I've done this to all my cars. Find them on Amazon, or in camping stores...

[ChrisM]

Hi , New to the group. have a 2016 2SS that intermittently will not start mostly after small stops and starts. Change the battery, and still got stuck. drive for a bit , shut it off wait for a few then try to start if there is no juice. get the message the battery is low. Took it to the Dealer (to see if under warranty ultimately it wasn't) and they found a cable (negative I believe was dropping 1 volt which is too much. They changed the whole harness. Took the car on a drive, shut if off 15 mines later, it was dead again. It's not the starter getting heat soaked, I added another ground as mentioned in another post. Other times the car is fine. Did notice that its voltage gauge is dropping to 12.5 (ish volts) while we say this is normal, mine seems to stay n that range for a long while and that is not normal. Let it run for 2 hrs like this and the car died! Checking the BCM and ECM to make sure commands are working to turn on and off the alternator when it s supposed to but it's hard when the problem is intermittent. GM opened a tech case on this. Luckily I have a brother is who is super tech at GM and he is the one doing all the leg work on this. So far no culprit found yet but there are theories. I will share once we have an answer/solution. Frustrating to keep getting stuck after spending about a 1,000 bucks.

[arpad_m]

Originally Posted by ChrisM

Hi , New to the group. have a 2016 2SS that intermittently will not start mostly after small stops and starts. Change the battery, and still got stuck. drive for a bit , shut it off wait for a few then try to start if there is no juice. get the message the battery is low. Took it to the Dealer (to see if under warranty ultimately it wasn't) and they found a cable (negative I believe was dropping 1 volt which is too much. They changed the whole harness. Took the car on a drive, shut if off 15 mines later, it was dead again. It's not the starter getting heat soaked, I added another ground as mentioned in another post. Other times the car is fine. Did notice that its voltage gauge is dropping to 12.5 (ish volts) while we say this is normal, mine seems to stay n that range for a long while and that is not normal. Let it run for 2 hrs like this and the car died! Checking the BCM and ECM to make sure commands are working to turn on and off the alternator when it s supposed to but it's hard when the problem is intermittent. GM opened a tech case on this. Luckily I have a brother is who is super tech at GM and he is the one doing all the leg work on this. So far no culprit found yet but there are theories. I will share once we have an answer/solution. Frustrating to keep getting stuck after spending about a 1,000 bucks.

That sucks, and I have no other advice than the avenues you're already tried, except maybe checking for persistent parasitic loads. Please keep us posted.

[cengell]

Hi all after looking here i'm sure I have an issue. 2 weeks ago when it was about 35 degrees I let my car sit for 10-14 days and then started it and went somewhere about 100 miles round trip and saw the digital dash voltage was 14v - 14.2v, I plugged in my cigarette lighter voltage meter and it was mostly charging in the 14v-14.2 and understand that with the cold and car sitting this could be normal?

I replaced the original GM Delco battery about 4 months ago from Walmart with the same ratings and so, that next weekend I put my AGM charger on and it was fully charged by the next Monday. So this weekend I connected it and was fully charged from this past Sunday and this morning Monday I drove 50 miles and really did not pay attention to the charging meter, and on my return trip I'm see that gauge read about 11.5 volts. Then plugged in my lighter volt meter and the voltage was 11.5 lowest to 14 and seamed like there is a power charging issue or a AGM cell issue?

When I got home today I connected my OBD2 reader and it has a battery good or bad test and it was good, then I tested the Alt system and it was also good.

Since 2017 I don't ever recall my charging voltage ever was around or less then 12 ish volts!

I will tomorrow after my car sits over night and measure the battery voltage and I bet it will be under 12v. So I am thinking it's either the somewhat new battery or it's the Alternator charging/ charging circuit? So 3 possible parts?

Any suggestions other than drive to an Autozone and I think they will use there OBD2 unit like I did that shows Good? I don't want to remove the battery as it's a pain to get to but I can also after I see what the resting battery voltage is put my AGM 10 a charger and later that day remove and measure the battery voltage and then again later that night to see if the battery is holding?

Or I have 2 of the 3 parts the issue... Just odd and any help welcomed!!

Thanks
Christopher

P.S Also I am not getting any low voltage warnings from the car???