[drperry]

Originally Posted by 17rsvert

Update. My dash voltage reads 12.1 volts most of the time when driving, which concerns me because my battery is not staying fully charged. I had the battery hooked up to my Schumacher smart charger every night overnight last week. The car sat unused without the charger over the weekend, and when I checked the voltage (Fluke multimeter) Sunday night it was 12.52. The next day (without using it or even opening a door) it was down to 12.41 volts. The next day I drove to work and back 1/2 hour each way, and when I got home, checked the voltage again with the car shut off and it was 12.25 volts. That night I charged the battery again overnight and disconnected it in the morning. Car sat unused all day, I drove my beater jeep to work. When I got home the battery read 12.85 volts. This does not make sense.

The car has a computer controlled charge cycle... It should bump up the charging with the headlights and A/C on... The battery may be hooped, though... Hard to tell... It shouldn't go dead after a week.

Sent from my SM-G930W8 using Tapatalk

[16BlueSS]

17rsvert

I feel your pain. I went through this last year at this time and it took 5 mouths for GM to sort it out. They sent a Tech from Detroit and he found it on day two of trouble shooting.
It was a problem with the passenger side seat motor and controller. For no reason it would spike a current draw that would pull the battery all the way down. Mine has been fixed for 8 months now and never another problem.
There should be a GM tech document as that was part of what the the GM tech was supposed to do.

Best of luck
CD

[17rsvert]

Update. Charged battery for 4 days straight with ground wire to car disconnected. Checked voltage daily after charger off with ground wire still off. Measured 12.93 v after one day, and 12.68 after a week. I assume thus means the battery is not the problem?
Next, put the car in transport mode and charged the battery again to full. Day after charger removed measured 12.65, next days were 12.54, 12.42, 12.36 and today 12.25. Not good, Transport mode does not stop the bleeding. Without further charging, just took a 2 hour highway ride and watched if the volt meter in the car would show how the 'smart' charging system would recharge a somewhat discharged battery.
Was dissappointed to see that during the entire 2 hour ride, the voltmeter showed 12.1 to 12.2 volts, only going above 13 volts for a few seconds several times.
WTF? I may not be as smart as the "smart" charging system, but I can't see how the system could possibly take a battery reading 12.25 volts and charge it to a full 12.65 volts if it keeps the system voltage at 12.1 or 12.2.

Am I missing something here or is this a faulty set-up in the electronics?

[avalonandl]

The smart charging is keeping it above 12v. I would say its ok at this point.

[17rsvert]

Originally Posted by avalonandl

The smart charging is keeping it above 12v. I would say its ok at this point.

By most estimates I see, a battery at 12.1 volts is a 50% discharged battery. How can that be OK? A fully charged and rested battery reads 12.6 to 12.7 volts. A charging system that "is keeping it above 12v" without going up above 12.7 is never going to fully charge a battery.

Say your tire pressure is supposed to be 35 psi. You have a tire with a slow leak, and that tire actually at 25 psi. You will never be able to fill that tire if the compressed air supply is only at 30 psi max. In fact, if that same tire was full at 35 psi and you suppled it with 30 psi air, the tire would deflate to 30. You would need supply air of at least 35 or 36 psi to fill the tire, and reaching that last pound/square inch would be very slow.

[matt fe2o3]

Originally Posted by 17rsvert

By most estimates I see, a battery at 12.1 volts is a 50% discharged battery. How can that be OK? A fully charged and rested battery reads 12.6 to 12.7 volts. A charging system that "is keeping it above 12v" without going up above 12.7 is never going to fully charge a battery.

Say your tire pressure is supposed to be 35 psi. You have a tire with a slow leak, and that tire actually at 25 psi. You will never be able to fill that tire if the compressed air supply is only at 30 psi max. In fact, if that same tire was full at 35 psi and you suppled it with 30 psi air, the tire would deflate to 30. You would need supply air of at least 35 or 36 psi to fill the tire, and reaching that last pound/square inch would be very slow.

I don't think you are apples to apples. The charging system runs the car as it operates, not the battery. With lights on auto - in daylight the car's power generation system may well only need 12.1 to function. The battery is the storage system and outside of (via diodes and circuits) of what the charging system reports on dash.

What I suggest is you get a decent fluke out and test fuse circuits. It's a little slow to do - however you should be able to identify each circuit that has a draw when off and measure it.

There's a bunch of tools on youtube.

This guys has some basics. https://youtu.be/KF1gijj03_0

One thing to remember - he does not mention it (that I noticed) is be aware if your hood and/or trunk is open - there are things/circuits in modern cars that might still draw current, lights, door or trunk ajar, etc. So don't stop at any fuse - do them all and keep a record of each fuse circuit that show's a draw.

Then you back-fill your investigating by looking to each circuit that has a draw and review consumers on each end. All this can be done without without a wiring diagram - but at some point you will need to understand what consumers are on each circuit that you want to investigate.

DO pay attention to the safety stuff. I would say a few hours WITHOUT beer will give you an idea of where your issue may be.

Edit - he does mention keeping FOBs away and auto updates that happen - so just be aware.

[17rsvert]

Update.
Drove the car 3 hours mostly highway then home on Sunday night. Checked the voltage Monday morning, 11.45 volts. Let it go without the charger again overnight to see what would happen and this morning, 5.52 volts.
Looks like it's back to the dealer, and they better not tell me that the battery tests good, the parasitic drain is below spec and there is nothing wrong with the charging system.

[GrimReaperSS]

Sounds to me like the battery itself is internally discharging/shorting. While discharging is natural for every battery due to the materials inside, the excessive amount you're seeing is definitely not. A batttery that is that low in voltage tells me that there is a problem w/ one or more cells. You also cannot perform a parasitic/dark/quiescent (what ever term you like to use) current draw test w/o a healthy battery. In general, 20 to 60 mA (.020-.060 A) draw is what's acceptable to most brands. I dont know the charging systems on the new Camaro's, but a lot of new cars do have a "smart" system like mentioned above. With the car running at idle, you won't see a voltage increase from the alternator, for quite some time. This can mess with a lot of techs that arent aware of how the new systems work. They'll do a charging system test, like you would on an older system, see theres no voltage change and condemn an alternator. The system works this way to only be used as needed, so as to keep the load on the engine at a minimum to promote better fuel economy.

[GrimReaperSS]

From what I can find of GM's specs, you're looking for less than 30 mA of draw, although depending on which systems could be equipped, there could be spikes up to 40, 50, 80 or 100 mA. The systems typically take up to 30 minutes to go to sleep but can take up to 2 hours.

[GrimReaperSS]

Hope these help you understand how they view current draw.

[Glen e]

You will never convince me that this car in some way , shape or form does not have a engineering, parts or design defect that causes the battery sometimes to just go flat. I went to two different dealership, replaced the battery once, and still it would sometimes without reason take the battery flat in three days. Other times it would last five weeks. I finally got so sick of it that I mounted a battery switch that would disconnect my negative and anytime the car was going to sit for longer than two days And eventually I sold the car. the dealers that looked at this car were competant and could find nothing wrong.

This is not a new problem. We've been dealing with this here since 2016. Do a search here you'll find all sorts of early posts of the six Gen that experienced this problem.

[GrimReaperSS]

Glen e: Im not saying there isnt. Just trying to provide some insight on how the testing is performed and what specifications have to be met. Helps sometimes to see what the tech has to do on their end, you know, two sides to every story kind of thing.

[GrimReaperSS]

Charging system

[GrimReaperSS]

Battery