Last week, after washing my '20 coupe, I attempted to start the car, but it acted as though the battery was dead (dash gauges flashing, etc), then I recalled it had acted weird when I started it to move it from the garage. It acted normally the day before when driving around town. I put the charger on it and got it running later that day. I was under the impression the battery was on it's way out, as it's four years old and living in Arizona, so I purchased a new battery, though the battery, after charging showed to have 12 volts on the voltmeter. Purchased and installed a new battery and all seemed ok till this morning, when I found it to be completely dead. Had to access the car manually. (I drove the car 4 or 5 time after installing the new battery). It sat for only 2 days since last drive. I don't have the gauge cluster configured to show battery condition, so can't be sure whether it stopped charging or now have some other electrical/electronic problem. The battery is at only 4.5v.

I haven't found any similar threads by searching here, though I could be missing similar issues.

 

Sounds like there is a parasitic draw going on. Get yourself a voltmeter and make sure the battery is getting charged by the alternator. Should be seeing 14-15 volts at battery when car is running.

 

defective battery or parasitic draw or charging system failure.

Here is a discussion of measuring parasitic draw. I assume a dealer could do this. But, you have to wait 10-15 minutes for the car electrical system to fully shut down - so there is some labor time involved.
https://www.corvetteforum.com/forums...e-battery.html

The clamp meter I used was about 200 dollars. It needs to be capable of measuring very low currents (1 ma) - the parasitic draw I measured was about 10 ma. And it must be a DC ammeter. The clamp style will fit right around the battery cable and will measure DC current in or out of the battery accurate to a ma.

 

Dave64, did you ever sort out the root cause? I have seen a few threads with slightly different symptoms on batteries going dead and then new ones not lasting more than a few days to few months.

I went out of town for the july 4th week. When I came back after leaving the car undriven for 7 days, the battery was dead. I put it on a charger and after a few hours it seemed to stop charging. I tried to start the car, it would turn on but not start, or even crank. After 24 hours of trying to get the battery charged I decided to replace it. I have had the new battery in and car starts and drives fine, but now I have a check engine light on. I was planning to drive to a customer site tomorrow for work, but it has me nervous. It's 130 miles one way and fairly remote.

I made an appointment with the dealer for Thursday, but may try to change it to tomorrow and see what is going on, but I am curious if you sorted yours out.

Note: my car is a 2024 so the battery is only a year old.

 

Replacement of your battery should be covered under the 3/36 Bumper-to-Bumper warranty. You can download and read the warranty manual here:

https://contentdelivery.ext.gm.com/c...25JAN06_3P.pdf

The warranty covers everything unless it is specifically excluded in the what is not covered section. There is a list of maintenance items in that list that are not covered, but the 12 volt starting battery is not one of them.

 

Thanks! I had to replace the battery to avoid being stranded, but I will fight for reimbursement tomorrow. I topped up the fuel today and that fixed the check engine light, but still planning to take it tomorrow to make sure nothing else is going on.

 

Yes, I understand that (about needing to replace it). And right, they should check for excessive parasitic draw. After the car has sat off, undisturbed for 15 minutes or so, all of the systems have "shut down" and the parasitic draw that I measured on my 2021 dropped to about 10 ma which is actually quite low. It should not have run down in a week or two - unless the battery was defective or unless there was more draw than normal.

The warranty manual appears to address, to a certain extent, repairs that were not made by a dealer. Below is the relevant clip for a 2023 Warranty Manual.

"Maintenance and Repairs
Maintenance and repairs can be performed
by any qualified service outlet; however,
warranty repairs must be performed by
an authorized dealer except in a situation
where the vehicle owner is significantly
inconvenienced and a warranted part or
a warranty station is not reasonably available
to the vehicle owner.
In a situation where the vehicle owner
is significantly inconvenienced, and an
authorized dealer is not reasonably available,
repairs may be performed at any available
service establishment or by the owner, using
any replacement part. General Motors will incurred, including diagnosis, not to exceed
the manufacturer's suggested retail price
for all warranted parts replaced and
labor charges based on General Motors's
recommended time allowance for the
warranty repair and the geographically
appropriate labor rate. A part not being
available within 10 days or a repair
not being completed within 30 days
constitutes a significant inconvenience.
Retain receipts and failed parts in order to
receive compensation for warranty repairs
reimbursable due to these situations.
If you are in a situation where you
are significantly inconvenienced, and it is
necessary to have repairs performed by
other than a General Motors dealer and you
believe the repairs are covered by emission
warranties, take the replaced parts and
your receipt to a General Motors dealer for
reimbursement consideration. This applies to
both the Federal Emission Defect Warranty
and Federal Emission Performance Warranty."

 

Weather mode will show you volts

 

yes and no. I've been don't a lot of research because I've had this issue on my 2022 Stingray and data shows that even during driving, the alternator output voltage can, and will, drop to 12.6v for fuel saving and not to obey charge the battery. I was so focused on the voltage that it was having me pull my hair out but it turns out it's ok. Even the GM battery folks say the same thing. FWIW.