So I have a 2021 C8 and have had to replace the battery now a 3rd time in about 15k miles.

Basically it keeps getting completely drained by something. Is anyone familiar with this? I'm not too keen on paying 200-300$ every few months to buy a new battery. Unfortunately I am unable to keep it on a tender since I park it in the driveway and nowhere to plug it in.

I have been reading about the OTA updates and how they have been a big problem with battery life. Is there any way I can disable these myself? I would rather not get any updates since I dont use any of the applications anyway, I just drive the car.

Any assistance would be greatly appreciated. Super annoying. I can tell the battery is starting to go when I hit the start button on the car, everything turns on, but it fails to crank over and I need to disconnect the negative terminal from the battery in order to get the car to even shut off.

Love the car, just have had a ton of problems always due to the battery.

 

Have you recharged the "bad" batteries and had them tested? It is quite possible that they weren't bad although it sounds like something is wrong with your car it shouldn't do that. If you only take short drives or let the car sit more than a week without driving it can cause the battery to get low but people have left their cars undriven for weeks and had no problems starting it. If you don't drive it often and can't get a maintainer to it you could disconnect the battery while the car sits. Also, the batteries are covered by the 3 year bumper to bumper warranty so you shouldn't have been paying for them but you have to get your car to the dealer so they can verify the battery is the problem.

You can disable downloading of the updates in the background in the settings but the car will never install the updates without your permission. People that have dead batteries due to updates had the battery go dead after they accepted the request to install the update.

 

An OTA update won't take place without your consent, so unless you've approved updates just before the battery died that's not the issue.

Batteries come with warranties - if it dies prematurely you should get a least part of the purchase price back. When one dies, have you hooked it up to a charger (even if you have to take it out of the car) and see if it lasts for another 2 or 3 months? Even if something drains it, a charge should bring it back. You may need a regular charger, not a battery tender, to bring back a completely dead battery.

Where do you live (how hot is it there)? How often do you drive the car as opposed to it sitting in the driveway? Heat is a battery killer, and disuse is hard on batteries. If the car is driven infrequently, can you run an extension cord into the garage and at least put a battery tender on it once every week or two?

I would have the charging system checked out by a competent shop. There may be an issue there. If that checks out OK, ask them to check the current draw when the car is idle, starting after 10 minutes post shutdown. If it's dying in just a few months, I have to think one of the above is likely a problem.

This is not a common issue. Other than the relatively few (compared to the number of C8s sold) cars that had the battery drain after OTAs, the battery and charging system hasn't been an issue. Mine is almost 2 1/2 years old, is almost never on a battery tender, and the original battery is still going strong. I know of one owner with a 2020 on the original battery (probably plenty of others, but this one I know for sure).

 

Get the dealer to check the parasitic draw in addition to what was suggested above. Or, if you have a low currrent clampmeter, you could check it yourself. I measured it and posted some results here
https://www.corvetteforum.com/forums...e-battery.html
After the car has been sitting off and undisturbed for around 15 min (and I moved the key fob away) it drops to around 10-11 ma (which is small).

 

https://www.batterytender.com/12v-5w...rger-handlebar

Battery Tender® 12V, 5W Mountable Solar Battery Charger

 

Do you have anything connected like an ipod, radar detector, etc? This could be an issue.

 

Thanks for all the feedback everyone. My guess is parasitic draw as well, but no idea why. I dont really use anything aside from driving the car. Also so last time I had a guy from AAA come when it died, he tried to charge it but it was completely dead. This time I ordered a jump starter off amazon and it at least gets the car and the electronics to turn but, but seems to not be giving enough charge for it to crank. It sounds like it wants to, but just stops. Hoping I can get it charged enough to take it the dealer, since I'd rather not have it towed.

I am going to disable the OTA updates anyway just in case as an extra measure.

One thing though is I really dont drive much. Maybe 5-10 miles a day, three days a week. Possibly one bigger trip on the weekend but at most 30 miles each way.

That solar powered battery tender is exactly what I needed, so going to order that today. That solves the problem of having to plug one in. Great reply!

 

No way you should be going through that many batteries in such a short time. Something is not right with your car's electronics IMO.

 

Agree, either larger then normal parasitic draw, or charging system issue. The dealer has procedures in the Service Manual to test both. The parasitic draw procedure in the 2020 manual that I have is named Battery Electrical Drain/Parasitic Load Test. Also, that 5 watt solar charger will produce - 0.416 amps which is less than one tenth what the Corvette supplied battery maintainer can produce (4.3 amps) - and then it will only produce that in sunlight. It might keep up with a normal parasitic draw of 10 ma, but not much more than that.

Although the Getting to Know Your Corvette guide included in the owners packet says "If the vehicle is not driven weekly, or the battery is disconnected or drained, use the optional battery maintainer to charge the battery", folks have reported going much longer and still being able to start the car (I wouldn't do that, but many do). OP reports driving "Maybe 5-10 miles a day, three days a week".

 

That should be enough to keep a reasonable state of charge on the battery. Definitely something else going on.

The battery tender may help mask the problem, but it's a bandaid, not a fix.

 

Is this your first Corvette because they've been having similar battery "issues" since at least the C6, if not longer.

 

Really? I’ve owned one of every generation since the C4 and the C8 is the first that I keep on a battery maintainer. Zero issues with batteries in my C4, C5, C6, or C7.

 

You need to do as Andybump says and check for draw, it could be a stuck relay. Other than OTAs going off the rails and killing a battery, most have been fine. These cars are quite voltage sensitive and will go from zero crank to roaring to life like it's got a fully charged battery. I personally saw one go through three jump packs and nothing to one more attempt and it started like normal (I.E. no slow moaning crank, just fired up now).

 

Hogwash. Of the 150 or so people in my Corvette club, I've never heard one complain about battery issues.

 

My guess is the charging system is not working. Take the car to dealership service.

 

Use a solar panel with an OBD to cigarette adapter. Even a small panel should give you some extra charge to compensate for drain.

 

Battery drain has been a huge topic since the C5's at least. The discussion of maintainers is commonplace. These cars definitely have uncommanded (by the owner) draws happening and are well-known for this.

 

Don't be fooled. One day the car starts fine, the next day it's dead. I've had that happen on other cars. If you get almost 3 years on an OEM battery, you are on borrowed time. I'm right there with you.

 

Always do the simple thing first.....get a long extension cord and keep it on the tender

 

I thought I would be smart and replace my 2020 battery at 3 years. I got an AGM battery and it died in a year. Luckily it was in my garage. II was just about to go 2 hours from home. It was replaced for free and the replacement looks like it will be fine. You never know about batteries. The original battery is doing well in my other car.