I use my C8 as a daily driver and won't be using it for about 3 weeks. Plan on leaving it unlocked so no additional drain on the battery and wondering
if anyone has had a problem with there battery running down in similar circumstance.
Thanks

 

You should be OK (I've done it) but it also depends on the health of the battery. The system goes to sleep and has low parasitic draw, it doesn't matter whether or not if it is locked. GM recommends to use a maintainer if the often sits for more than a week.

 

Get a Deltran Battery Tender !!

 

If you daily drive it you'll be fine.... I have 33 years in Corvettes and have never used a battery maintainer. Never a problem. Have had my cars sit 3, 4 weeks....

 

3 weeks is no issue.

 

Why wouldn't you just hook up a battery maintainer just to be safe?

 

I agree, cheap insurance. Also good to have when you do updates. When the car wants to do an update I plug in the tender first then shut down the car. I leave it on after the update over night just to be sure.

 

The "Getting to Know Your Corvette" guide that came with your car says use a battery tender if the car will be driven less than one week. I use a battery tender.
But your question was has anyone had a problem with there battery running down in similar circumstance. I have had other late model GM cars sit for 3 or so weeks and they have started without a jump. Don't recall ever having one with a good battery run down to the point of not started in three weeks.

 

With a good, healthy battery leaving it sit for 3 weeks should not be a prroblem. But, if it were mine, I would go ahead and hook the car up to a battery maintainer and not worry about it.

 

FWIW, have left my two C7s I've had for 8 years for 3 weeks several times and last October my 2 year old C8 with 2 year old battery for 3 weeks. All started just fine.

Both the C7 and C8 have battery power saving circuits that cut all significant power after ~10 minutes. Leave the Frunk (etc) hood open, look at the light and after <10 minutes it's off. This is a chart from the C7 that shows with an 80% battery charge how many days the car can start depending on the paracity battery current draw.

A member has measured the C8 after 10 minutes and the parasitic current draw is less than 15 milliamps. Your fine. No need to leave it unlocked as the current draw is no different, it's still looking for a FOB. BUT that is very low overall current draw.

SOFTWARE UPDATES:
BTW, for those that think by leaving their GM battery charger connected for a softwire update is a solution to the issue- may not be! The GM charger is only about ~4 amp capacity! Note in table at 2 amp current drain the battery will be at ~50% in less than a half day! The parasitic current measurements made showed soon after leaving the car the current draw was ~8 amps! It quickly reduced BUT just how much current is being used during a failed software update (that is when the batty has been dead as reported) if over 4 amps, it's not a guaranty safe "solution." So is an 8 amp current draw is twice the output of the GM charger at max. Using the table it will only take 2.4 hours to be at 50% charge. For those who's eyes roll with numbers, the GM charge is only putting out enough power to light a ~50 Watt bulb in your house!

I have done perhaps ~10 software updates on my 2020. Have never had an issue. BUT I usually accept when I'm in my garage connected to my WiFi. I check the car after ~1 hour or so to be sure it's OK. Has always been fine. I did have one early update that would not take after a number of tries. Brought it to the dealer and Tech took ~30 minutes connecting to my OBD and his PC via the dealer's WiFi to the GM computer. He said he occasionally has had that issue with other Chevy's. Took two tries but was finally installed. Because it was a 2020 may be something that was not a factor for later C8s.



With a C8 parasitic current drain of <15 milliamps your good for `40+days. I don't like to use my battery charger when I'm away as have many lightening storms late in day. But have used my GM equivalent CTEL charge before I leave for several weeks to be sure the battery is at 100% not just 80%. The car's charging system (like many modern cars) is controlled by computer and in most cases will only charge to 80%. This pic made from from the 4 volume service manual states days from 80% charge.

 

I always use a maintainer if more than a few days. My dealer recommends after 3 days, as they never know the battery condition and / or fully charged.

If in a secure location. Clearly. keep the key fob away from the car, like inside the car, if you don’t use a maintainer, as will cause more battery drain. Locking car, doesn’t reduce drain on battery.

Lastly, if you don’t use a maintainer, know how to
jump start, if necessary.

But maintainer is way to go. No drama.

 

Get yourself a battery maintainer, it's cheap insurance for peace of mind

 

If I don't use mine for a week or so I plug it up to the battery tender.

 

For all of those saying get a battery tender for easy insurance, sometimes cars are stored in a place without electricity...

I keep my C8 in a storage unit with no power. I have left it for over three weeks numerous times without issue. As some have said, it depends on the health of your battery. Last fall mine sat for 27 days and started fine. At that time the car was approximately 16 months old.