I'd unplug it. I've never left my 240v plugged in.

 

I've never left my 240v plugged in.

On the other hand… it’s not doing anything unless the car needs it so there is zero reason to unplug unless you want to move the car further away from something. If its at hilltop/target mode, it’s done and doing nothing. If it’s frigid, it stays warm. If it’s hot as balls out, it stays cool. EVSEs aren’t causing these fires.

 

I plug mine in when I get home and leave that way until I depart the following day. However, I have the car set so that it completes charging by the time I leave in the morning. That typically means that it starts charging about 2 hours before I leave. Right now, I’m using the level 1 charger so I can extend the cable outside under the garage door instead of the level 2 charger.

 

The guidance states move outside away from structures when done charging if forced to charge inside, which automatically implies unplugging it. Monitor it during charging which again implies not leaving it plugged in. It says nothing about leaving it plugged in after charging is okay or not. Or how long can it sit outside after charging can you move it back inside. Their guidelines suck but written by lawyers. 1000 people on the Internet will have 1001 opinions. We're all left to balance our own risk and roll the dice.

 

It probably does not matter much if the car is charged to your desired target charge level. Of course, if charging requires parking too close to buildings or other flammables, then you may have to unplug to move the car away from the buildings or other flammables.

However, if you have a 2017-2018 and want to charge it to a level lower than 88% (hilltop reserve), then you need to unplug it when it gets to your desired charge level.

 

Leaving it plugged in is (was) especially worthwhile on very hot or cold days, to help with battery and cabin conditioning. On moderate days, I don't bother.

 

Ours has been garaged every night, plugged in to an L2 charger set to Hilltop Reserve, for four-and-a-half years now. So far, so good.

jack vines

 

I use a Level 2 charger and charge my 2017 in the driveway. Sometimes I go to sleep with it plugged in and it typically finishes charging hours before I wake up. I unplug shortly after waking and only charge when it's down to 100 miles of range. But more often I get the "Your Bolt has finished charging" message before bed and I'll unplug it. Hasn't seemed to matter either way, yet.

I do keep a package of organic all-beef hot dogs in the freezer and I have some extra long skewers, you know, just in case...

 

It is still quite unknown as to the full picture on this.
You should read the current GM advice and use your best judgment.
Keep charge up often.
Don't charge more than 90%.
Don't let charge fall below 70 miles.
I'll add this. If you must charge in a structure then actively monitor it.
When it is finished charging, pull the car out of the structure.

What isn't said is:
Why DC charges are not doing this.
Why it seems to suggest high and low charges.
Why it seems that just after AC charging it happens.
Why no relation to miles seem to happen.