I appreciate your concern, but it’s unfounded. If EVs needed to be plugged in when parked for more than 24 hours, the internet would be flooded with posts and videos of people stranded at ski resorts, airports, in apartment complexes, etc.
There are a lot of Tesla owners who don’t have home charging and who leave their cars unplugged for extended periods of time.
Our second Model 3 (a mid-range battery) has been parked at home, unplugged, for 8 days over Thanksgiving week and has only lost 3%. I just checked it for the first time since we left, as the screenshots below show. Not sub-zero weather, but it’s been below freezing for a good chunk of that time.
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