I have had some problems with the "15 amp" charger popping my 15 amp circuit breaker.
Right when the charger starts, it pulls a lot of amps. Enough to pop the breaker fairly routinely.
So, I installed a 20 amp circuit breaker in my garage breaker box.
I then installed a 20 amp electric outlet with a built-in GFI directly below the breaker box.
I now have a home-made Electric Vehicle Charging Station! (I just need to make a sign!)
Another advantage of this is that the new outlet is about 10 feet closer to the front of the garage than the closest 15 amp outlet was.
Before, the 25' 12 gauge extension cord would just barely reach if I had the car parked in the driveway facing the garage. Now I have plenty of reach.