iluvmacs
Member
First, the limiting factor in this case is more the charger in the car than the EVSE you use (i.e. it isn't specifically relevant if you use a Tesla EVSE or a J1772). Yes, the EVSE must also be rated for the voltage, so both do factor in, but the point is that in no way can changing the EVSE help you here. Second, the car can take up to 277V power, typical industrial voltage, though unusual in the EV world (I don't believe any other vehicle or EVSE has been designed for 277V). No dice on 347V though, so yes you will need to step it down. It will be far cheaper and just as effective with a buck-boost transformer than with a standard isolation transformer, since you wouldn't have an isolation requirement. If you get the older HPWC that supports 277V, you could step down to that. If you are using a UMC or v3 HPWC, go to 240V. No reason to go all the way down to 208V.