I understand the math behind it, but I don't understand the limitation. The Model S onboard charger supports up to 10kW which is about 29 MPH charge rate. On my 240V UMC at home, I achieve that rate. I don't charge publicly very often and the first time I charged at a Tesla store, I was disappointed to only get 24 MPH. I understand the math behind it. At home, 240V x 40A = 10,000W (+/-). Commercial buildings are 208V so 208V x 40A = 8,000W (+/-). 80% of 29MPH = 24MPH. What I Don't understand is the limitation. Why can't an 80A/20kW charger, charge my car at 29 MPH like my 40A UMC can at home? It certainly has the power to do so. There should be a way to mitigate that limitation. Any ideas? if the onboard charger is limited by AMPs, why do they call it a 10kW charger and not a 40A charger? The limit is abviously in AMPs, not Watts. So, anyone who will be charging for the first time at a commercial UMC, be prepared to charge 20% slower than you can at home.