To be clear: I faked that picture. The "on-board charger" is a BRUSA NLG6. In contrast to that, Tesla indicated they might cram 3 of their 10kW on-board units into the charger bay, connecting each one to a different phase, and deal with the excess thermal load. I am by no way qualified to judge the electric efficiency of that, but the economical efficiency seems to be top priority here.