So... one question has been answered via the Tesla Energy web-site... the power wall is intended to be DC-coupled with 350-400vdc. How does it work off-grid? There are really only two options. UL1741 grid-tied inverter DC-coupled to power wall is AC-coupled to off-grid inverter. - What powers the off-grid inverter? Do you need another smaller battery? Kinda like the 12v battery in a Tesla? Some kind of Hybrid inverter. To my knowledge there is currently no off-grid capable inverter that can use ~350vdc like the power wall uses.... I'm sure WK057 researched this EXTENSIVELY... it would have saved him A LOT of trouble. UL1741 inverters CANNOT regulate the power output... does the power wall manipulate output by 'tinkering' with the MPPT algorithm? 'Tricking' the grid-tie inverter into thinking less power is available from the array/battery?