This is based on a wrong premise, that 900 watts is needed to keep the thing from losing charge, derived from vague anecdotal evidence and not supported in any

This is based on a wrong premise, that 900 watts is needed to keep the thing from losing charge, derived from vague anecdotal evidence and not supported in any way by technical fundamentals. If it was true, the 85 kwhr battery pack would last less than 3 days when the car was unplugged. The actual number is probably more than an order of magnitude smaller.