Thanks for the reply, hiroshly. Most generators rely on rotating magnets or rotating coils in a magnetic field, and are, by this design, inherently sine wave. Many less expensive inverters, on the other hand are modified sine wave, better described as modified square wave. I would not expect modified sine/square wave inverters to charge a Tesla. As I understand it, the issue is if the UMC will accept a 'spoofed' ground from an ungrounded generator, and designing the 'spoof' to be as safe as possible. There are a number of reports that a grounded generator or a bonded generator, Honda EB2000i, for example, (not EU2000i), will charge OK. Remember that I'm still waiting on my M3, hopeful for Q1 2019 delivery. I'll probably have to wait to sort all this out until I get it. Using an ICE generator is only going to be an emergency, power-outage backup, anyway. If I am able to use my 6KW Winco generator, which only puts out about 5.0KW sustained when running on natural gas, and derate that to 80%, that's 4.0KW going into the M3's battery, or on the order of 16 mph charge rate.