I have a 7kw gas powered generator (8,750 max) that I would like to be able to use to charge my Roadster. I built a cord using the proper male 30 amp plug to insert into the generator's 240 outlet and have a female 14-50 on the other end. I insert my UMC 14-50 into this new cord and then attach the cord to the car. I'm registering ~245 volts. When I attempt to charge (initially at only 15 amps) the car cycles through the start-up process - blue flashing - then goes to white and immediately to red. The car's display says "Line Voltage Lost Sync" and then a second screen is displayed "External Charger Problem". Can any of you help? btw - I had no problem using the 110 charger cord at 12 and 15 amps.