[AKBeemer]

If by cigarette lighter you mean the auxiliary port, then yes you can charge there. In fact, the BMW charger uses the port. My only concern is that your charger may overload the auxiliary circuit and the bike's computer shuts it down. I do not think that will happen but it could I suppose. You'll need to have the ignition on when you first start charging. That allows the computer to sense the charger and keep the circuit functional on once you turn the ignition off.

 

[AKBeemer]

I would not risk it unless your generator is also an inverter. Otherwise there may be a energy spike that may or may not make it to your ZFE computer.