Build the EV part first, then add the generator. Plenty of people struggle just to build the EV.
Also, if you permanently install a combustion motor, your local vehicle licensing/registration authority may refuse to call it an EV, so you'd lose out on any low-emissions tax breaks.
Also, if you permanently install a combustion motor, your local vehicle licensing/registration authority may refuse to call it an EV, so you'd lose out on any low-emissions tax breaks.