Is it possible to do something like put a gas generator on a tow hitch platform and charge as you drive for a longer range extension? I am guessing the manufacturers don’t let you charge as you drive but I am curious if there are theoretical blockers to this.
what you are describing is a PHEV (plugin hybrid electric vehicle). The Chevy Volt and Toyota RAV4 Prime are examples of that. Those vehicles are intended to address range anxiety, not charging speed.
Trying to do it with a Mickey Mouse contraption like a generator in a trailer would likely be inefficient and inconvenient compared to an integrated system like a PHEV. Generators are not as efficient as just getting electricity directly from power lines. PHEV's engines are there to power the vehicle when the battery is depleted. they don't try to recharge the battery as that would cost more than just plugging in on a charger.
