[vba616]

Because I enjoy the torque of an electric motor, but not the weight of a battery, I have a dream of making a simple series hybrid from a classic car, with a motorcycle (sized) engine and a battery and a high torque electric motor.

Last I noticed, a non-plugin hybrid only needs 1% of the battery capacity. You could have a gas engine half the size or less, and you don't need a transmission either.

Unfortunately when I look at the available hardware for EV conversions, I get the impression that a battery pack has to be a certain size to get fast enough discharge and high enough voltage for a powerful motor like a Tesla's.

But imagine a classic rear-engine Porsche with, say, a boxer twin (from a BMW motorcycle, or I think there are twins made from/like half of a VW four used for small aircraft) and an EV motor that actually improved the weight distribution from stock.