[GianFabien]

I have come across several businesses that do conversions. Batteries are by far the biggest issue. ICE cars can't easily accommodate sufficient batteries. All the conversions I have looked at connect the electric motor to the gearbox with rear wheel drive cars. The range is only 200-300 mile at best. Getting cars roadworthy and certified after a conversion is a substantial exercise.

Unless you are converting a rust free, mechanically sound classic car, the typical conversion cost is just too much to be a realistic option.

[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.

[HeyLaughingBoy]

Why does it need to be "certified?"

You have an existing car with an existing title and registration. You replace the motor and drive off. What's the problem?

Then again, I live in MN, which doesn't have vehicle inspections.

[GianFabien]

In Oz, the vehicle standards regulations are over 500 pages. You have to have an engineer's certificate after any modifications in order to re-register the vehicle. That also applies to changing the ICE for a different one, etc. Technically even changing the ECU program is verboten. But people still do it and plug in the old ECU to pass inspections.