"Rare" and "hard-to-find" are distinct. If you have $5-7k to spend, you can pick up a Smart ED very easily in the States, and could probably recoup a grand from that, depending on your level of patience with selling the rest of the car.
I'm not saying that you can't get them, only that there are fewer and so it shouldn't be surprising that they are less commonly salvaged than other EVs.
I don't mean to trivialize the actual conversion costs, but how much is a Leaf or Tesla battery pack alone? Is a $5-8k Leaf just a better place to grab components?
The Leaf provides more battery, and a more powerful motor. If you don't need those that's fine, but for most people it does make a Leaf a better source.
You need to make the battery, controller/inverter, motor, high-voltage protective switching, and battery charging all work together. There are various approaches to that, and how much of the original electronics you want to use affects what combinations will work... and what experience from other projects can be adopted. Working with stuff that others have used is an advantage in that way, but it isn't the only valid approach.
The hardest part of installing an electric drive train is getting the motor to drive the wheels, right? Why would that be harder with a Smart motor than anything else? A lack of existing adapters?
I don't know if that the hardest part, or if it would be any harder with the Smart components. Any transverse motor and transaxle assembly would be complex and difficult to install in the back of an MGB, which is why I asked if that was the plan.
If the idea is to use just the Smart motor with the MGB transmission (so I'm still asking:
is that the plan?) then a Leaf isn't easy either... yes, because of the lack of an available coupler for the shaft (and an adapter for the housing, but that's probably easier than the coupler). That's true of almost any production EV, since they have splined motor shafts designed to work with dedicated transmissions, not with the transmission which happens to be in a gas-engined car to be converted. Readily available conversion parts are designed to work with motors from forklifts, and similar motors from conversion suppliers which follow industrial face-mounting patterns and have plain shafts.
The Smart has 120 ft-lb of torque at 0rpm. Not a powerhouse, but more than half the Miatas out there.
That's probably more torque than a gasoline or diesel Smart ForTwo, but that's not the issue. It's also not the right value: the second-generation Smart ED motor put out up to 120
newton-metres (that's 89 lbf⋅ft), and the third-generation puts out up to 130 newton metres (96 lbf⋅ft) (according to specs quoted in Wikipedia, which seem plausible and are supported by references).
The issue for many conversions would be power:
- second generation
- 20 kW (27 hp) continuous; peak power output of 30 kW (40 hp) for approximately 2 minutes
- this is really not very much
- third generation: peak power output of 55 kW (74 hp)
- this is comparable to the diesel Smart ForTwo, but low by current EV standards
No Miata (or MGB) in reasonable running condition would be comparable in power output to either generation of Smart ED, although an early Miata's or MGB's torque at low engine speeds would be inferior to these electric motors... which is why there's a transmission.
