It looks like they have two different kinds, for sale in India. I think this is a great idea for a cottage industry income combined with off grid living. It's like some of the early spinning gennies.
The single charkha is a lot like the old style, but no accelerator, so it probably spins at 40 to 1 which is okay. It could support a fairly wide range of yarn, but would do best with a short staple fibre like cotton.
Not sure what kind of yarn or efficiency the double e-charkha could create. It would be fun to try.
here's where you buy them. Minimum order 500 units but only $100 each whole sale. Spins two threads at once, generates electricity and includes an onboard battery.