Jarno:
rosco62: The ones in the shops are pissy underpowered 250 or 350 watt units and expensive. I bought a hub motor kit from Luna Cycles in the US, 52 volt, 1500 watts.
Just don't use it on the road. In New Zealand electric bikes are limited to 300 watts by law. Otherwise they are no longer considered bicycles, but more like motorbikes with the associated requirements of licensing and registration.
Easily resolved with a sticker that says 300W.
E-bikes look like great EV option. I have 5-minute walk to work so no need but I like the idea. A few people in Nelson have them in trike configuration with a useful looking cargo/dog tray at the back.