There are quite a few places to get kits in Australia actually and they seem to be becoming much more popular these days. I tried one from Golden Motors in China and it worked well for nearly a year. I tried one from a business called Electric Transport Australia and it was so crap, he supplied me with the wrong charger and when I finally got one from elsewhere and took it for a ride 5 spokes fell out before I even turned the first corner - no refund was possible the bastard. Not to be dissuaded I got another one from a business called Solar Bike. These were really good, came with a lithium ion battery and nearly a year now with no problems at all. Check it out: http://www.solarbike.com.au
Hopefully I won't have to try too many more.
