Making An Electric Bicycle.
 

That's what I'm doing. Instead of buying a kit I've bought all the parts. A 600w brush motor, a #25 chain, a #25h drive sprocket, a freewheel for the chainset, 80 186650 li-on batteries, a 36v battery management system, a 36v battery charger for lithium batteries, a motor controller, a throttle, a freewheel chainset, and various connectors and sundry nuts and bolts. I'll post a picture when I'm I'm finished. I reckon I'm saving a hundred dollars or two doing it this way. Mainly because the batteries are so expensive, and I'd have to pay VAT if I bought a complete kit.

Good luck!

I think I need to fork out another €100. I need a Battery Management System and a 36 volt li-ion charger. This may put this off till Christmas.

I'm not waiting till Christmas. So this thing must be costing me circa $300, not including bike.

Soldering the batteries together is a bitch. It's just so difficult. I've sanded down the terminals, but getting good solder joints is a nightmare. This could turn out to be a huge waste of money.