David Southern might be able to comment.
My build was for chainwheel drive. AC member Mic Chapman supplies Ebikes (hub drive).
There are two types of hub drive: direct drive (like the motor on a modern washing machine); and internally geared. For the latter, the motor revs at a higher RPM than the wheel, and so is probably/possibly a bit more efficient in terms of battery consumption. These generally have an internal freewheel so there is less drag when not motoring.
No currently available hub drive has gears available to the motor. This could be a severe disadvantage for hard hill climbing (hence my chainwheel drive).
When choosing a kit of any type, one needs to consider load (bike, rider, load carried), terrain, and range. Do you want to sometimes use power while not pedalling? If you do, then you will need a kit that delivers a maximum output power of 200W (or less). If you are content to have the assistance interlocked with pedalling, then your kit can be for a rated output of up to 250w.
See this AC discussion for some other riders' experiences.
An ebike is my primary transport at the moment and I prefer to take it than my (sporty) car.
I'm not a fan of the kits sold on ebay as most of them are overpriced junk.
I'd point out a few comments - the connectors on all the cheap kits are junk and will lead to issues if you do serious kms. Some motors are significantly higher quality than others. I am a big fan of geared hub motors too, but they don't take sustained abuse like I have given mine (off roading, regular high speed kerb hopping etc). If you don't do that then they can be quite reliable.
A high quality battery is essential. I bought a battery pack with a123 cells and they are just shy of 90% of original capacity after 15,000 km and well over 600 recharge cycles. Stay away from lead-acid and unknown branded lithium ion cells. If you want your battery pack to last, you need to over-spec its capacity for a typical trip by about 40%. Not draining the last 10% of the battery capacity is what lets them last a long time.
Lastly, the 200w limit is um, lame.
Online discussion is mostly at endless-sphere.com, but there is also discussion elsewhere, for example on Whirlpool:
thanks guys. do you have any pics of your bikes and info on kits or parts you have?
Excellent places to learn e-bike stuff:
- e-bike.ca - Canadian retailer and product developer with very informative site
- Em3ev - Shanghai-based web retailer with excellent and informative site and about the only place I'd go - apart from e-bike.ca to buy a hub kit! Em3ev have a good representative selection of the 3 major forms of electric assist - crank, geared hub and direct drive hub.
Locally, Mike Chapman, Chair of the Electric Vehicle Assoc'n (I think) and e-bike consultant/builder/fixer (workshop at Thebarton) is someone to contact who knows his stuff.
Fully support the comment above about battery quality and design - probably the most important bit in an e-bike set up.
Although it's extremely easy to exceed the Australian 250watt limit, 250watts in an efficient package is actually very useful and probably just about ideal for the ordinary city commuter.
I guess it comes down to how fast/far do you want to ride, what terrain, how light you want it and how much you can spend?
A fair summary.
Hi Mic, good luck with the opening of your store. I'll probably head down and have a chat one day when you're open. :)