Hi,
I’m building a set of electronics pieces to replace with opensource licence each part of a low powered electric bicycle. I’ve already done some experimental parts for prototyping only, http://olivier.gelux.ch/?q=taxonomy/term/36 I think that sparkfun could be interested somewhere 
Regarding our specific usecase, we did a list of features that will be developed,
- keep the bicycle minimal and beautiful,
- our electric bicycle kit doesn't overcharge the bicycle it's light! without battery you can still use your bicycle,
- the bicycle could be used as battery charger with a X% of human power shared for this usage,
- the battery could be used for other purpose like led lighting or laptop power supply,
- the charger is small you can carry it everywhere to recharge the battery on demand with a lot of power source (laptop power, solar panels,.. ),
- the hub motor is ultra small with a power from 220W to 250W for less than 2.0kg,
- no pedal assist, no useless wire, you press a boost button (ideally wireless) when you need help or when you want recharge the battery,
- the kit construction will be available on opensource license
After, reading and learning about electronics and electric bicycle, I have a better idea on what should be done to make this a real product. And regarding my freetime (this is not currently a business project) here is my roadmap,
- make custom battery real. with battery protection, and battery charger (the charger will be small and pluggable with several source of power as laptop power or solar panels : input 19-24V/4A), *- this has already started and will be published soon on github* [[LTC3862-2](http://www.linear.com/product/LTC3862-2), [[LTC3873-5](http://www.linear.com/product/LTC3873-5), [[BQ77910](http://www.ti.com/product/bq77910a)
- make custom bldc motor controller [[TMC603](http://www.trinamic.com/index.php?option=com_content&view=article&id=191&Itemid=301),
- manage I/O (throttle, breaks, power, data log ) with several devices, (bluetooth, rfm12b, etc..) ](http://www.trinamic.com/index.php?option=com_content&view=article&id=191&Itemid=301)
This is a freetime opensource project with source available here https://github.com/evaletolab, I’m not an expert with those subjects and I will really appreciated technical help or any participation!
Olivier](http://www.ti.com/product/bq77910a)](LTC3873-5 Datasheet and Product Info | Analog Devices)](http://www.linear.com/product/LTC3862-2)