jmz
100 W
Hi people, I'm making this thread to document the planning and construction of my first electric bike build, and to seek input on the design.
The candidate bike is this one here, a 700C commuter with a 19" frame, a Suntour swing shock fork, and dual mechanical 160mm disc brakes. I've had it for a few years, and I quite like it, the light weight and short frame contribute to snappy handling.
https://imgur.com/a/7sQle
I want to convert it for electric commuting. The roads are flat almost everywhere here, and my regular commute is 5km, so I do not require extreme speed, power or range, though more capacity than required for just the commute distance would be nice (and nicer on the batteries), as would extra torque for bike trailers.
As for relevant experience, I work as a power electronics engineer, so I have access to a full mechanical and electrical workshop, as well as all the high performance MOSFETs I could ever need.
My initial plan is for a 201rpm Cute Q100 build, running at 44-48V using hobby LiPos for a high discharge capacity relative to the small pack size I will realistically need, and get my existing rear wheel rebuilt with the motor. The multi-kW off road bomber will have to wait.
The big unknown is the controller. I am open to either COTS or DIY/open-source controllers, is there much of a consensus on the benefits of FOC for these small motors (i.e. will it enable higher powers/efficiency/effective bus voltage)?
Could possibly look at using a cheap OTS controller to start with, then experiment with rolling my own later. Other advanced considerations include integrated charging and monitoring, and also perhaps mechanical modification of the motor for heatsinking.
Does it look like the 160mm rear disc brake will present any problems with a Q100 motor? The space between the dropouts is 140mm, though I hear these can be pried apart some if required? I could take it as an opportunity to swap them out for some larger hydraulic brakes.
The candidate bike is this one here, a 700C commuter with a 19" frame, a Suntour swing shock fork, and dual mechanical 160mm disc brakes. I've had it for a few years, and I quite like it, the light weight and short frame contribute to snappy handling.
https://imgur.com/a/7sQle
I want to convert it for electric commuting. The roads are flat almost everywhere here, and my regular commute is 5km, so I do not require extreme speed, power or range, though more capacity than required for just the commute distance would be nice (and nicer on the batteries), as would extra torque for bike trailers.
As for relevant experience, I work as a power electronics engineer, so I have access to a full mechanical and electrical workshop, as well as all the high performance MOSFETs I could ever need.
My initial plan is for a 201rpm Cute Q100 build, running at 44-48V using hobby LiPos for a high discharge capacity relative to the small pack size I will realistically need, and get my existing rear wheel rebuilt with the motor. The multi-kW off road bomber will have to wait.
The big unknown is the controller. I am open to either COTS or DIY/open-source controllers, is there much of a consensus on the benefits of FOC for these small motors (i.e. will it enable higher powers/efficiency/effective bus voltage)?
Could possibly look at using a cheap OTS controller to start with, then experiment with rolling my own later. Other advanced considerations include integrated charging and monitoring, and also perhaps mechanical modification of the motor for heatsinking.
Does it look like the 160mm rear disc brake will present any problems with a Q100 motor? The space between the dropouts is 140mm, though I hear these can be pried apart some if required? I could take it as an opportunity to swap them out for some larger hydraulic brakes.