DeadParrot
10 µW
- Joined
- Jul 7, 2021
- Messages
- 6
Hi All
I am at the very early stages of planning an e-motorbike build as I am going to be moving in the next year of two which will see me having a 20 mile commute. I have spent the past few days researching and reading through as many threads as I can to get a good grasp of what will be involved and to set my expectations for what will be achievable. I am at the point where I'm looking for feedback on my line of thinking and any advice on how best to start out. My background is in engineering and I would say I have functional (if rudimentrary) metalworking skills, though I have access to skilled machinists/welders through my work. I am a keen cyclist and am mechaincally minded, though this will be my first motorbike!
The bike will be used for a 20 mile journey that is an even mix of hilly country roads, city driving and then a short stretch of 50mph dual carriageway (slightly uphill). I have the following requirements
50-60 mph top speed
50-60 mile 'typical' range (given the terrain I will be covering I want a good amount of margin)
Good torque/uphill accelleration when needed
Donor bike
I'm in the UK so a conversion from a 50cc or 125cc will allow me to ride on my current driving license after a basic test. Registering the conversion with the DVLA seems fairly easy. My preference is for a 125cc as this will leave room for upgrades down the line. As I have barely any direct motorbike experience any tips on specific models that make good donor bikes is welcome. I've found an excellent thread on the conversion of a 50cc Chinese Yahamha clone (Yamasaki YM50-RE) that I am using as inspiration (https://endless-sphere.com/forums/viewtopic.php?f=12&t=105463).
Motor
My initial thoughts are that a 4kW motor should meet my needs. Whether I go for hub or mid-mount will likely depend on the bike (unless my requirements dictate one or the other). I would really appreciate feedback as to whether a hub motor is suitable for hilly terrain, or whether a geared mid-mount is more suitable (at the cost of battery space). I know there is a QS138 70H V3 3kW mid mount with built in reduction gear but I don't know if a 3kW motor would be sufficient.
Battery
Honestly the finer details of the electrics is the part of the build I am struggling to get my head around, but I see this as a good project to finally get a good understanding of the subject. Again, would really appreciate feedback on what would be suitable. Reading around it appear the pandemic has impacted the supply chain somewhat to sourcing an affordable battery pack may be tricky. Given this, I am leaning towards using a 2nd hand EV battery if I can get a good price on one. I have been looking at a BMW i3 battery module which is 44v,96Ah which has 12 cells in series. Providing the donor bike can fit them all in, could this be re-configured to give the speed/range I want? Alternatively if building a custom pack from new cells more suitable I'm happy to be steered in that direction.
Controller/supplimentary electrics
I'm waiting until the other components are specified and then I will most likely be seeking additional advice to souce a suitable controller, but any advice is welcomed
My back of the envelope costing for the project is around £2000 for the donor bike and conversion. Please let me know if I am being wildly overoptimistic (or if this could be scaled back - somehow I doubt it!)
I am at the very early stages of planning an e-motorbike build as I am going to be moving in the next year of two which will see me having a 20 mile commute. I have spent the past few days researching and reading through as many threads as I can to get a good grasp of what will be involved and to set my expectations for what will be achievable. I am at the point where I'm looking for feedback on my line of thinking and any advice on how best to start out. My background is in engineering and I would say I have functional (if rudimentrary) metalworking skills, though I have access to skilled machinists/welders through my work. I am a keen cyclist and am mechaincally minded, though this will be my first motorbike!
The bike will be used for a 20 mile journey that is an even mix of hilly country roads, city driving and then a short stretch of 50mph dual carriageway (slightly uphill). I have the following requirements
50-60 mph top speed
50-60 mile 'typical' range (given the terrain I will be covering I want a good amount of margin)
Good torque/uphill accelleration when needed
Donor bike
I'm in the UK so a conversion from a 50cc or 125cc will allow me to ride on my current driving license after a basic test. Registering the conversion with the DVLA seems fairly easy. My preference is for a 125cc as this will leave room for upgrades down the line. As I have barely any direct motorbike experience any tips on specific models that make good donor bikes is welcome. I've found an excellent thread on the conversion of a 50cc Chinese Yahamha clone (Yamasaki YM50-RE) that I am using as inspiration (https://endless-sphere.com/forums/viewtopic.php?f=12&t=105463).
Motor
My initial thoughts are that a 4kW motor should meet my needs. Whether I go for hub or mid-mount will likely depend on the bike (unless my requirements dictate one or the other). I would really appreciate feedback as to whether a hub motor is suitable for hilly terrain, or whether a geared mid-mount is more suitable (at the cost of battery space). I know there is a QS138 70H V3 3kW mid mount with built in reduction gear but I don't know if a 3kW motor would be sufficient.
Battery
Honestly the finer details of the electrics is the part of the build I am struggling to get my head around, but I see this as a good project to finally get a good understanding of the subject. Again, would really appreciate feedback on what would be suitable. Reading around it appear the pandemic has impacted the supply chain somewhat to sourcing an affordable battery pack may be tricky. Given this, I am leaning towards using a 2nd hand EV battery if I can get a good price on one. I have been looking at a BMW i3 battery module which is 44v,96Ah which has 12 cells in series. Providing the donor bike can fit them all in, could this be re-configured to give the speed/range I want? Alternatively if building a custom pack from new cells more suitable I'm happy to be steered in that direction.
Controller/supplimentary electrics
I'm waiting until the other components are specified and then I will most likely be seeking additional advice to souce a suitable controller, but any advice is welcomed
My back of the envelope costing for the project is around £2000 for the donor bike and conversion. Please let me know if I am being wildly overoptimistic (or if this could be scaled back - somehow I doubt it!)