cozy35
10 W
- Joined
- Oct 23, 2013
- Messages
- 71
This is my effort in creating an affordable, powerful mid drive to enable me to enjoy the wilderness sort of effortlessly.
Criteria:
Powerful
Lightweight
Quick Install
Benefit of standard gearing on most bikes.
Reliable
I will be using the Alien Power Systems APS-6384-100KV Out-Runner. They have this motor in both sensored and sensorless. The ESC will be the Open Source Vedder VESC for it versatility. Standard E-Bike Controllers can also be used if the sensored motor option is used.
The APS 6384 100KV has massive torque of 6.9NM at the rated power of 4000W. I used the excel spreadsheet by Jaroslaw „Jaros” Berezowski for a more accurate simulation of power, torque, speed, inclines and range. I have a copy of a couple of years ago and used this successfully on many other electric vehicle projects. It does bit seem to be available anymore ad I had to go back in my backups to find it again.
My mid drive is primarily designed utilizing a two stage reduction drive of synchronous belts and pulleys and I selected the belt sizes with room to spare for stresses.
The drive will have two mounting options:
In the "V" above the bottom bracket for conventional hard tails and soft tails to the down tube and seat stay.
On carbon bikes or full suspension bikes the option will be under the down tube with side plates to anchor on the bottom bracket.
Reduction ration to output sprocket is 27.3:1 driving the 3rd front sprocket of 28T on my bike. I still have the 38T and 48T for front selection and from 12T to 28T on the rear wheel.
In high gear the ratio to the wheel is 6.8:1 which should provide a top end speed of 65KmH at an incline of 5%. Current draw at 58A @ 2110W. On the level at 65KmH, the current draw will be 19A @ 700W.
Pedal cadence will be 135 RPM, so that begs a front freewheel crank. I think for short bursts the average cyclist can achieve 120 RPM. I any case with 4000W power who needs to pedal?
In the low gear the ratio to the wheel is 20.1:1 and a maximum incline of 18% is achievable at a speed of 20KmH. Current draw at 37VDC is 43A @ 1585W.
All the above performance calculations was done using very conservative drive train, motor and battery efficiency numbers and tyre rolling and drag co-efficients.
My initial estimate of weight is around 1.58Kg without the battery pack. The 10S Lipo pack will ad another 2.4Kg.
I am still contemplating twist throttle or thumb, but field test will show the best option.
I will update my progress from time to time.
Criteria:
Powerful
Lightweight
Quick Install
Benefit of standard gearing on most bikes.
Reliable
I will be using the Alien Power Systems APS-6384-100KV Out-Runner. They have this motor in both sensored and sensorless. The ESC will be the Open Source Vedder VESC for it versatility. Standard E-Bike Controllers can also be used if the sensored motor option is used.
The APS 6384 100KV has massive torque of 6.9NM at the rated power of 4000W. I used the excel spreadsheet by Jaroslaw „Jaros” Berezowski for a more accurate simulation of power, torque, speed, inclines and range. I have a copy of a couple of years ago and used this successfully on many other electric vehicle projects. It does bit seem to be available anymore ad I had to go back in my backups to find it again.
My mid drive is primarily designed utilizing a two stage reduction drive of synchronous belts and pulleys and I selected the belt sizes with room to spare for stresses.
The drive will have two mounting options:
In the "V" above the bottom bracket for conventional hard tails and soft tails to the down tube and seat stay.
On carbon bikes or full suspension bikes the option will be under the down tube with side plates to anchor on the bottom bracket.
Reduction ration to output sprocket is 27.3:1 driving the 3rd front sprocket of 28T on my bike. I still have the 38T and 48T for front selection and from 12T to 28T on the rear wheel.
In high gear the ratio to the wheel is 6.8:1 which should provide a top end speed of 65KmH at an incline of 5%. Current draw at 58A @ 2110W. On the level at 65KmH, the current draw will be 19A @ 700W.
Pedal cadence will be 135 RPM, so that begs a front freewheel crank. I think for short bursts the average cyclist can achieve 120 RPM. I any case with 4000W power who needs to pedal?
In the low gear the ratio to the wheel is 20.1:1 and a maximum incline of 18% is achievable at a speed of 20KmH. Current draw at 37VDC is 43A @ 1585W.
All the above performance calculations was done using very conservative drive train, motor and battery efficiency numbers and tyre rolling and drag co-efficients.
My initial estimate of weight is around 1.58Kg without the battery pack. The 10S Lipo pack will ad another 2.4Kg.
I am still contemplating twist throttle or thumb, but field test will show the best option.
I will update my progress from time to time.
