After building electric skateboards some years ago, I decided to try my luck with a folding bike to use for my commute. Inspired by Kepler I chose a friction drive to keep it light and simple. To give back some of the inspiration I got from this forum, I'd like to share my build with you.
I went with the idea of a sliding mechanism instead of a pivot point based one since I had a sample linear slide left over which seemed the perfect fit. To save on money, mostly used and leftover old components from my board building days were used and everything came together pretty well.
Components:
VESC 4.7
Alienpower 6375 BLDC Motor (can't remember the Kv, but was pretty low)
36V nominal DIY Battery from used Makita 18650 cells (10s3p)
New thumb throttle for 5 bucks
Going with a sliding engagement of the motor, I used the angle of the rear wheel bracket as an attachment point for the slide, hoping that the geometry would work out. First, springs were tested to take the motor weight, so it could engange by the starting jolt, just like the pivot point friction drives. This did not work out, probably just does not work with a sliding mechanism. So I decided to use the pivot point for the rear suspension of my bike to attach a foot lever which would engange the motor. This method works pretty well, but without a lock of some kind, I always have to keep my heel on the lever to keep the motor enganged. This means there is no assisted driving mode.
The 10s3p battery cells fit retty well insinde a small outdoor case I had left over but there was no room to add a swith of seperate charge port.
The VESC and switch were supposed to sit in a 3D printed enclosure just above the sliding mechanism, but were just a little too bulky. Now they are kept in a seat bag, along with 3 extra capacitors. Sadly, that means way more cable handling than I hoped for and the stealth effect gone out the window.
Overall, the bike works OK. I was hoping for way more power with that motor and 10s3p battery, setting the VESC to 40A max. On a flat road, I can get up to 45km/h. Going up a hill or riding on rough roads is no fun at all, the motor stutters a little at low speeds and just decelerates slowly until it can't push me up the hill anymore. The VESC regulates the power further down due to the temperature limit and the seat bag does not have the best cooling.
I am now looking to add a latch that keeps the motor enganged, so I can help with pedalling. On the other hand, I would like a more 'fun' machine, so maybe I will scrap the friction drive idea and look for a stealthy and powerful rear hub motor. Does anyone have some recommendations?
Let me know if you have and ideas for better performance (might just be the nature of a friction drive tho) or want to see any detail.
I went with the idea of a sliding mechanism instead of a pivot point based one since I had a sample linear slide left over which seemed the perfect fit. To save on money, mostly used and leftover old components from my board building days were used and everything came together pretty well.
Components:
VESC 4.7
Alienpower 6375 BLDC Motor (can't remember the Kv, but was pretty low)
36V nominal DIY Battery from used Makita 18650 cells (10s3p)
New thumb throttle for 5 bucks
Going with a sliding engagement of the motor, I used the angle of the rear wheel bracket as an attachment point for the slide, hoping that the geometry would work out. First, springs were tested to take the motor weight, so it could engange by the starting jolt, just like the pivot point friction drives. This did not work out, probably just does not work with a sliding mechanism. So I decided to use the pivot point for the rear suspension of my bike to attach a foot lever which would engange the motor. This method works pretty well, but without a lock of some kind, I always have to keep my heel on the lever to keep the motor enganged. This means there is no assisted driving mode.
The 10s3p battery cells fit retty well insinde a small outdoor case I had left over but there was no room to add a swith of seperate charge port.
The VESC and switch were supposed to sit in a 3D printed enclosure just above the sliding mechanism, but were just a little too bulky. Now they are kept in a seat bag, along with 3 extra capacitors. Sadly, that means way more cable handling than I hoped for and the stealth effect gone out the window.
Overall, the bike works OK. I was hoping for way more power with that motor and 10s3p battery, setting the VESC to 40A max. On a flat road, I can get up to 45km/h. Going up a hill or riding on rough roads is no fun at all, the motor stutters a little at low speeds and just decelerates slowly until it can't push me up the hill anymore. The VESC regulates the power further down due to the temperature limit and the seat bag does not have the best cooling.
I am now looking to add a latch that keeps the motor enganged, so I can help with pedalling. On the other hand, I would like a more 'fun' machine, so maybe I will scrap the friction drive idea and look for a stealthy and powerful rear hub motor. Does anyone have some recommendations?
Let me know if you have and ideas for better performance (might just be the nature of a friction drive tho) or want to see any detail.
