Kepler Friction drive comes of age.

Water proofing the Vesc-x ? I'm thinking of housing it in a small plastic box with the side cut out to expose the heatsink.

Also thinking about this motor

http://www.michobby.com/product/electric-skateboard-brushless-motor-6355-170kv/

12s , 3000w waterproof. 147kv may be too low on a 26 tyre ?
 
I have had an idea for my own friction mount modifying the same mount as in my sig build. It would allow more pressure on the wheel if you need it. However I wonder how well the bell will take the extra pressure since the front of the bell is a plastic fan, or if the bearings are strong enough for pressure on the bell.
 
Hey Kepler. Got any thoughts about doing this in carbon fibre? Might be cheaper and easier to produce since there are so many people milling quadcopter parts these days.
 
I have had some parts cut by a guy up here in Canada and have had work done at some larger production houses.

I'd love to give it a try.
 
I'm wondering what you all think would be a highest power motor / controller / battery combination that would be possible with Keplers new friction drive....

Lets say cost and weight aren't issues.... and lets say you'd like to go as fast as possible with high acceleration for up to 15 miles approx.... on flat terrain not taking wind into consideration.

Lot's of variables I know, but any thoughts?
 
Finally got time to test my customised infineon 6fet sines. Syncs up nicely to the sensored eskate motor. Will get in touch Kepler.


Sent from my iPhone using Tapatalk
 
Look forward to testing one and seeing how it performs and sounds. Need to keep in mind this is a sensored solution so a bit more complication with the wiring and of course a sensored motor is required. However, sensored motors are not to hard to find now thanks to the skateboard guys.
 
for liamcaff regarding power levels the limit is not going to be the battery or controller but getting power into the tyre without motor slip, I have a homemade friction drive similar to kepler's, I could not use his bracket on my bike as the bb does not have any room left on the thread under the lock ring to fit his mount. So I made my own out of some 50x50x5mm alloy angle extrusion, a heavy steel door hinge and some coathanger wire for the spring. the angles could have been better as it initially struggled to engauge with low power settings but would climb the tyre at full power easily and bite in. It is a very fine balance with tyre pressure between too little and motor slip and too much and motor slip, too little and there is inadequate pressure against the motor can and too much and there is too little tread wrap surface area against the tyre. The best i can get is around 800 watts with a slick 2"x26 tire. i think the closer to over centre the lever angle of the motor the better the partial power performance is bit the less deeply it bites in to the tyre and the less possible tread wrap you will get. i have not tried grip tape on the motor yet i rekon this could give higher power levels but would shread the tire fast. I think Im doing well to get 800w into the tire as Kepler says he only gets around 400 to 500 max (Kepler please correct me if im wrong ) but his bike is a racer with skinny tires maybe a fatter 2.25 or 2.5" would get more power

I use a multistar 20ah 6s lipo brick for power and a vesc-x controller with a 6354 200kv motor the top speed is about 35kmh and it gives me about 40km range on the flat or 25km towing my daughter in her two wheel trailer with heaps of shopping on the way home ,the thick alloy bracket really helps with heat disipation
if I program the vesc for more than 40 battery amps i get lots of tire slip and no gain just a touchy throttle I added an elastic strap to lift the motor harder against the tire and it is much better with it no motor slip anymore at low power levels I can cruise at all throttle settings with no slip or motor bounce. the motor drag is hardly noticeable
 
mechhead said:
for liamcaff regarding power levels the limit is not going to be the battery or controller but getting power into the tyre without motor slip, I have a homemade friction drive similar to kepler's, I could not use his bracket on my bike as the bb does not have any room left on the thread under the lock ring to fit his mount. So I made my own out of some 50x50x5mm alloy angle extrusion, a heavy steel door hinge and some coathanger wire for the spring. the angles could have been better as it initially struggled to engauge with low power settings but would climb the tyre at full power easily and bite in. It is a very fine balance with tyre pressure between too little and motor slip and too much and motor slip, too little and there is inadequate pressure against the motor can and too much and there is too little tread wrap surface area against the tyre. The best i can get is around 800 watts with a slick 2"x26 tire. i think the closer to over centre the lever angle of the motor the better the partial power performance is bit the less deeply it bites in to the tyre and the less possible tread wrap you will get. i have not tried grip tape on the motor yet i rekon this could give higher power levels but would shread the tire fast. I think Im doing well to get 800w into the tire as Kepler says he only gets around 400 to 500 max (Kepler please correct me if im wrong ) but his bike is a racer with skinny tires maybe a fatter 2.25 or 2.5" would get more power

I use a multistar 20ah 6s lipo brick for power and a vesc-x controller with a 6354 200kv motor the top speed is about 35kmh and it gives me about 40km range on the flat or 25km towing my daughter in her two wheel trailer with heaps of shopping on the way home ,the thick alloy bracket really helps with heat disipation
if I program the vesc for more than 40 battery amps i get lots of tire slip and no gain just a touchy throttle I added an elastic strap to lift the motor harder against the tire and it is much better with it no motor slip anymore at low power levels I can cruise at all throttle settings with no slip or motor bounce. the motor drag is hardly noticeable


how much phase amps do you set?
 
mechhead said:
It is a very fine balance with tyre pressure between too little and motor slip and too much and motor slip, too little and there is inadequate pressure against the motor can and too much and there is too little tread wrap surface area against the tyre. The best i can get is around 800 watts with a slick 2"x26 tire. i think the closer to over centre the lever angle of the motor the better the partial power performance is bit the less deeply it bites in to the tyre and the less possible tread wrap you will get. i have not tried grip tape on the motor yet i rekon this could give higher power levels but would shread the tire fast. I think Im doing well to get 800w into the tire as Kepler says he only gets around 400 to 500 max (Kepler please correct me if im wrong ) but his bike is a racer with skinny tires maybe a fatter 2.25 or 2.5" would get more power

The optimum tire bite is if you draw an imaginary line from the pivot point on the swing arm, through the centre of your motor, and through your wheel hub. I tend to set them up with a few degrees less with lower powered systems I think you get a smoother action this way. I agree 800W is about the limit. But thats not the design intent. Its all about ultra light weight which means small battery which in turn means low power if you want to get any reasonable range out the pack.

I think the sweet spot in 250 Whr battery and a switchable between 200W and 400W.

With grip tape using a 6374 motor and a hard compound 2" tire, I have run 1500W without any slip. It worked fine but I really dont see the point.
 
mechhead said:
for liamcaff regarding power levels the limit is not going to be the battery or controller but getting power into the tyre without motor slip, I have a homemade friction drive similar to kepler's, I could not use his bracket on my bike as the bb does not have any room left on the thread under the lock ring to fit his mount. So I made my own out of some 50x50x5mm alloy angle extrusion, a heavy steel door hinge and some coathanger wire for the spring. the angles could have been better as it initially struggled to engauge with low power settings but would climb the tyre at full power easily and bite in. It is a very fine balance with tyre pressure between too little and motor slip and too much and motor slip, too little and there is inadequate pressure against the motor can and too much and there is too little tread wrap surface area against the tyre. The best i can get is around 800 watts with a slick 2"x26 tire. i think the closer to over centre the lever angle of the motor the better the partial power performance is bit the less deeply it bites in to the tyre and the less possible tread wrap you will get. i have not tried grip tape on the motor yet i rekon this could give higher power levels but would shread the tire fast. I think Im doing well to get 800w into the tire as Kepler says he only gets around 400 to 500 max (Kepler please correct me if im wrong ) but his bike is a racer with skinny tires maybe a fatter 2.25 or 2.5" would get more power

I use a multistar 20ah 6s lipo brick for power and a vesc-x controller with a 6354 200kv motor the top speed is about 35kmh and it gives me about 40km range on the flat or 25km towing my daughter in her two wheel trailer with heaps of shopping on the way home ,the thick alloy bracket really helps with heat disipation
if I program the vesc for more than 40 battery amps i get lots of tire slip and no gain just a touchy throttle I added an elastic strap to lift the motor harder against the tire and it is much better with it no motor slip anymore at low power levels I can cruise at all throttle settings with no slip or motor bounce. the motor drag is hardly noticeable


Sorry I'm only seeing this post now. Gonna do a lot more research into suitable motors today before I bite the bullet...

Thanks for the advice!
 
I will patiently wait for a kickstand/bottom bracket mounting system but I'm also very interested in the skateboard motor option if they are quiet and can generate enough torque to climb hills. I don't care much about speed on flat roads but my old legs just don't have the stamina I had in my youth to mash long steep hills and I'm hoping a friction drive set-up can give me the quiet boost I'm looking for to maintain at least a 7 MPH (11 Km/Hr) pace without the need to hop off the bike and walk. Are there any others that are just looking for a quiet low-speed/high torque hill-booster option? Thanks.
 
I have been having thoughts of a dual motor setup, with double the contact area, and a nice amount of engagement could be had. A reliable 1500w would be nice. Not so stealth but could work for those that need a bit more grip and grunt.
 
I set up my test station and thanks to Kepler and Payder I was successfully able hook-up the hall throttle to VESC.
Thank you guys.
I had one little problem. My motor was applying the brake after I released the throttle. Not good for riding.
I couldn't find anything about how to stop it from happening, and that was driving me crazy. Finally I learned something new.
VESC will apply brake while in DUTY CYCLE which is good for testing. I still don't know how to change that, but...
In CURRENT mode brake is not applied unless you configure it to do so.
 
Ecyclist said:
I set up my test station and thanks to Kepler and Payder I was successfully able hook-up the hall throttle to VESC.
Thank you guys.
I had one little problem. My motor was applying the brake after I released the throttle. Not good for riding.
I couldn't find anything about how to stop it from happening, and that was driving me crazy. Finally I learned something new.
VESC will apply brake while in DUTY CYCLE which is good for testing. I still don't know how to change that, but...
In CURRENT mode brake is not applied unless you configure it to do so.


Ecyclist, I might not be recalling correctly but you need to change the setting for 'Motor min (regen)' value towards the positive (or zero) (it's in 'Motor Configuration-MOTOR). Also, 'Batt min (regen)' value may need increasing to positive also.
 
Kepler said:
mechhead said:
It is a very fine balance with tyre pressure between too little and motor slip and too much and motor slip, too little and there is inadequate pressure against the motor can and too much and there is too little tread wrap surface area against the tyre. The best i can get is around 800 watts with a slick 2"x26 tire. i think the closer to over centre the lever angle of the motor the better the partial power performance is bit the less deeply it bites in to the tyre and the less possible tread wrap you will get. i have not tried grip tape on the motor yet i rekon this could give higher power levels but would shread the tire fast. I think Im doing well to get 800w into the tire as Kepler says he only gets around 400 to 500 max (Kepler please correct me if im wrong ) but his bike is a racer with skinny tires maybe a fatter 2.25 or 2.5" would get more power

The optimum tire bite is if you draw an imaginary line from the pivot point on the swing arm, through the centre of your motor, and through your wheel hub. I tend to set them up with a few degrees less with lower powered systems I think you get a smoother action this way. I agree 800W is about the limit. But thats not the design intent. Its all about ultra light weight which means small battery which in turn means low power if you want to get any reasonable range out the pack.

I think the sweet spot in 250 Whr battery and a switchable between 200W and 400W.

With grip tape using a 6374 motor and a hard compound 2" tire, I have run 1500W without any slip. It worked fine but I really dont see the point.

How come you say you don't really see the point of 1500w compared to 200/400w? Put it another way, could you explain to me the philosophy of use behind this statement?
 
hey Kepler, I have not posted since I bought your prototype. life kind of got in the way I guess. I will post a few pics once I get everything looking at least presentable.
I just took my second ride tonight. test ride I will say. the first one was truly out of control. I am riding with your mount a 6354 motor and a 90 amp speed control with a servo tester mounted to my handlebars. quite a site riding on 23mm road tires. so on ride one i pressed my servo tester to center and I felt like that scene from road warrior when Mel fires up the supercharger. then did a couple runs and got the hang of it. a little later I almost caught up with an unexpected street bike. granted he was in the neighborhood but always zooms to the stop sign kind of thing. So after that I put my bike away before I either wrecked or burned something up. motor tires and speed control were all pretty warm.
Tonight I took out for a second ride after knowing the potential of the drive and rode a bit longer with I would say a 1/4 to 1/3 of the servo tester. Amazing pull!!! I am running a 6S 4 amp Zippy battery at the moment. I think a 4S would probably do it.
initial tests: controller barely warm, battery not at all motor the warmest but I really think it is due to my oddball throttle setup via servo tester. I need to do a mod and maybe learn to program the castle controller for less ramp up or something.
Anyhow great invention you have there. very inspirational for home builders. cant wait to refine and tune it for a fantastic commuter to work.
 
Great to hear you got the bike up and running and are enjoying the experience. This is a reason why I have persevered with these drives for so many years. Running the drive with an RC controller certainly will give you some decent performance on light bike. And you can tame down a Castle Creations controller though its software for a more refined riding experience. However if you really want a refined ride, do do yourself a favour and get a Vesc. Run it on FOC with a 2 speed button, and you will never look back, trust me.

Look forward to seeing some pictures in the near future.
 
Driveless said:
Kepler said:
mechhead said:
It is a very fine balance with tyre pressure between too little and motor slip and too much and motor slip, too little and there is inadequate pressure against the motor can and too much and there is too little tread wrap surface area against the tyre. The best i can get is around 800 watts with a slick 2"x26 tire. i think the closer to over centre the lever angle of the motor the better the partial power performance is bit the less deeply it bites in to the tyre and the less possible tread wrap you will get. i have not tried grip tape on the motor yet i rekon this could give higher power levels but would shread the tire fast. I think Im doing well to get 800w into the tire as Kepler says he only gets around 400 to 500 max (Kepler please correct me if im wrong ) but his bike is a racer with skinny tires maybe a fatter 2.25 or 2.5" would get more power

The optimum tire bite is if you draw an imaginary line from the pivot point on the swing arm, through the centre of your motor, and through your wheel hub. I tend to set them up with a few degrees less with lower powered systems I think you get a smoother action this way. I agree 800W is about the limit. But thats not the design intent. Its all about ultra light weight which means small battery which in turn means low power if you want to get any reasonable range out the pack.

I think the sweet spot in 250 Whr battery and a switchable between 200W and 400W.

With grip tape using a 6374 motor and a hard compound 2" tire, I have run 1500W without any slip. It worked fine but I really dont see the point.

How come you say you don't really see the point of 1500w compared to 200/400w? Put it another way, could you explain to me the philosophy of use behind this statement?

The drive is designed to keep the bike light weight so it still rides like a completely normal bike. If you want to run 1500W, then you need a big battery to suit. The drive is not designed for 1500W. If this is the power number you are after, I would not recommend this drive

To be clear, I see the point of 1500W plus for performance ebike applications and i get a real buzz out of my 6kW Beta every time I ride it. However my light weight friction drive road bike is still my weapon of choice and does the most miles by far out of all the bikes in my fleet.
 
My Trek Domane 5.9 road bike running a 63-54 236kv Turnigy motor, Vesc and 2 button interface continues to serve me well and clocks up around 150km a week. reliability has been excellent with the only maintenance needed being a quick spray of parts cleaner and a drop of Teflon oil on the swing-arm pivot once a month or after riding in wet conditions.

In an effort to take the drive to the next level, I have decided to try a high end Scorpion RC motor. I have used Scorpion motors on my RC helicopters for many years and have always been very impressed with their power to weight ratio and excellent quality. Of course quality and performance comes at a cost with this motor being more then double the cost of a Hobby King motor with similar performance. However, the more I use this drive system, the more I feel it deserves a high end motor to really complement the the rest of the system.

One of the great features of Scorpion motors is that they can handle really high operating temperatures. They also are designed to cool really well which means a smaller motor can be used that will still provide the required power output. With this in mind I have selected the smallest and lightest motor that i have ever used on a friction drive. Selected motor is a SII 4025 320kv. Diameter of the motor is 49mm which has allowed me to go to a 320kv wind. Weight of the motor is 322 grams yet it is rated at 2000W continuous. Rule of thumb is halve this for an ebike application so considering I and only using 400W peaks, this motor wont have any issues with with the power asked of it, it will be more about the available torque and what sort of noise it makes with the Vesc on FOC.

Anyway, here are a few picture of the motor for your viewing pleasure :)
 

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I’ve managed to run the three cables from a saddlebag-mounted battery through my aluminium seat post and seat tube to get the 'stealthy' bike set-up. I did this by using thinner 12AWG PTFE wire around the inside of BB Shell and out through a 10mm hole in its base. I added an eccentric BB to shift the hollowtech spindle forwards and create 3-4mm extra clearance for the wires around the back of the shell. PTFE wire is pretty stiff and tends to stay where you put it - but for extra security, to prevent the wires slipping to rub against the spindle, I made a spring clip from 1mm steel wire. This pushes back into the two internal chain-stay holes inside the BB shell and clips the wires into position. Ideally, the spindle should have a static thin-wall tube around it to completely isolate it from the wiring - but that’s a bit beyond my abilities at the moment.

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An update on the testing of the Scorpion 4025 320kv motor. I have run it for around 60km and have been mostly pleased with its overall performance. At close to half the weight and size of the Turnigy 6354 motor is surprisingly close in performance with the 6354 having marginally more torque. Noise wise, at high speed sound levels are quite similar however at low speeds, the Scorpion motor is around 50% noisier then the larger Turnigy motor. Although not ideal, its not a deal breaker and warren's further efforts to see if noise can be reduced. My thoughts are to try a motor cover with sound deadening material attached to see if this approach can reduce the overall noise to a point whereby it is no longer audible. This would be my holy grail. This approach may introduce a whole new set of issues but i think it is worth experimenting with. I have purchased the aluminium bar stock and will start work on the motor cover this week.
 

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