Kepler Friction drive comes of age.

[JTL]

Kepler, I have been following this thread for a while and also have an observation. If you want this FD to really take off I think it needs to be in kit form or at least greatly simplified. I am past the point of wanting to program things or do a McGyver to get the bike running. At least include a controller, throttle and what ever it takes to lift the motor to the tire, maybe purchasing the motor separately is not a big issue. If I am alone in this thinking forgive my ignorance. You are obviously doing a great job so far.
John

 

[Pranav.ptl]

Thanks for battery info.. is there a distinct advantage on a 6s to a 7s or an 8s? like charging kits etc etc? also did u install a BMS for cut off etc to the battery pack?

also any possibility on installing a PAS to your idea? and i might use an rc esc as cant go about soldering an ebike esc (solely due to no tech no how)

 

[Stu Summer]

John had a similar thought to mine. If you don't want to go into sales (except the swing arm mechanism), then a webpage that gets updated with successful combinations of batteries, controllers, engagement hardware and motors and their sources. Very impressive work!

 

[tomjasz]

Good land, This thread alone has most of the needed information, and given the number of diffent bikes and geometries there's always some Mcgyver to kit building. Or buy one of those $1000 kickstarter friction drives.

Reminds me of the guy pissed off when he couldn't get 20AH in a Dolphin, it just takes some reading and thought to sort.

 

[JTL]

Good land, This thread alone has most of the needed information, and given the number of diffent bikes and geometries there's always some Mcgyver to kit building. Or buy one of those $1000 kickstarter friction drives.

Reminds me of the guy pissed off when he couldn't get 20AH in a Dolphin, it just takes some reading and thought to sort.

Relax and take in a little fresh air. Some of us just want a simpler solution and you can keep your negative comparisons to yourself.

 

[Kepler]

I will consolidate motors and controllers that I have tested or think would be suitable and amend the lead post with this info in the near future.

 

[Kepler]

Kepler, I have been following this thread for a while and also have an observation. If you want this FD to really take off I think it needs to be in kit form or at least greatly simplified. I am past the point of wanting to program things or do a McGyver to get the bike running. At least include a controller, throttle and what ever it takes to lift the motor to the tire, maybe purchasing the motor separately is not a big issue. If I am alone in this thinking forgive my ignorance. You are obviously doing a great job so far.
John

I have certainly considered this with the controller and throttle being part of the package as a minimum. I know this would open up the market much further. Baby steps first though. Once the drive mechanics design is consolidated, I will look at this as the next step in the evolution.

 

[Stu Summer]

Thanks so much, Kepler!

 

[mhaskell]

I was amazing at the difference in sound the foc control made in vedders videos.
I am going to order the vesc at the link below, what do you think kepler?
https://www.vandaelectronics.com/products/vesc-motor-controller-custom-cables-and-connectors

 

[Kepler]

I think it will be a great fit for the drive. I haven't tested one yet but I do have one order also. As I said on a number of occasions, get the noise down and we have a game changer.

As you can see from my video, performance and usability are all there. Just need to tick off that last thing.

 

[MrDude_1]

So that's a fail however look what just turned up on my desk. Skateboard hub motor. Should be interesting.

Where did you get that from?!

I really want a off-the-shelf-non-project-it-just-works hubmotor skateboard, but I cant justify the cost.... plus I like my dropdeck longboards... so a cheap hubmotor that works is exactly what I am looking for... no belts.

 

[qouixster]

Amazing work
thanx for this !
keep it up !!

 

[ScooterMan101]

Is that red wire at the bottom of the controller ( 3 red wires together with a 3 pin connector )
for a Throttle ?

I was amazing at the difference in sound the foc control made in vedders videos.
I am going to order the vesc at the link below, what do you think kepler?
https://www.vandaelectronics.com/products/vesc-motor-controller-custom-cables-and-connectors

 

[ScooterMan101]

+ 1
Looking forward to a throttle with cruise , on the hoods, brake/shift lever.
and
A mount system for BB30 / BB 86 / BB92 / Pressfit , bottom bracket bikes, which is the majorty of the Road Bikes sold today and the last couple of years now.

Amazing work
thanx for this !
keep it up !!

 

[Kepler]

So that's a fail however look what just turned up on my desk. Skateboard hub motor. Should be interesting.

Where did you get that from?!

I really want a off-the-shelf-non-project-it-just-works hubmotor skateboard, but I cant justify the cost.... plus I like my dropdeck longboards... so a cheap hubmotor that works is exactly what I am looking for... no belts.

Looks like the seller has no longer stocks the motor. Not a good sign. Anyway. I will test it and see how it goes.

 

[Kepler]

+ 1
Looking forward to a throttle with cruise , on the hoods, brake/shift lever.
and
A mount system for BB30 / BB 86 / BB92 / Pressfit , bottom bracket bikes, which is the majorty of the Road Bikes sold today and the last couple of years now.

Amazing work
thanx for this !
keep it up !!

As much as i would like to make the drive fit the BB's you have listed, the drive at this stage is designed for screw in bearing holders as fitted to English BB68 bottom brackets. There are conversion kits available to convert BB30 / BB 86 / BB92 / Pressfit to screw in cups however I am not sure what they do to the chainline.

Interestingly, the big manufacturer's are going back to screw in bearing cups on their medium range road bikes. check out the latest range of Specialized bikes. https://www.specialized.com/au/en-au/115487 this bike has screw in bearing cups. You are Looking at my next friction drive project.

This means my current test bike with my latest drive is going up for sale at a bargain price

 

[ScooterMan101]

Interesting that that mid level Roubaix is using the BSA Threaded BB ,
Perhaps that way Specialized does not have to pay royalties to whoever has the BB30 Patent .
On that model of Roubaix they are using Praxis Works Cranks, so perhaps better pricing on the BB and Crankset as an OEM setup. Also Praxis Works is located only about 50 miles away from Specialized so they are going with a Local Company, ( Think Globally, Buy Locally ).

In regards to Chain Line when using an adapter that fits into a BB 30 Frame Shell , that will allow you to use a threaded BB, The Chain Line should be roughly the same. When you look at a BB30 crankset, and a Shimano Hollowtec II Crankset,
one difference is that the Shimano has a longer spindle , even though they both fit into a 68mm wide shell. The Shimano has the spindle go further into the Crank where the Chainrings are, there is space in there to fit the chainrings around the outside of the outer bearings.
Also on the note of Adapters BB30-BSA Threaded, Mechanics that I have asked have said that the only one that works even halfway decently is the Praxis Works one. the others will rotate in the BB Shell, they have to be press fit into the shell and they do not grab onto / bite into the shell so they wind up rotating a little .
So We ( all who have BB30 or other pressfit Bearing Shells on our Road Bikes / and a few MTB's , would have to go through the following costs to get your Friction Drive to work/fit.

Praxis Works BB30-BSA Adapt $ 89 plus Tax, ( Edit : $ 75 plus tax and shipping , and some antisize so a little over $ 100 )
then
A Shimano Hollowtec II or simular Crankset plus Tax - $ 85 - $ 200 +
so
nearly $ 200-$ 300 to get it to work.

At those prices , I will have to wait until you develop a way to mount the Friction Drive on BB30 Bikes.
I do have a Full Suspension Frame I have not yet built up that has the BSA Threaded BB, but how would the Friction Drive follow the Wheel/Tire while it is doing its job ? Moving at an arc of up and forward .
I would be interested if that can be accomplished , and it would go up very steep % of Grades for long distance climbs. like up the Mountain in Bright , VC.
the F.S frame I have is a single pivot design.

As much as i would like to make the drive fit the BB's you have listed, the drive at this stage is designed for screw in bearing holders as fitted to English BB68 bottom brackets. There are conversion kits available to convert BB30 / BB 86 / BB92 / Pressfit to screw in cups however I am not sure what they do to the chainline.

Interestingly, the big manufacturer's are going back to screw in bearing cups on their medium range road bikes. check out the latest range of Specialized bikes. https://www.specialized.com/au/en-au/115487 this bike has screw in bearing cups. You are Looking at my next friction drive project.

This means my current test bike with my latest drive is going up for sale at a bargain price

 

[Kepler]

Based on some feedback from one of my beta testers, it was found the bolt pattern of a SK3 63mm motor didn't fit the swing arm. Also I have found that with the heavier 63mm motor it is important to secure the anti rotation arm more firmly. To aid with this, I have slotted the end of the anti rotation arm so the cable tie can hold it more firmly.

Should have the new parts back from the laser cutters next week.

 

[Pranav.ptl]

Looks awesome! Hoping to be able to get it soon!

 

[Pranav.ptl]

Could you also give us a link to your 18650 source?

 

[ScooterMan101]

Depending on where you live, you could have someone in your country that could build you a 7s pack .
Where do you live ?
If not , ask one the big DIY E-Bike Conponent vendors to make you a 7s pack.

Or you could go with hobby lipo's , which in this application, would be just one 6 s pack and charger, or buy two 6 s packs for longer range. It looks like this system is/will be using very little watts per hour.

 

[Pranav.ptl]

Thanks.. Would I be correct in assuming that an 18650 pack would be safer for a novice (considering most ready to go kits use them). A lot of confusing articles around..

Also should I be considering any other safety features?

 

[ScooterMan101]

Yes , Absolutely .
The only reason I mention Hobby Lipo's is because for this Friction Drive Motor that Kepler is using / he says the battery choices are 7s 18650 Li-Ion, or , 6s Hobby Lipo packs .

There are plenty of RC Hobby packs and chargers in the 6s configuration, but now days the newer 18650 Li-ion cells weigh about the same. and have the benefit of easier , and less complicated charging.
And from what it looks like, even though Kepler has not stated/or is somewhere back in the thread somewhere, ... the amps he is pulling from the battery pack my guess you do not, need the higher amp draw that the Hobby Lipo's excel at given you get a 20c or higher lipo pack.
Would like to hear what amps he is running this latest Friction Drive at.

Depending on where you live, there is someone who can make a custom 7s pack for you.
3 p would be the minimum I would have made, more like 4p or better yet 5 p for your longer weekend rides.

There is no / or at least very little money in making such a small 7s 18650 cell Li-Ion pack.
And the hassles of shipping to different countries, So my guess is that Kepler will concentrate on the mounting system , controller, and just a few other items of the system.
Like,
Hopefully a small Throttle ( with cruise or that has some friction to it so as to have cruise , that fits onto the Hoods or Brake Levers that Road Bikes Use.

Thanks.. Would I be correct in assuming that an 18650 pack would be safer for a novice (considering most ready to go kits use them). A lot of confusing articles around..

Also should I be considering any other safety features?

 

[Pranav.ptl]

Thanks a ton! What i need to do is indeed clear to me!

Kepler we would love to hear your amp draw through the extensive tests u have carried out.

 

[Kepler]

I am using a KU65 controller at the moment which is a 14A controller. On 7S 18650, it peaks at about 350W.

The main reason why I am not going over 7S even though a KU65 can handle 10S (36V) is that ebike controllers have very low electrical RPM capabilities. As soon as you go over the electrical RPM threshold of the controller, the motor stops. Its a balancing act with cheap ebike controllers and RC style motors. If you use a 140kv motor, then you could run 10S 36V. However, 200kV to 280kv motors are easy to get and as such 7S 18650 or 6S LiPo is a good fit as it just keeps you under the electrical threshold of the controller. Worth noting that if free spinning, you still might go over the threshold, however under load its not a problem.

The same goes with any of the cheap 6S ebike controllers like the S06P. However, RC controllers dont have the same electrical RPM issues. They typically dont have current limiting either which can be a problem in an bike application. The vesc skateboard controller does have current limiting and it is a true FOC sinewave controller. This should mean quieter operation and a fully programmable current limit to suit you needs. I can't wait to get mine and start testing.

In regards to battery capacity, with a 14A controller 250 Whrs is a good number as it gives you about an hour of full time assist and only weighs just over 1kg. This is a 7S3P 18650 pack using 3.5ah cells. With my road bike, used constantly during the ride, I get about 30km with this size pack. Used for assist when needed, I arrive home fresh even after an 80km ride.

There is no / or at least very little money in making such a small 7s 18650 cell Li-Ion pack.
And the hassles of shipping to different countries, So my guess is that Kepler will concentrate on the mounting system , controller, and just a few other items of the system.
Like,

100% correct ScooterMan. I will look at selling the drive complete with motor and electronics package once I find the best combination, leaving only the battery to be sourced separately. The way I see it, I dont think people should shy away from LiPo when the pack is quite small. There are millions of RC pilots who use the same size 6S pack in RC planes, helicopters, and drones. This sector is smart enough to minimise risk by balance charging and storing the packs in LiPo bags. I am sure the ebike community is smart enough to do the same .