Friction Drive New Kepler carbon build

[Samd]

18650 GA cells?

 

[Allex]

GA yes or 30Q as a high power alternative.

 

[oatnet]

I am looking at my options in relation to a smaller more compact pack.

Hey Kep I noticed you are using the modular cell holders that are 20mm per cell. I'm making a 2p14s pack from Samsung 30Q's for a BBS build, and I used these fixed-configuration cell holders I found on Aliexpress that are smaller, about 19mm per cell, plus you don't have unused joiner tabs sticking out the side. It adds up to a pretty good difference, but I don't know if it is significant enough to get you where you want to be. Although they are fixed configuration they offer a wide range of sizes, and could be cut down to fit irregular/curved surfaces. Also note the through-holes between each cell might offer some ventilation, or an alternate path for balance wires, or through-bolts for alternative mounting methods. The fixed-config also has less flex to it, making for a sturdier pack.





Edit:

Link to the 4*7 holder (133mm x 76mm)
http://www.aliexpress.com/item/18650-lithium-battery-holder-4-7-28-holes-for-24v-li-ion-battery-pack-4P7S-18650/32364649756.html

Link to the Custom nickel strip that fits the holders:
http://www.aliexpress.com/item/18650-li-ion-battery-pure-nickel-strip-3P2S-4P2S-5P2S-nickel-belt-lithium-battery-nickel-plate/32366776392.html

-JD

 

[Kepler]

I like it. The 20mm holders are a pain to assemble and take as much time to fit together as the actual spot welding.

I will get hold of some of these to try. Thanks for the heads up.

 

[LikeToRideMyBike]

These holders look very simple and easy. I'm interested in this one: http://www.aliexpress.com/item/Free-Shipping-4-13-52-holes-18650-battery-holder-integrated-Used-for-4P13S-48V-10ah-li/32426925172.html?spm=2114.10010108.100010.22.YFKlPq

I assume that soldering is required?..

 

[Kepler]

A bit of an update. Drive is going strong and clocking up plenty of km's. Got a good feel for the true consumption of the drive now that I have used the drive over a variety of rides. Bottom line is my 7S3P pack 25R 18650 pack is good for 60 minutes of full time assist which for most rides really is overkill.

So I have been experimenting with some modular pack arrangements so I can tailor the amount of battery I carry to suit the planned ride. I have made up 2 x 7S1P packs that can be used individually or stacked together allowing me to use one pack and swap over to the second pack if I need to. The drive pulls around 8 amps which is no problems for 25R's even in a 1P config.







Also gave the bike a hard run up an iconic hill climb called the 1:20 down here in in Melbourne. Drive performed flawlessly and allowed me to log a very respectable Strava time of 15 minutes 18 seconds. That was just over 6 minutes improvment of my previous best unassisted time. I have of course deleted the climb off Strava now.

 

[Decagrog]

This is my first post but I've lurked the forum for friction drive stuff for some months
Really like your minimalist project Kepler, I've intention to try to build something similar for my foldable Tern so I'll surely follow any evolution!
Anyway that 200kv motor is pretty light, what model/brand is?

 

[Kepler]

Thanks Decagrog and welcome to the forum.

I bought 10 of these from this supplier http://maytech.en.alibaba.com/produ...unner_motor_For_electric_rc_jet_airplane.html My stock is all gone now though.

Keep in mind the 50mm motor is a bit light on if you intend to use the drive continuously. Works really well in an assist role as with this bike though. A 63-74 is a better choice if you have the room. Also much easier finding a low kv motor when you go the 63mm.

 

[Decagrog]

Thanks for the fast reply Kepler,

Yep my use will be primary just for assist, I live in a place with a lot of inclines and hills but I'm pretty accustomed to climbing and weight just 58kg
I'm not searching for top speed so I'll start with a 6s lipo since I already have one along with a 2s-6s charger, then maybe later I'll build a 7s li-ion batterypack from 18650 cells like yours.

I don't have much clearance on the bike so I would like to opt for a compact outrunner, I've checked the Maytech that you linked but seems hard to find place online where to buy a single unit, on alternative I was thinking about a KD 5320 http://www.hobbyking.com/hobbyking/store/__51869__KD_53_20_Brushless_Outrunner_195KV.html is a 56mm in diameter but actually is in backorder... I hope will return back to stock soon

Anyway I don't want to bring my issues in your thread, I'll eventually start a new one after thinking a bit more about the entire setup

 

[Kepler]

I have been using this bike a couple of times a week as a commuter and am really pleased with its overall performance. Only drawback has been that the riding position is fairly aggressive with the bullhorn bars. Although I really like the way they look, they have proven to be less than practical for everyday use.

Decided to see how the bike performs with flat bars and rapid fire shifters. Conversion was done today and a quick 10km test ride was very promising. Riding position felt much more comfortable and the front derailleur shifter that operates the friction drive made it really smooth and easy to activate the drive. Bit sad to have removed the bullhorn bars but I think the bike is going to be a better bike for it. Weight hasn't changed with the flat bar config and is probably slightly lighter as the main components are carbon.

 

[Raged]

Drop bars is where it's at. There's some cheapo microshift shifters around from cyclingdeal. I havent used them yet, but its an option for my next gravel grinder/cyclocross.

 

[Kepler]

I know where you are coming from but the geometry of this bike with drops really bends you over. Makes for an uncomfortable commuter. The Flat bar setup makes the most practical sense with this bike.

With regards to the Microshift shifters for drop bars, I did look at this. Unfortunately they do not have hidden cables and as such make the bike look very 90's. 5800 series 105's are about the cheapest you can buy with hidden cables but then you are forced to go 11 speed. Costs quickly add up. I am using a 9 speed on this bike which is all it needs with the assist setup. With Microshift rapid fire shifters on flat bars, this has really helped keep cost down.

Total agree that drop bars look the goods but i think the flat bar setup isn't too bad either.

 

[Raged]

I know where you are coming from but the geometry of this bike with drops really bends you over. Makes for an uncomfortable commuter. The Flat bar setup makes the most practical sense with this bike.

With regards to the Microshift shifters for drop bars, I did look at this. Unfortunately they do not have hidden cables and as such make the bike look very 90's. 5800 series 105's are about the cheapest you can buy with hidden cables but then you are forced to go 11 speed. Costs quickly add up. I am using a 9 speed on this bike which is all it needs with the assist setup. With Microshift rapid fire shifters on flat bars, this has really helped keep cost down.

Total agree that drop bars look the goods but i think the flat bar setup isn't too bad either.

Im not convinced on the hidden cable thing as they say shifts arent as crisp due to cable bends. It just seems like the design precursor for di2. 9 speed is the happy zone for cable shifting because indexing is the same for mtb/road, so you can still mix and match shifters/derailleurs and cassettes. I run sora 3500 because its cheapish (on special at wiggle sometimes, but still looking at $140ish for the STI levers) and my wrists fatigue over long distances with flatbar while trying to be aero. Its personal preference.

Had to double take on your bike geometry... and yeah... my back is pinging just looking at it! Im gonna stick to 29ers =)

 

[Mikebergy]

5800 series 105's are about the cheapest you can buy with hidden cables but then you are forced to go 11 speed.

You can find 10 speed all over the place with hidden cables. I run Sram Apex on my roadie, and it is dirt cheap, and 10-speed.

 

[Raged]

5800 series 105's are about the cheapest you can buy with hidden cables but then you are forced to go 11 speed.

You can find 10 speed all over the place with hidden cables. I run Sram Apex on my roadie, and it is dirt cheap, and 10-speed.

Does SRAM shift indexing work across both disciplines? Eg. SRAM 10 speed STI road shifter with mtb rear derailleur and MTB cassette for bigger gear spread?

 

[Mikebergy]

5800 series 105's are about the cheapest you can buy with hidden cables but then you are forced to go 11 speed.

You can find 10 speed all over the place with hidden cables. I run Sram Apex on my roadie, and it is dirt cheap, and 10-speed.

I believe all their 10-speed stuff is indexed the same, but I've not needed to worry about it, as the Apex long cage is dirt cheap and supports up to an 11-32 cassette, which is plenty of range for just about anything.

Does SRAM shift indexing work across both disciplines? Eg. SRAM 10 speed STI road shifter with mtb rear derailleur and MTB cassette for bigger gear spread?

 

[Mikebergy]

Does SRAM shift indexing work across both disciplines? Eg. SRAM 10 speed STI road shifter with mtb rear derailleur and MTB cassette for bigger gear spread?

I believe all their 10-speed stuff is indexed the same, but I've not needed to worry about it, as the Apex long cage is dirt cheap and supports up to an 11-32 road cassette, which is plenty of range for just about anything.
Edit: I have checked online, and it looks like the SRAM XX components and all the 10-speed road components are compatible.

 

[Samd]

Clever move on the modular packs Kep.
I've been following a lot of Nobuo's pack builds and he's been doing away with the cell holders, opting for simply hotmelt bonding the cells together. Gonna give it a try.

Take care,
Sam

 

[Decagrog]

How did you manage to modify the KU65? I finally got mine from bms but is quite different (and with no printed labels on pcb :x ) from the KU63 on avdweb.nl blog

 

[John.Ser]

I just registered to post my first comment and thank Mr. Kepler for all the insight and motivation he's shared to build minimalist friction drive systems. I'm interested in adding a stealthy, low-speed friction drive to my 1983 Trek 720 as I just don't have the hill-climbing stamina I had in my youth. The long wheel base of these old touring frames provides plenty of room under the bottom bracket to accommodate a flat mounting plate with a possible quick release similar in concept to what "Add-E" does with their friction drive system. (Too bad their turn-key systems are so expensive and more complicated to comply with European regulations.) I'm just looking for a boost to climb steep hills so I look forward to further postings and I will also look into other design options developed by Adrian' and Michael@Engineerdog.com for more direction.

 

[Kepler]

Update:

As a flatbar commuter, this bike has been a reliable ride and clocked up around 2000km in this configuration. The rear tire is showing no abnormal wear from the drive and the tiny RC motor and KU65 controller have run without fault.

As much as the flatbar config makes sense as a commuter, this bike really deserves drop bars and as such I have been looking for a compromise that returns the bike to a true road bike but doesn't break my back with its aggressive riding position.

After a bit research, I found a set of compact drops and head stem with a 17deg rise. This has lifted the riding position nicely and given back the bike the look it deserves. Went with Shimano 105 5800 shifters and 11 speed 11-32 cassette. Stuck with a 44 tooth chainring on the front. The shifter for the front derailleur is still used for drive activation. Needed to change the pivot ratios to get the swing I needed for the drive to fully engage but this is now working nicely.

Also added PANASONIC 3500mAh 18650 cells in a 3P7S config for a very respectable 300 Whrs without any additional weight added to the bike. This gives me around 75 minutes of full time assist and a good 50km range without raising a sweat.

Looking forward to the next few months of riding especially with the weather now on the improve.

 

[ScooterMan101]

Kepler,

I want to go to a drop bar on my e-road bike , I presently have a straight MTB Carbon bar, with Flat Bar Road Shifters,
and it works fine with a thumb throttle , However My hands /palms get sore from just having one position.

( I already have a Specialized Stem that have different + / - Rises with inserts , the comp 17 degree Multi Stem )
so I can be comfortable .

I have sitting in a box, a Drop Bar, and Rival 10 speed Shifter/B. Levers , because, I know of ... No available
throttle that would work with a Drop Bar .
I tried to test a thumb throttle sitting it sideways on the drop bar but it would not work , too unnatural position with the thumb, and also because I also made the thumb throttle with no spring, ( I took it out of the housing , so that I can use it in cruise control mode. and it works great that way, not spring to make my thumb sore !

Hopefully you can design a Throttle, that is small enough to fit onto the brake lever , picture a vertical left and right click mouse pad that we have on our laptop computers.

make it small enough to be glued onto either the right or left brake lever ( road bike STI ) , with more speed in the up position, and lower speed on the lower position,
that way when you grab/pull in the mid to lower part of the Road Bike Brake Lever, you are also backing off the throttle .
Add to that for each click of the up or down button/pad, you increase or decrease the speed 1 kph, that way you can also have a cruise control. then when you need to slow down, you
are simultaneously slowing the bike down because the minus pad is in the lower position , and braking to cancel the cruise control. This would be done with your lower 2-4 finger , while speeding up will be
done using your first finger on the upper plus pad.
Hope I described this well enough .

 

[Raged]

Kepler,

I want to go to a drop bar on my e-road bike , I presently have a straight MTB Carbon bar, with Flat Bar Road Shifters,
and it works fine with a thumb throttle , However My hands /palms get sore from just having one position.

( I already have a Specialized Stem that have different + / - Rises with inserts , the comp 17 degree Multi Stem )
so I can be comfortable .

I have sitting in a box, a Drop Bar, and Rival 10 speed Shifter/B. Levers , because, I know of ... No available
throttle that would work with a Drop Bar .
I tried to test a thumb throttle sitting it sideways on the drop bar but it would not work , too unnatural position with the thumb, and also because I also made the thumb throttle with no spring, ( I took it out of the housing , so that I can use it in cruise control mode. and it works great that way, not spring to make my thumb sore !

Hopefully you can design a Throttle, that is small enough to fit onto the brake lever , picture a vertical left and right click mouse pad that we have on our laptop computers.

make it small enough to be glued onto either the right or left brake lever ( road bike STI ) , with more speed in the up position, and lower speed on the lower position,
that way when you grab/pull in the mid to lower part of the Road Bike Brake Lever, you are also backing off the throttle .
Add to that for each click of the up or down button/pad, you increase or decrease the speed 1 kph, that way you can also have a cruise control. then when you need to slow down, you
are simultaneously slowing the bike down because the minus pad is in the lower position , and braking to cancel the cruise control. This would be done with your lower 2-4 finger , while speeding up will be
done using your first finger on the upper plus pad.
Hope I described this well enough .

I'm pretty happy with my dropbar throttle setup, but the other "stealth" option was a voltage divider circuit for the throttle and 3 buttons you can place anywhere.

button 1 : 30%
button 2 : 70%
button 3 : 100%

The standard throtte is a hall sensor that changes voltage depending on throttle position. Should be easy to fab up with about $10 worth of parts.

 

[g725s]

this build is so stealthily done you could have sold one of these to Lance Armstrong :wink:

 

[ElementX]

Awesome job on this project! This was an amazing build.