New build. Full carbon 29er weight weenie Super Commuter.

Recent experience's with the some nice quality commercial e-bikes got me fired up to look at building a low powered but high speed commuter / flatbar road bike that would be hard pressed to even be recognized as an e-bike by the general public using the local bike paths.

As a bit of back ground, after having a quick test of an e-motion Jumper just around a car park, it felt so impressive that I seriously considered purchasing one. So the next move was to go visit the suppliers and take the bike for a proper test ride. First impressions were very good with some nice assist. However, the bike was limited to 25kph assisted as per Aust / Euro regs. So to ride the bike at a decent speed, you needed to work twice as hard because effectively the motor assist was doing nothing for you and you were now trying to push a 20kg bike at a decent speed.

In addition to e-biking, I have to admit I am a closet Lycra and average about 100km a week on my carbon road bike. Every time I get on this bike I am always blown away by the efficiency of these modern high performance road bikes. I have no doubt I could average a better speed on my road bike then I could on Aust. reg compliant e-bike.

So with this in mind, I figured it was time to blend the best of both worlds and build a e-bike that free rides as well as a high spec road bike but at the same time had e-assist capable of a sustained 50kph under favorable road conditions.

The process of gathering components has now started. Cornerstone of this build is a full carbon 29er frame complete with rigid carbon forks. I decided to go down the path of a 29er because of my height and the fact that it is a mountain bike frame and as such provides a bit of extra strength. Total weight of frame and forks comes to 1.8kg. Nice start. 8)



View attachment 1

White Industries disc brake compatible hubs have been laced into 36 spoke 700C rims for strength and fitted with some nice 203mm floating discs back and front. Magura M2 Hydros will be used for some serious stopping power.



More detail on how this bike will be powered to come.

Kepler said:

More detail on how this bike will be powered to come.

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Friction drive?

Great thread. Look forward to seeing your build. I am firmly in both camps as a moto head and lycra wearing weight weeny roadie. Been so for 40 plus years and make no apologies about it.

Would love to see / ride sub thirty pounds 2+kw. Mid / large size astro motor/ and back pack battery?

Cool, another 29er ... should be pretty awesome with those components and your build skills.

Magura make an ebike cut out hydro, something to think about if you need regen

Kepler said:

I have to admit I am a closet Lycra

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Ah, this brings balance to the force - lycras clad roadie one day, 12kw stealth bomber the next :lol:

This sounds like a cool build, I look forward to seeing how it turns out.
I rode what I think was a decent sort of road bike a while back and you're right, the rolling efficiency difference is huge. It's almost like they pedal themselves. Atleast on the flat!

I'm not up on the carbon scene but how strong are those front forks in regards to braking forces? I've heard of a few fork failures (even motos snapping when doing stoppies) so wondering how they'll hold up with the strong forces that would come from pulling up hard with strong hydros ?
For riding on the the road with homocidal drivers (intentional or not!) they're a must in my book but it seems strong brakes are often overlooked on road type bikes (perhaps due to them counting every gram)

The bike is coming together well with the majority of the rolling frame assembled. As it sits at the moment, it has just hit 7.5kg. Still need to add bottom bracket, crank and chain so it looks like around 8kg before I start adding electrics.







I have configured the bike for a comfortable upright riding position and gone with 700C x 35 road tires for some added cushioning and good puncture resistance (in comparison to a normal road bike anyway)

Few minor problems I have run into.

I needed to go down to 180mm rear disc to clear the chain stay. Originally had a 203mm selected for the back.

I wanted to fit a road bike chain ring with 50 plus tooth count for a comfortable high speed cadence. Again issues with chain stay clearances. Being a mountainbike frame, it is designed for up to a 46tooth chainring and also the the large chainring is naturally spaced out by the 2 other chain rings normally on the crank set. To get around this this I will fit a Schlumpf bottom bracket with a 42 tooth chain ring. This fits nicely on the bike.

So now to the power plant.
Well Full-throttle was right about the friction drive. For the bike to be a true weight weeny, friction drive really was my only choice. However, I want this to be a cut above any fiction drive attempted so far.

This drive will not be about high power but more about seamless integration. Power wise, it will come close to fitting into the Aust Legal limit under most riding situations. However it will be capable of pumping out 1000W when it needs too and of course it wont be speed limited.

My aim is to use to the new CA3 with PAS to control the ESC. I think this may be a first for an RC style drive system to be used in conjunction with a PAS so it will be interesting to see how it goes.

On a previous build, I experimented with the friction drive mounted under the bottom bracket. Made for a super stealthy install and worked quite well.



This build will follow a similar theme however mounting of the drive is much more of challenge due to the carbon construction of the frame. Obviously there is no drilling of mounting hole in this sort of frame. I also need to be mindful of using clamp mounts as carbon frames done like crush loads on them. Anyway I think I have it worked out so more to follow on this part of the build.

Motor wise, I will start off with some cheap standard Hobby King motors on 6S to get everything tested and running correctly but the plan is to go with a high end Scorpion RC motor and HV ESC.



View attachment 3

Also looking to run 10S of various ah capacities. I really want to limit battery weight to around 1.5kg so as to keep the total bike weight to around the 10kg mark ready to ride. Great thing about this sort of bike is that running out of battery is a non event with the bike riding similar to a road bike for getting you home.

Excellent!

I'm looking at what a viable Panasonic 18650 based battery solution for this bike might be like.

So the requirements for capacity are? ~5Ah?

Configuration is 10S, most current draw would be 5/8A with 25A burst.

That is using Hub motor logic and I'm unsure how RC drives draw variable load power on flats, does it hammer current?
I remember adrians unit has a button that engages FT.

With your PAS system will you be going the 6/12 magnet route or going for a BB solution (is that viable)?

Yep that is about right on all accounts. I did a heap of testing back to back with an RC friction drive verus a bafang geared hub. basically they we very similar in relation to economy with the friction drive winning out on lightness and stealth look (but not sound ) where the geared hub won out with better rideability.

In relation to the PAS, I would love to try a Thun bottom bracket but unfortunately I also need the Schlumpf. So it looks like I be going with a 12 magnet PAS. I am hoping the the New CA3 will give me a few extra tuning options for the PAS above what you get out of a stock ebike controller.

Will be interested to see what you come up with the Panasonic 18650 batteries. I think it will be difficult to beat LiPo though for this type of build.

Kepler I like your idea. I have just come back from Adelaide with my bike. Flat bar road bike 14 kilos over the scales.

Would be just nice to have a 8 kilo flat bar road bike to ride to work but its normally the head winds that kill me not the distance. This would be when the electric assist comes in handy.

Looking forward to the rest of your thread.

but what does chalo think?

Oooo. Can't wait to see this one come together. Should be a ripper.

For the ESC, if you are planning on tackling the hills, rather than just the usual commute type stuff, you may want to check out one of the YEP ESC from hobbyking, to make the most of that 1000w. It appears to be a rip off of a previous generation YGE ESC, and has synchronous rectification, so should be much cooler at partial throttle.

As for batteries, check out the 18650 cells. They beat the RC LiPo on energy density, and for <1000w should still handle the current draw for a typical ebike sized pack.

Kepler said:

This build will follow a similar theme however mounting of the drive is much more of challenge due to the carbon construction of the frame. Obviously there is no drilling of mounting hole in this sort of frame. I also need to be mindful of using clamp mounts as carbon frames done like crush loads on them. Anyway I think I have it worked out so more to follow on this part of the build.

Click to expand...

BB bracket?

t3sla said:

I remember adrians unit has a button that engages FT.

Click to expand...

My drive has a PID loop controlling power to a preset limit, so not your typical RC full throttle. The CA v3 does a very similar thing, so you should be able to set it up to be gentle if you like.

t3sla said:

I'm looking at what a viable Panasonic 18650 based battery solution for this bike might be like.

Configuration is 10S, most current draw would be 5/8A with 25A burst.

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What is the C-rating on the Panasonic cells? The Samsung cells I've got there are 0.2C(typ)~2C(max) :?

There's some 3C 18650s starting to kick around now which would be pretty good for most legal ebike applications or there abouts. In bigger capacity packs (15-20ah) they'd be a pretty good solution for most mid spec road ebike requirements but I can't see them cutting it in Keplers build here he'll probably only be using a little ~5ah pack.
Lipo or GTFO

full-throttle said:

t3sla said:

I'm looking at what a viable Panasonic 18650 based battery solution for this bike might be like.

Configuration is 10S, most current draw would be 5/8A with 25A burst.

Click to expand...

What is the C-rating on the Panasonic cells? The Samsung cells I've got there are 0.2C(typ)~2C(max) :?

Click to expand...

3C constant 18650/18XX0 cells exist, the issues they aren't usually sold bare and have protected tabs (LVC/HVC) for higher powered flashlights/e-cigs.

For example you buy XYZ_Super_Dooper brand cell that is really a Sanyo/Samsung/Panasonic with a protected tab and a rewarp, the added size makes it a 18700.

If you look on the Panasonic website there is no spec sheet for the higher discharge cells, that is because they only OEM on sell to a third-party that have added protection circuitry.

The way around this is getting a carton of cells direct out the back of a factory.

I'd really like to see Kep use 18650 cells, as it will show just how great they are and fit along the lines of the high quality build.

It's like playing a game of MFK
M -18650
F - LiPo
K - SLA

For pre-built OEM packs I have seen 9Ah ~2Kg (over your ideal weight)
10S4P ~15A Cont / 18A 10Min / 35A few seconds Sec (not exactly your specs)
But this is off the shelf with mount and cable and well priced if you erm, get a sample


Maybe find an old busted one and re-use for your application

What would be the weight difference between a Hobbyking lipo and 18650 pack? Hobbyking pack would be 1.3kg. Not sure why hobby king lists 2 separate weights per pack.

Samsung ICR18650 are roughly 12% lighter and smaller vs zippy compact which are the smallest and lightest HK offer.
C-rate is the problem as there will be 10x more wasted in heat.

t3sla said:

It's like playing a game of MFK
M -18650
F - LiPo
K - SLA

Click to expand...

Makes perfect sense
/viewtopic.php?f=6&t=8482&p=354961#p354961
M - Jane
F - Kara
K -

One of the other main drivers of this project is to continue development of my friction drive design so I am finding this battery discussion very interesting. Although a super stealth bottom bracket config is one of my goals, using this bike a showcase setup for rear mount is also on the agenda.

The botton bracket setup is proving to be troublesome especially in conjunction with using a Schlumpf. Will need to see how this goes :?

UGH, BB! From memory you have to re-tap to use a Schlumpf

If you forgo the use of the standard BB ring mounted PAS sensor and magnet I have some clip on solutions typically used in road bikes.

Realistically you're going to have to deal with 26650 AKA the mistress, cylindrical LiFePo4 that puts out FTW.

http://www.batteryspace.com/26650serieslifepo4limnnicells.aspx

Yeah cylindrical A123s would be your best option for those sort of cells in small capacity. Pity the tool packs are still so expensive, they'd be a nice option for you kepler for friction drive sales. Just flog the units and tell them to go down to the hardware store and pick a suitable tool pack to power it.

hmmmm

A123 26650
12S2P, 4.6Ah, 1.4Kg, 140A Cont!

They pack guild for $0.3 a cell

http://www.ebay.com.au/itm/12-batte...ries&hash=item2c5dc3a166&_uhb=1#ht_3447wt_840

Same stuff used in 36V dewalt packs, no idea what the their BMS is rated for.
But you could use them as a turnkey solution, maybe glue them back to back, kinda like gun clips.
So that you flip it over when you are out of juice or make a parallel mould.
I can see the appeal of docking packs, especially with charging and dealing with customers

How cool would that be to just snap in a commercial tool pack into the top of the drive in the same way you snap it into your cordless drill. Might. Need to have a closer look doing something like that.

full-throttle said:

Samsung ICR18650 are roughly 12% lighter and smaller vs zippy compact which are the smallest and lightest HK offer.
C-rate is the problem as there will be 10x more wasted in heat.

Click to expand...

If you discharge a 30c lipo pack at 1c I'm willing to bet you will find a bit more than 5Ah from a 5Ah pack? I'm just guessing this is one of the reasons why a 15c 5Ah pack is lighter than a 40c 5ah pack. Or maybe it's just the weight of the larger wires/connectors.

It would be interesting to do a direct weight compare of 10s packs that give 5Ah at same C rate with all connectors etc.

just snap in a commercial tool pack

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I had this thought also. Have them arranged like spark plugs in a v8 or v12 engine

Do you think Makita or Ridged would sponsor a few builds if we had the tags showing. I could use a extra few packs