Commuter E-Bike Optimization

[the e wind]

Welcome to my first new thread.

I'm coming at all of you in my last year as an undergrad student of Appropriate Technology (http://sustec.appstate.edu/) over in Boone, NC, a very hilly area prime for E-Bike use. One of the things we do in the AT department is put ourselves as researchers into other peoples shoes and attempt to solve a technological problem in a sustainable manner on a small scale. In that vein, I've been conducting E-Bike research for about a year with funding largely provided by our Office of Student Research (a few hundred dollars per semester). That's all well and good, but in the spring semester I will be spending the majority of my credit hours (a.k.a. my weekdays) trying to answer 1 fundamental question:

What constitutes the optimal setup for the average Joe who wants a lightweight, lower powered (sub 746w) E-Bike mostly for commuting? I know there's a lot of hot rodders here, but my intent is to focus on the needs of the commuter/recreation population, a.k.a. people who are not going to try to triple their max amperage. I'm talking about an E-Bike light enough to pedal, carry up the stairs, an E-Bike that any "cyclist" can readily adopt as their own.

I'll be spending January-May building my best rendition of what an E-Bike can look like for that type of person, and I highly value any input from all you folks at EF. I have been lurking a while now and feel this this the most useful place I could be documenting my work. My current line of thinking for the design is: a lightweight R.C. mid-drive with 2 stage belt reduction designed to fit into the middle triangle of most bikes (excluding full suspension). I will be building it on a 2005 Cannondale F5 frame, as well as experimenting with solar range-extending options.

-My first burning question is if anyone has any experience with scorpion motors, specifically their: http://www.scorpionsystem.com/catalog/multicopter/motor_5/mii-40/MII_4010_360/

low kV, high power output, low voltage, whats the catch??

With a motor like that I will also need to work out a 2-stage reduction. I'm thinking a Gates belt drive, and I'm planning on using a little grant funding to pay for someone to help me with the intricacies of machining such a part. I am a beginner on the lathe. I will upload some design drawings later. The pedal chain will go up, similar to a Hanebrink, to 2 exposed cogs. One will catch the pedalling via freewheel and one will feed the combined drive out to the rear wheel.

Goal: Top speed of 28mph and average power rating of around 350w. It doesn't have to be as fast as it should be refined.

Thank you all. I will update this thread regularly as the design and build progresses.

 

[amberwolf]

What constitutes the optimal setup for the average Joe who wants a lightweight, lower powered (sub 746w) E-Bike mostly for commuting?

There isn't one.

"Optimal" depends on each individual's commute, terrain, weather, winds, bike style, riding style, required range, speeds, etc.


There's no "average" whole bike that fits "optimally"; one bike might "work" for a lot of people, but it won't be "optimal" for hardly any of them.


Not even counting the motor/electric situation, just the bike itself would be different for different people, because each bike has to fit the individual to be comfortable for them to ride. There is no one-size-fits-all pedal bike, so there can't be an ebike like that either.

Even disregarding fit, bikes can be very different for different commute (and other) needs, just because of terrain and weather.

Here in Phoenix, for instance, it's mostly flat. So a singlespeed bike might even be practical for a fair number of commuters that don't need to stop and start a lot. But for a longer distance commute with lots of stops and starts, and some of the few hills around here, they'd probably be better off with a multispeed bike.

Then there's road conditions--much of the roads here are in poor or bad shape, and an unsuspended pedal bike can be quite a rough ride on them--a heavier ebike can be even worse. Minimal suspension helps, but it makes the bike heavier...so depending on the commute it might actuallly be better to not have suspension, just so that it's light enough to put onto the on-bus and on-train bike racks for really long commutes that couldn't be done in a reasonable time even on an ebike.

Then there's speeds...a commute might be in a situation where it can only be done at a low speed, say 10MPH or less. Another might have to be at teh max allowed speed (in AZ--other places can be different) of 20MPH, either for time's sake or other reasons. An ebike that's optimized for one speed either won't be able to do the other, or will not be as efficient (maybe not nearly so) at the other speed.

Even a change in jobs that makes a different commute for the same person may require a different bike (pedal or ebike) to do it, dependign on how drastic the difference is and what factors change.


That's just a few of the possible things that can be very different for different people, and there is no real "average" bike that can truly be "optimal" for all those different things.


Note that I'm writing this as a commuter on pedal bikes long before I had to start motorizing mine, so this is all from experience.





EDIT: Also, as a commuter, it needs to be totally reliable and just work everytime. For many, that probably means a hubmotor, partly so that if nothing else the entire regular pedal drivetrain is totally separate from the motor system so that if either fails, the other is still available. This is one of several reasons I wound up changing from middrive to hub on my own commuters.

It doesn't mean a middrive can't work, or can't be reliable, but there's a lot that has to be done to make a middrive sealed up and whatnot for weather/etc., as well as bulletproofing the drivetrain, when a hubmotor may well already be all set to go for the same conditions.

Alternatively, another commuter may not be able to use a hubmotor for some reason--let's say they need quickrelease wheels that are very light, so they can take them off to stick the bike into some tiny space for some part of the commute, or for storage at the destination or whatever. Could be other reasons...in that case, a middrive or even a friction drive might make a lot of sense.


Basically, I just want to point out that there's so many possibilities that you can't really make a single optimal bike for an average person, simply because there isn't exactly an average that would fit it.

 

[dogman dan]

EF is the website, endless-fussing.

Well, IMO, you just blew out the average joe part of the equation when you chose a complicated RC motor mid drive.

And, it's debatable whether light weight to carry up stairs is needed by the average joe. The average college student for sure, but the "typical" purchaser of an ebike in the USA is actually in his 50's, or older. That's a fact. He tends to be out of apartment living. But another market segment with some size is the DUI guy, who can be any age. He could be in apartments, or homeless.

Anyway, for the average joe. http://www.pedegoelectricbikes.com/ They didn't get to where that company is, by selling a product tailored for an Endless Sphere wacko/hot rodder. They sell tons of these bikes to the average joe.

For the guy living in the 3rd floor of Joes Apartment, here's a very nice take on the lightweight commuter. http://www.maxwellmotorbikes.com/

Lastly, you need to look at what the major bike companies will be showing in the bike shops in 2016. Tons of relatively light e bikes splashing this spring. All with mid drives by bosch or shimano. The majors have bet millions(billions?) on it. It's already taken off with a bullet in Amsterdam, and it's spreading through Europe like a wild fire.

Sorry man, but the giga companies did the research you are working on, and bet the farm on mid drives integrated into the bottom bracket.

 

[the e wind]

Thanks for all the thoughtful responses.

To clarify a few things: It seems I need to specialize my performance expectations. By average joe, I think I mean myself. Speed and power expectations: would like to be able to clip along the flats at ~28, mean hills at at least 10-12, and have enough beef to go down mountains as fast as any other vehicle on the road. I got a Cannondale F5, front sus. frame for 5 bucks that I would like to use, but everything else is still being ironed out. I will have around 5 months for the actual build, which means I want to plan on building it in around half that time to account for delays (and to write a couple papers on the topic). I will be directly fulfilling 6 credit hours on the project, so a generous portion of my weekdays will be available, as well as a full wood shop and basic machining processes (mill, lathe, cutting, etc). I am almost positive I would like to see it come together as a mid drive. I feel like a hub motor mounted in the bottom part of the triangle, with batteries taking up the rest of the frame is the best option for weight distribution and gearing. That led me along to the idea of using an R/C drive. I do not need more than 746 watts continuous, and am planning a volume-style pot. knob that dictates 0-746 watts (continuous) of assistance. The bike will need to be able to handle the mountain bike park as well as the pedestrian friendly greenways at appropriate speeds, with enough oomph for street riding at 20-25.

Here it is:

Hub motor mid-drive vs. R/C mid drive?

Picture that both systems would function at 0-746 watts, depending on conditions and setting. I am well aware that the R/C drive will take considerably longer to design and build, but if I wanted to lay down and mess with any ordinary E-Bike I would just order a hill-topper kit from clean republic (not dissing, that is an excellent option for someone else).

I am attempting to build a mid drive that avoids the BB based on my experience with sucky freewheeling cranks. There will be no fw crank in this design. That is the point. To build a mid drive which totally bypasses the need to mess with your BB. Also, no hub motor because I want gears. You would want gears up here too.

Thanks

 

[the e wind]

Update: having written out the idea to you all, I feel as though my mid-hub motor plan (akin to many I've seen on here like this dude https://endless-sphere.com/forums/viewtopic.php?p=290115#p290115) sounds alot less difficult. Besides the fact that I've studied this drive more and have more developed mounting plans, It would afford me more time to spend on the pedelec settings and solar experimentation (the latter is technically the focus of the grant). My single biggest challenge is the mounting of the "pedal in" chain and the "drive out" chain on the hub motor itself.

I will be combing through other forum topics on this part, but to my knowledge everyone who has built a mid drive in this manner has had to machine that part. Correct me if I'm wrong, but that part is for sale nowhere.

 

[dogman dan]

Ahhh, clearly a Joe from Lake Woebegone, where all the Joes are "above average"

FWIW, a stock commercial 500w geared rear hubmotor with 48v battery and 20-25 amps controller (1000w) will meet your specifications to the letter.

Mac 10 T hubmotor for example, or similar design 10t geared motor.

But,,,,, no fun there, an hour or so to bolt it on and off riding. That would be more fun, riding right away, for the average Joe. But above average Joe needs to CREATE!

Have fun!!!

 

[Voltron]

Off topic...But nice campus at ASU. Did some high school science camps there, and then hang gliding later on... beautiful area. You better focus on small wheel climbing power if you're going up Grandfather Mtn. :wink:

 

[amberwolf]

Update: having written out the idea to you all, I feel as though my mid-hub motor plan (akin to many I've seen on here like this dude https://endless-sphere.com/forums/viewtopic.php?p=290115#p290115) sounds alot less difficult.

If you mean this one:

then that doesn't sound like the way you were wanting to do it--that pcture shows a pretty "standard" way of doing it, running chain from motor to cranks, then chain from cranks to rear wheel like normal.

My single biggest challenge is the mounting of the "pedal in" chain and the "drive out" chain on the hub motor itself.

It's easy to find cranks/chainrings with freewheels so they're not driven by the motor while it's driving the chain, but can still drive the chain themselves (they would also drive the motor, unless there is also a freewheel at the motor). Look around the forum for BBS or GNG type drives and they basically do this; their parts would probably work for you.

You might be able to adapt those parts to work on the motor instead of the cranks, so the cranks drive thru the motor (like Rassy's 9C-driven tadpole trike).

I will be combing through other forum topics on this part, but to my knowledge everyone who has built a mid drive in this manner has had to machine that part. Correct me if I'm wrong, but that part is for sale nowhere.

Since it depends on which hubmotor you're going to use, and which bike you're going to put it on, then it'd be hard to design a cheap reliable universal mount, so it's unlikely to find any production ones for sale unless they are for a specific motor and frame.

The only production ones I know of are for the StokeMonkey and the similar City-something (sorry can't remember) drive, which are meant for longer cargo bikes (or bikes using the Xtracycle setup), which have an almost empty rear triangle to put it in.

 

[dogman dan]

Best way to eliminate the low quality freewheeling crank, is to do it stokemonkey style, and have the motor turn the pedals when you run it. When off, you will be pushing through the cogging of the motor though.

Or, get really old school, and drive the rear wheel from the right hand side. Uhhh, like go buy a cheap currie kit from superkids. It doesn't get much cheaper than those brushed motors they use. And they are torque monsters!d

But again, more fun to build your own whatever. motor on top of a rear rack, driving a gear bolted to the disc mount of the rear wheel is one traditional way. I see bikes like that driven by a weed whacker motor all the time. Or mount motor in the triangle, if you have the room.

I don't mean to quash your inventiveness, but somebody has done it all already, likely Amberwolf has. Franken bikes are fun! My own style is more like standard off the shelf drive stuff, and have my fun with the bike frame itself. I just can't out do those Chinese engineers. And it's the frame designs that really make a bike a good commuter, or bad.

Sneak peek of my latest frankenbike. It's built more for grocery getting than commute, but for many, carrying a load of groceries on the way home is a vital part of a bike commute.

 

[TroySmith80]

I haven't read the whole thread, but in response to the original post:

28mph is too fast. I think 20 is plenty.

Geared hub motor is the way to go IMHO. Simple, Clean, Simple, Clean plus they're simple and clean! When i say clean, i mean in appearance and perception. You're talking about most people, average commuters, not hot rodders, enthusiasts or special users. The regular folk want a bike that looks like a bike. They don't need to go super fast, and they don't need tons of torque. They just want a bike that doesn't make them sweat. 750 or even 500 watts would be plenty of power. The less power there is, the less sophisticated the control can be while still not making a difficult experience for unskilled riders.

If you're talking the mass manufacturing route, the new mid-drive packages like bosch and shimano may work well. I still think hub drives are probably better as long as you don't have a 250w power limit.

I think a really sensitive and well-programmed torque sensing pedal assist might work wonderfully, but i've never ridden one i liked. That said, i haven't ridden many. Mostly i've ridden bikes with throttle controls.

 

[Voltron]

Hey Dogman... I really like where you're going with the whole big front wheel, small back wheel, long straight run of the tubing from head tube to rear axle look... but I could be biased

 

[dogman dan]

You know your bike, and John in CR's, along with the edgrunner, ODK, etc were the inspiration.

The only thing I'm doing really different with this frame is the mixte style top tube, which will create a nice battery tray. Open top box, so it's effectively able to carry any size 18650 pack, up to about 12" long. Smaller battery tray behind the seat. It will easily carry 2000wh when done, without a complicated or funny shaped permanent battery box.

Build thread coming soon. Should be test riding it by the end of the weekend.

DEFINITELY, will build one for big fat mag scooter wheel someday. For now, not so trusting of my welding for anything over 30-35 mph.

 

[Voltron]

hey, thx! This one did turn out pretty special on the way it rides, and already had a rack welded in for a battery when I got it ( and the second rack is the body off a kids Razor type scooter, thats just sitting on the top tube with the seatpost holding it upright..you can just lift it off for single battery sprint mode! ). I'm rolling with a little more than 2100 watt hours (72v with 2 15ah paralleled up) when its in distance mode. And the big fat scooter motor is great... no spokes to break, oversize axle, the small diameter gets up up speed quickly, the casting def adds a heat sink effect, and it has enough grunt to take me and my girlfriend up to the top of our local mountains at 25 to 35 the whole way when I put the passenger seat on. It made it REALLY worth buying the broken down Extreme 600B shitty scooter it came off of...and running it with a generic $60 ebay controller. You can get all the benefits of the scooter motor without HAVING to go 40... but its pretty hard not to!


In heavy mode during a 40 miler trip...


Edit... sorry about the thread hijack OP... lol

 

[the e wind]

Heres a quik update:

The Clinton Global Initiative E-Bike Feasibility study is in full swing. I have placed orders for the two bikes that will comprise the study. I will start a new thread to detail the Feasibility Study, it is a plan to capture carbon emissions offset data from participants in an E-Bike loan program. Test subjects are given a GPS-equipped bike for 1 month; whilst they ride we will be capturing data about the quantity and quality of their commutes. It will then be overlaid with reported data about their previous commutes carbon footprint. From that we should have nice pretty numbers detailing EXACTLY how many ounces of petroleum you will have saved, or diverted from use. One bike will be a 350w bafang mid-drive equipped Motobecane Fantom 29er hardtail from bikes direct with a 36v 10ah water bottle mount battery. The other bike will be a Gravity Brutus 1 speed fatbike with a 750w rear bafang hub and 36v 10ah water bottle battery. I thought to build one bike on each end of the (mtb) spectrum. The first one is for the few who can appreciate the technical superiority of a mid drive, the second one is for the "Average Joe" that several E.F. members dutifully pointed out. Build first for reliability, I then funked up the "Average Joe" idea by giving it 1hp and the trendiest frame style on planet earth atm. They will be fitted with overkill (see below) safety lights and a rear rack for goodies. I am planning on using the spybike gps platform for data collection, mostly because they are reliable and that it seems to be the stealthiest.

In the meantime, before the new shiny gets here, we are rebuilding our old bike. Mostly sourced from the used camping gear store, it will temporarily return to the back burner when the CGI bikes arrive. So heres a run down of the "optimization" that is being done with bike numero uno.

This is the first bike:

- GNG 36v 350w motor kit parts moved from a janky Jamis to a 2005 cannondale F5 frame w/avid disc brakes, a.k.a. much mo betta
- beat up front shock replaced by better 100mm sus. fork
-frame paint removed with a coarse drill brush, cleaned & pained with prime, black then clear (the whole bike will be blacked out, save for blue pedals and hbar grips)
-single speed w/tensioner on the rear, 36/48/48 on the front. Crank made from sick bike parts' heavy duty freewheel components. Outside 48 is driven by the motor, while the middle 48 and the 36 serve as the bike's two speeds. I didn't choose these gears but they are about what we were looking for. We got a good deal on a lot of these parts from friends in the area. BTW everyone, ReGear used camping store in Boone, NC is the sheeeeiiiiit. Check it out adventurers! Good deals and great peeps.
-Vistop ridiculous lazer beam USB tailight. $15 and can't be beat. I'm not allowed to use the flash setting on night bikes because my buddies can't see anything in the dark except for me! But trust me, don't get it in blue. The cops don't seem to understand it and may think you are one of them... for me neither option is favorable.
-20w overkill led headlight. Cause too much is better than not enough
- Battery: in addition to the odd shaped lithium brick we acquired last year, a friend in the department has loaned me a fancy AllCell 37v 11.6ah pack that perfectly fits into this , a really F*ing small bag for that many watts! I believe he paid over $400 for the pack.

-The bike was primarily designed to go up hills especially well, and the jacked-up front tire due to bigger fork and front-facing battery will add to this ability. I have found bikes with more forward leanability and upright geometries tend to do better on off-road mtb trails and other types of steep inclines.
-In the future we have the ability to change the controller and unleash the beast, or a full HP(750w+) from the current 350w setup.

I will be starting a new thread soon that details more about the Clinton Global Initiative's E-Bike User Study. Thank you for all of your continued interest and support!