My first e-bike project log named: "P.O.S."

[def215]

the title says it all. this is going to be my first e-bike build so im just going to use off the shelf parts so if i mess up something, its no biggie. also ill be using this as a commuter around the city and everything is a few miles away.
so here is what i have to work with:
razor scooter electronics from my last build that ive disassembled
and from that i have:
350 watt motor
speed controller-24 volts, 30amp max
a three speed hub-a shimano 333 hub
heres a pic of what i have so far.

that is my drivetrain. i want to use it as my intermediate shaft but i have ran across a thread in this section claiming that a member here would be using one of these hubs as a spindle drive so i might go with that. i find that to be very interesting because i always wanted a spindle drive bike, so i might be leaning toward that.
now all i need is a "victim" bike to put everything on it. im searching for a 16 or 20 inch bike so i can put all this electric stuff in it.
heres a rough mock up of what im thinking of how it can happen

hopefully you guys get an idea of everything and i can get it somewhat like that on a similar size frame.
what do you fellas from ES think of this. hopefully you guys will go easy on me since its my first e-bike build

 

[spinningmagnets]

I think this is a great project. I'm looking forward to the performance data. Don't feel bad about the motor being only 350W, the 3-speed trans (used as a jack-shaft) will be a big help, and the smaller motor should help you get very good range per battery size.

If you're open to suggestion, I wouldn't try a 16", I'd start with a 20" BMX-bike. You should be able to find one for $20 at a thrift store, or if you wait till the week after Christmas, you'll be able to find a dozen in the trash. Often when a kid gets a new bike, the old one gets tossed, or donated to a tax-deductable thrift store.

I've occasionally taken 2 free trash bikes and made one good one for a local kid, and once you start looking for them, you'll be suprised at how often you start to notice them. Also check the trash bin behind the local bike shop the day before trash pick-up.

 

[def215]

ill take your advice spinningmagnets on using a 20 inch bike. i wasnt sure which one i really wanted to build on but i was really leaning toward the 20 incher. anything bigger and i think it will be a little too cumbersome for me to handle, being a smaller guy of course. thats my cruiser bmx fitted with a 3-speed hub that i used for mock up. thats the basic idea of how i want everything to look. i dont want to victimize a perfectly good working machine...lol. i think ill check the thrift store, craigslist, and trashday like you mentioned, to see if i can find something suitable.

i was really reading up on this thread when i came across it while reading up on friction drive systems
http://endless-sphere.com/forums/viewtopic.php?f=28&t=6877&hilit=friction+drive+speed+hub
its on page 5 and 6 where im really looking into with the hub being the friction roller. i really like this idea but it seems as etard never finished his project. i might emulate this idea and see if it will work. maybe etard can chime in on my thread and give me some insight on his project.

 

[Zoot Katz]

the title says it all. this is going to be my first e-bike build . . . )

"First" is the operative word.
"Project" is a close second.
Have fun. Keep us posted.

 

[def215]

Keep us posted.

sure will.

so ive decided to go with the chain drive system with the 3-speed hub as my jackshaft. i wanted to get the highest ratio possible. i had a 15tooth primary on the motor to an 18 tooth on the hub. from the hub there was a 21 tooth and that will go out to a 52tooth on the wheel, which will be 20 inches. that gives me an overall ratio of 2.97:1, which is good for about 50 mph, which a 350 watt motor cant handle. i cant find anything that will really gear me down to where i want, so i resorted to making my own.i decided to make a 6 tooth. it will take me down to a 7.42:1 gear reduction, which i would need with a low wattage motor. also ill have 3 gears to play with.
(queing the photo montage)

how it looks before i started anything. in its idea stage.

the "diamond" in the rough

on the motor, ready to go.

i can see it coming together already.

 

[Miles]

Hi def,

I think the 6 tooth might be a step too far.... but as you've already made it, let's see what happens...

 

[liveforphysics]

Chordal motion may be +-20% of linear displacement.

But I admire anytime someone takes the challenge of making a part themselves. Good work!

 

[Miles]

Ref: http://chain-guide.com/basics/2-2-1-chordal-action.html

 

[liveforphysics]

Ref: http://chain-guide.com/basics/2-2-1-chordal-action.html

Ok ok, so 6t is more like 14% of linear displacement. I took a total blind guess at 20%, I think I did ok.

 

[Miles]

Yes.

 

[spinningmagnets]

Consider this as an option. It was an experiment for a cheap push-trailer using 20" wheels. The 47T chainring was from a trash-day bike, the disc was from a $2 skillet from the thrift store that had a thick flat bottom (but the non-stick surface was badly scratched), and the wheel was from a $10 thrift store BMX. I have found similar BMX's for free on trash-day, but I was in a hurry to take the pic.

The trailer frame was a hand-cart dolly (even after conversion to a trailer, it could still be used for moving boxes) that I got for $5 (again at the thrift store) but since it was heavy steel I sold the push-trailer cheap after I got the pics I wanted to show.

The 18T sprocket wasn't flat, it had a funnel-shaped curve near the center, so I had to cut a roughly 3" center hole for the disc to sit flat against the 18T. Once I drilled and bolted the disc down, I remounted the wheel and spun it so I could hold a felt maker still against the chainstays to make a perfectly concentric circle for the chainring holes.

If I recall correctly, TNC/Monster-Scooter make a 9T as their smallest drive-sprocket, and even then they're not for high-RPM. Aluminum is great for prototyping, and I respect you making your own sprocket. Once you are settled on the configuration of the drivetrain, you'll probably want a steel motor-sprocket for the small drive end, but aluminum is acceptable for large diameter sprockets/chainrings.

edit: I re-read your second post and you already adapted a 52T to the rear wheel! (Ron smacks his for head and says DOH!), so I can already guess you are considered a larger sprocket on the 3-speed jackshaft, and I'm guessing there were probably interference issues...

 

[torqueon]

I would use .25 pitch chain and sprockets from motor to jack shaft, this size looks weak but will handle alot more than one would think
The big avantage is lot of reduction in a small space. any good industerail warehouse wil have these.

 

[def215]

update:

thanks for all the great comments guys.

so ive decided to use my bmx as my platform to build my ebike on now and i also decided to ditch the 3-speed hub for now and save it for another project. this is what i hope it will turn out looking like:

a sketch up of what i would like my bike to look like when i am finished(drive system-wise)
so here is what i have so far:

i want it as stealth as possible so i am trying to hide everything in the frame. dont mind the zip tie holding the motor on. that will be replaced with another u-bolt or something similar.

didnt realize how tight everything was until i mounted everything up and snapped the pic.

it looks like a straight shot to the rear wheel. still need to mount the rear sprocket up. that will be on it soon. the speedometer will be relocated of course because the rear sprocket will definitely be in the way. i think ill keep the 6 tooth primary on it for now and see how i like it when its running, and as you stated spinningmagnets, its more of a prototype/testing thing when i made it. also i was just seeing how far i can go with my abilities too; i always enjoy a challenge like that...lol with the 6 tooth primary and the 52 tooth rear sprocket, this will give me an overall ratio of 8.66:1 and will max out at a good 20 mph, which is what i was aiming for.
more updates to come soon.

p.s.- the electric scooter thats in the background is running a homemade 6tooth aluminum sprocket and i so far holding up. but only time will tell if it will truly last...lol

 

[mwkeefer]

def,

You sure your not from South or West Philly? Nice work so far brother (diy drive sprockets with a drill press? - sweet!)... I mean it's ghettotabulous but shit, if it works... well, work it!

Were are going to have to get together... besides, I have spare parts = )_ (like crack to eBikers)!

I'll be in philly tommorow but only for a few moments, taking the folder to dad's for xmas dinner (he has no clue) so its a ride 2.5mi to amtrak paoli->30th then the R3 (I think) to swarthmore and 3.5mi ride from there... it's actually only 10mi of riding (round trip) so im only taking my emergency 145W charger along (I'll be there a while and my range in normal circumstances is 18-20mi).

It's too cold and there are too many idiots for me to just take the ride head on (sad since it's only 16.2 mi by shortest route and I could easily cover that one way and charge at destination) so I get to field the dozens of questions about the bike (which is fun I must admit) and I get to wow the kids by riding wheelies for a block or more without effort!

In either case, let me know if I can help out with the project!

-Mike

 

[def215]

thanks mike. yeah the drive sprocket was made using a cordless drill and files...lol. they dont work too bad considering that.

yeah. we should definitely meet up sometime mike. probably some time in the new year when i get back into the full swing of things after my second surgery and all. and besides, i want my bike together. i dont want to come to a shootout unarmed if you know what i mean...lol. i named my bike "Excep-TA" with all do respect poking fun at the mass transit system in philly(SEPTA). ill go out of my way to try to get places in any type of transportation, except SEPTA...lol(except the regional rails. im pretty sure they are very useful). taking mass transit in the city is always torture. it takes the same amount of time for me to get to school on a bike as it goes taking mass transit, which is ~30 minutes.

well enough of that. some more updates. so as i stated before i was gonna fit a 52 tooth chainring on the rear wheel but i still want my pedal function. i didnt have a hub that had the disc brake adapter, because if i IIRC, the 3-speed hub im using is from the 1980's. so my imagination got the best of me and i was in the eff'in zone. so after all said and done it came out looking like this:

now i have both drive sprockets for the pedals and motor.

chain is mounted and need to throw on a tensioner which will be soon.

i cant say its that stealth anymore. that 52tooth chainring is noticable to me from a mile away...lol

 

[mwkeefer]

Add a rear rack and pannier bags (for that size frame .. I'd look at Netbook bags, like little laptop bags and perfect for 20" panniers - it's what I hang on the folder, would hold alot of extra batteries too!) that will handle the sprocket issue...

For the chain and motor just fashion a simple splash guard from plastic (lexan, PVC, the stuff they use in bathrooms) and use wire ties to secure it within your chainstays... it will actually (I think) combined with a fender help to muffle chain noise in addition to hiding your drive system.. may even help aerodynamics a bit.

If you can't visualize what I mean... think about the plastic banner plate on a little kids 12 or 16" bike... you know the Thomas the train bikes and the plastic that covers the handlebars and is attached with wire ties... I can draw it up for ya if you want.

In philadelphia, the above would cover you well enough...

If you don't want panniers - go for at a minimum a rear rack with pannier hangers / supports and just make a plastic inside cover... even that wouldn't draw attention in philadelphia (*yet) as it would look like it was for water protection.

-Mike

 

[def215]

im not really feeling the pannier bags that much but i do like the idea of a rear rack.

so i think i am close to completion. just a few more odds and ends to tie up and itll be good to go. i dont really feel like typing so ill post pics and explain on the way.

there it goes in its current state. cant find room on its frame so ill opt to carry the batteries in the bag(SLA's are heavy as hell).

another pic of it

the battery/tool bag

my "dashboard" so to speak. my speedometer, brakes, throttle control and my ornament in the middle.

the rear wheel with the 52 tooth sprocket

i decided to gear it up some so im switching to a 8 tooth front to give me a 6.5:1 gear ratio if i can recall correctly

my homebrewed chain tension, well its more like a chain diverter so it doesnt hit the frame and fall off.

when i was testing to see if it worked, i noticed there is a lot of chain chatter. i guess it is the chain tensioner. but if i can get any input from other members on ES if they experience something similar with a similar setup like mines, please chime in.

 

[enoob]

not that i have any experience with that kind of setup but from experience with other chain driven machines id say try adding another chain wheel (or tensioner) as close as you can get to that small sprocket on the motor .

nice work by the way . ill be interested in seeing that unit move.

 

[def215]

Thanks enoob. Any help is better than no help...lol. I do still have a slight amount of slack in the chain so I think I'll try that. The "tensioner" on it right now really only keeps it on track and in line. There is one thing I kind of want to try that I saw on a bike forum that could possibly help my problem is a "ghost ring" but I'm not sure if something like that can handle speed. I'm just waiting for a fairly good weathered day so I can get some testing runs it and see how this whole rig performs...lol.

 

[def215]

so ive finally got around to getting a test run in for it to see what this thing can do and im pleased with what it has so far.
heres a vid of the test run i did.
[youtube]ST5XWbg0ux8[/youtube]
(vid is a little crappy because its from my cell phone, all i have at the moment)
it feels a bit sluggish but i guess its the wattage of the motor, which im thinking its a 250 watter now and not 350, 24 volts, and SLA's in cold weather.
it got a top speed of around 15-17 mph which felt pretty quick to me(ive never been on a bicycle moving that fast before). not sure if my bike computer was calibrated correctly but it seems consistent with the speed calculator that im using. so far im happy. im trying to push the limits of this thing during the initial testing period right now so i can work its bugs out so i can get it ready for the spring. did an awesome "burnout" on ice just to see it my drivetrain can take abuse, it was cool intil my batteries started giving in...lol

 

[crazy dreamer]

Hi Def,
your video aint working? i have been waiting for you to post your test run as i have a similar project on the go.
C.D

 

[def215]

very nice crazy dreamer.
i like it. it seems like you mounted your motor way more solidly than i did though. what are the specs on that thing because im pretty interested.

i just uploaded my vid on youtube and it told me it might take a while for the video to fully process. iyoure probably getting the same error message as im getting also. ill give it some time and ill check it again to see if it works. if not ill do another test run soon and upload that.

 

[crazy dreamer]

Hi Def,
the motor is a unite MY1016 250w with 11 tooth #25 pitch sprocket and 80 tooth minimoto sprocket on the rear free wheel. i estimate a top speed of around 18 mph on 24 volt sla's i am currently designing a suspended banana seat with a box underneath to house the batteries and controller.
C.D

 

[crazy dreamer]

i also picked one of these up out of the christmas trash!

should make a good project
C.D

 

[def215]

Hi Def,
the motor is a unite MY1016 250w with 11 tooth #25 pitch sprocket and 80 tooth minimoto sprocket on the rear free wheel. i estimate a top speed of around 18 mph on 24 volt sla's i am currently designing a suspended banana seat with a box underneath to house the batteries and controller.
C.D

i knew another build similar to mine would pop up sometime. with being on ES in the search function, i never came across something like this. im glad im not the only one with a setup like this...lol.

i think ive shouldve done what you did and used #25 chain and sprockets, but i opted for #40, so i cant gear it down as much as you have done, i have an 8 tooth motor sprocket and 52 tooth bicycle chainring on my rear wheel, which is close to your gear ratio you have. im also thinking my motor is a 250w like yours. theres not the oomph there that i was expecting.