Deacon's DIY Electric Bike Forum!

[rgvkid]

Hey Deac, so how is the new welder working out for you? Takes some practice but most of all make sure the surfeace is clean and if you grind off some of the mill scale you'll get a better contact. Don't worry about tumors, you can always clean them later. Better to have to much then too little.

[deacon]

I promised I would show the finished product so here is the bike that I built to help with my weight control. I have only ridden it up and down the driveway with no power so far but it does fine balance wise.

The motor is 350 watts... the drive is a coaster brake hub run by a bike chain to the motor. I have jbweld and sand on it. I had to weld the sprocket onto the motor but it seems to be okay. I did test it with some old batteries and it didn't fly apart.

The rack on the rear is for the batteries. The total additional weight will be about twenty pounds. Considering I weighed fifty pounds more when I started the bike riding, it is still light.

The batteries on the way are twelve amp hour. If I ran the bike wide open they would run 34 minutes. By being battery conscious and with the freewheel hub I should be able to stretch that some. I have no idea what the speed will be I'll have to come back and let you know.

I have a two speed switch on the handle bars. 12 volt on one leg 24 on the other and of course off. So I have pedal only, I have 12 volt helper 1/2 throttle and 24 volt helper full throttle.

Shoes is going to make a custom cover for the batteries. So there should be one more picture when it is all together.

[rgvkid]

Looks great Deac! How do you apply tension of the roller onto the tire? Looks like a good setup. I hope all works out smoothly.

[deacon]

Originally Posted by rgvkid

Looks great Deac! How do you apply tension of the roller onto the tire? Looks like a good setup. I hope all works out smoothly.

It has constant tension because the roller freewheels when the motor isnt turning. the motot assemble is on those hinges so I just tighten them down. and dont lift them

[Weedylot]

That should be darn well enough at 24 volts, I hope.
A nice minimalist application.

The bigger wheel in front is a nice hungry look!

[deacon]

Originally Posted by Weedylot

That should be darn well enough at 24 volts, I hope.
A nice minimalist application.

The bigger wheel in front is a nice hungry look!

The small back wheel, besides being easy to mount the bike, should make the balance batter with the battery pack over it. The whole bike should have the same approximate height. I hope that will keep the bike from being top heavy.

[sojudave]

Originally Posted by deacon

Yeah that where i got mine but the bore is wrong I am going to have to weld it to the sprocket on the motor. Since the 25 chain will work I'm going to try it as well. One of them if not both will work okay im sure.

Deacon, will this site help? I found it the other day and got excited that I could get the parts for a 600w proj for less than 400.00. Chinese scooter parts, wholesale scooter parts, ATV parts, dirt bike parts, 2 and 4-stroke engine parts, motorcycle parts,

[deacon]

I have their site already. I also have one from the guy on ebay who might be a little cheaper.

My welding on the sprocket proved to be below that necessary to hold up but...

I found out something to make the building of an ebike much easier. The scooter motor comes with a #25 sprocket. It seems as if you get a bit of #25 chain you can use it to hook it to the bike sprocket on the coaster hub as I have done. That way it is a simple bolt up proceedure, not requiring any welding at all.

Caution I have not tested this fully since it is too cold to ride but it works in the shop so I expect that it will work on the road course. However that remains to be seen. I had a spare motor with that sprocket so the change over wasn't too bad. I'll have to let you know how it works out.

the cost for the project should have been, if I had known about the sprocket...
one motor less than 30 bucks
one rear hub from a child's thrift store bike 8bucks for the bike.
one #25 chain probably 13 bucks
two white electrical extension cords about 3 bucks for both
two 12 amp hour batteries 60 bucks
I had the bike so I'm not counting it. it was already in that strange configuration so if you wanted that kind you would also need a second child's bike for the rear wheel and the crank set.

It comes in at roughly a hundred bucks more or less....

After I wrote this I realized I had to build the frame and buy the three way switch so probably $125 is closer to the cost of doing one plus the cost of the bike/

Also noteworthy is that this is intentionally a low performance build. It is to help me keep control of my weight and to keep the bike rehab benefits while making it possible for me to climb hills. If I lived at the beach a plain old bike would work as well.

[deacon]

I guess it's true you have to fail a few times before you can succeed. This one was a bummer. Oh it worked just as it was supposed to, but it just didn't have enough power to make a difference in the pedaling of the bike.

The same motor did when it was a direct drive. I guess the gearing cut the power to the wheel more than I thought.

I'm even doing more now. I attached the sprocket BG joe gave me to the front wheel. I am going to hook the electric motor over it and see what happens. I have the 11 tooth bike chain sprocket on the motor but I have no idea how it will work. But you guys will know when I do.

If this doesn't work I will be back to direct drive from the motor. See what that does.

[deacon]

I got the donated (thanks BGJoe) sprocket on and the motor setup for the bike sprocket. I even got them aligned. It took a while but they tested pretty darn good. I need a tensioner but that's it otherwise it works fine. I tested it on the driveway since without a tensioner I expect the chain to pop off any minute. It does pull me. I can't tell what if any speed it will do my driveway is too short. Of course it is going to rain any minute so I can't do any more tests today.


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