Deacon's DIY Electric Bike Forum!

deacon · Feb 9, 2009

So now the friction drive bike is running. I have battery issues.

I bought a set of new batteries that I plan to use on the hub motor bike. I'm not sure how they attach to the hub. It they attach as a 24volt pack I will be able to just move them from one bike to the other. if they attach as two separate 12 volt batteries i will not. It's all in the connection.

I love trailers, even though I seldom use them. I have two 12inch scooter wheels that beg to be used. I am going to build a tiny trailer for the batteries. That one will be used on the friction drive bike at least.

I might be able to switch the trailer from bike to bike If the battery hookup will work. Then again I might not be able to. I will just have to wait and see. Either way I will have a battery trailer to at least carry batteries for the friction drive, which will kind of be cute lol.

It is my opinion that a custom bike should NOT strive to look like the Wallymart bike.

Egor · Feb 11, 2009

Deacon - The battery's should be separate, that way you can go without a controller. You will have to make a Series Parallel switch.You then start out on 12 then accelerate with 24. Keep us posted. Have fun, Dave

deacon · Feb 13, 2009

The battery cable to the controller had 24 bolts on it. The cable did the series connection making it 24 bolts into the controller.

I think that one of the scooters I cannibalized had them separated onto three pins. But t his hub had only two active pins the third was empty.

deacon · Feb 18, 2009

If you have ever tried to mount an electric friction motor to the front wheel of a bike you know a couple of things. First if you want to be able to pedal without the motor at times. then you need a hinge or similar device to give the motor the ability to put pressure on the wheel and to be raised completely. Then you need a spring to hold it down.

When the motor turns it creates torque so you have a twisting problem if you are using the single mounting point where the brake was originally. Now I have tried everything to prevent the twist. From drilling more holes to welding the motor frame. All had drawbacks of one kind or another.

finally I stumbled on the answer. bolt or weld your hinge to a flat bar of about 8 inches. center the drive wheel to the hole in the folk and bolt it on. Run a spring from the motor to the axle on the correct side. Now here is the simple but effective way to prevent twist.

Put a cable and turnbuckle on the opposite end of that 8" bar where it hangs over on the other side of the front wheel. Run your cable to the axle and just adjust the turnbuckle for tension.

The turnbuckle tension is on the mount not the motor, but the spring on the motor keeps the mount from twisting in the other direction. A simple answer to the torque movement problem on a front mount engine, that will not damage or mar the bike in anyway.

deacon · Feb 19, 2009

I wanted to post one more picture of this diy ebike. I rode it again today and since it stayed together except for a trailer bolt, I finished the battery holder and now I declare it mission accomplished. I hope I have better luck with that than George Bush did.

deacon · Feb 21, 2009

I think my next ebike will be chain driven. I have a hub motor working and a direct drive friction motor working so now I need a chain drive so I can fully evaluate them all. After my last chain drive failure I have given is some more thought.

My plan of attack is this....(it will change I am sure) To pick up a junker 26" mountain bike. Remove the derailuer and the chain guard. Take off the 26" rear wheel and cassette. Replace the rear wheel with a 24" with cassette that I have laying about.

Weld on a bracket so that I can lower the hand brake to fit. Use the previous brake bracket to attached a engine mount and a battery holder similar to those on my other bikes. See latest photos.

On this build I will probably use a controller so that I have a throttle for the emotor to try and match my pedaling ability. The pedals will move anytime the engine is on so I won't be able to ride it like a motorcycle or scooter. I need to exercise anyway and it should make for more range on the battery anyway.

Now one chain goes from the front chain ring to the smallest of the rear sprockets. And another chain from the emotor to the largest of the sprockets. I hope that and the throttle will take care of the gearing I should have.

The motor sprocket will be almost two inches and the rear sprockts is probably 6" or maybe a little more.

So any ideas toss them out I can use all the help I can get...

deacon · Feb 24, 2009

I rode the friction drive yesterday and the hub motor today and I have to tell you watt for watt the hub motor is more powerful by some. Is it 500 bucks more powerful, no. But since I have it, I would rather ride it. It is also more convenient since I don't to lift anything to ride it as a bike. It is also quieter.

But worth five hundred bucks no. fortunately my little one 250 watt only cost $275, without the batteries,still a good sized chunk more than a friction drive would cost to build.

deacon · Feb 24, 2009

I also began plans for the new chain drive electric today. I found out a few things interesting. First of all most scooter motors will come with a #25 sprocket. I had been trying to figure out a way to weld a bike size sprocket to those motors for some time. Now low and behold I found that it may not be necessary. I stress the May because I haven't tried it yet.

I salvaged a rear sprocket from a scooter that was given to me, but you can buy them I know. The hole in the center is pretty large. Large enough so that if you use your dremel and cut the teeth off the smallest sprocket on a mountain bike wheel, the scooter sprocket will fit down over it. With a little careful welding I might be able to attach it straight. The other four gears are available to rig a single speed chain up.

If so I can just stick some #25 chain over the scooter sprocket and ill be good to go. Just thought it might be of interest if anyone wants to build one. You could probably make it work better than me. If I can make this work on the test bike, I might just slide the hub motor on the front. If I pull with the front hub motor most of the time, the rear sprocket will freewheel. Then when I hit the bike killer hill I can just put in the chain drive motor.

Yeah it does sound good in theory.

deacon · Feb 27, 2009

There are two problems with ebikes for most people speed and range. Speed is not my problem I bought the smallest hub motor i could find to force me to pedal and get at least a little exercise.

Range now that is a kickbutt problem for sure. a set of 12 ah batteries is good for only about 4.5 miles. Not very much for sure.

I spend the morning redoing my bike luggage rack so that I could carry a second set. It was a miserable failure. The rack became too long so I went back to one set. I did set it so the battery packs are interchangeable easily. I can go from one pack to another on the luggage rack. I had already built a small trailer so I will just have to drag it along for the second battery pack, or maybe put both in it and use the luggage rack for groceries.

deacon · Mar 2, 2009

I broke down and refitted the black friction drive bike. With the weather being what it is I got bored. So I finished stripping out the scooter my grand daughter had. I took everything off it.

I used the wheels and tires for a trailer to carry my spare batteries. I pulled the controller and throttle so I decided what the heck, I would just put it on the bike, I am doing it only because I have two of them now so I might as well use this one. I have never found them very useful but I'll use it anyway.

I learned a thing or two about power management from the hub motor maybe I can make it work on the friction drive as well. I doubt it but I can try. the bike shop guy gave me a motor that appears to be larger than the one I was using before so I'll have to test it out.

deacon · Mar 6, 2009

I got the shock of my life today. I realized how stupid I really am. For a week I have been trying to figure out what was wrong with my old battery pack. I mean I built a new friction drive system and it ran like garbage. Today I tried it out and it still ran like garbage. I took it home and put my meter on the batteries and the read out good, well too good to be acting that way.

I discovered that the batteries weren't draining, the motor slowed down as it got hot. Then i remember that it was the motor given to me by the bike shop. They had removed it from a scooter because it lost power I expect. Geeze what an idiot I am. I was so narrowly focused on the used batteries that I overlooked the used motor. DUH...

The second shock came when I switched out the motor for one I know works and it ran like garbage as well. It has to be the battery pack after all. Oh well.

deacon · Mar 10, 2009

Im going to do what is kind of a double post but there is different information so I don't feel too bed.

This post is about the battery rack on the rear. It is made from steel corner post like are in a storage shelf set. The battery rack is separate from the holder that is permanently attached to the bike. The battery rack can be removed and swapped for a second one just like it.

So here is what was giving me fits for a while. I have been using the rear brake holder for the battery rack holder. That was the front secure point, then one drop rod on each side to the axle area.

So on this bike, since I have a front motor secured through the front brake hole, I wanted to keep the rear hand brake as well as the coaster brake. If I did that I was stumped as to what to use for the front secure point on the battery holder rack.

While messin' with the seat post I noticed the adjustment clamp. It had about a quarter inch of bolt showing between the ends. That was even after it was tight.

What I did was get an I bolt and thread the seat post clamp bolt through it. Then slip the threaded end through the battery rack holder and put a couple of nuts on it. Made an excellent security point and allowed me to keep the rear brake as well.

Just an idea you might be able to use.

deacon · Mar 11, 2009

I didn't get much of a chance to test the friction drive electric yesterday I was totally worn out after the build. Today early I added a little more tension and took off again on the mile course.

I judged it against my memory of the hub motor. The hub motor is probably similar to the chain drive motors.

The friction drive which is the easiest and cheapest of all to build seemed to be about 70% of the hub motor's efficiency. That was a 300watt friction drive vs a 250 hub motor.

It was also using a very efficient friction roller, one coated with sandpaper for maximum grip.

I have what I think is a more powerful motor. I am going to run it today with a less efficient roller. I'm not going to rate it until I put a sandpaper coat on the roller. It is ready to ride as soon as I get the batteries recharged to peak.

I wont have the sandpaper coat on till tomorrow so I have done about all I can do today. I am hoping my new batteries arrive so that I can mount them to the battery rack I made.

Egor · Mar 11, 2009

Deacon I am glad to see you are still having fun with bikes. I got a chance to ride an electric a few weeks ago, I liked it OK but one thing I did not like was how top heavy it was, I then understood why the battery packs are placed lower on the more popular models. I think the only way I would consider riding would be if I could have one with the lower center of gravity. Have fun, Dave

deacon · Mar 11, 2009

The bike I build has a three inch lower rear wheel. That puts the batteries on lower than the bike seat and about even with the front wheel. It is not so top heavy.

deacon · Mar 12, 2009

I took off on the more powerful friction drive today. for the first block it felt like it might be equal to the hub motor then disaster struck. The drive wheel began to wobble. I had ground too much of the weld off and it failed. The grinding was in an effort to get the drive balanced. It never happened. Oh well back to the drawing board.

DOC BOLM · Mar 12, 2009

We keep small 2000 watt generators on our trucks,they are around 3hp.Has anyone ever put a 110 volt motor on a bike and run it with the generator,HD

deacon · Mar 12, 2009

You know I just saw something about an electric bike pusher trailer. What you mention might be very possible if One went that way. The appeal to me is that it is all in one place. A completely self contained drive system. Just turn a couple of wing nuts and have a power bike. Take it off and ride the bike trails no power. Put it back on and ride home.

I am tired of my friction bike so I might just turn it into a friction drive push trailer test bike. Once I determine that it is feasible I can increase or modify the drive system.

I will have to lengthen the throttle wires but nothing else need be done. I have several trailer that will just need redesigning of the hitch. It will be a fun project. thanks for the push Doc.

deacon · Mar 12, 2009

I am going to experiment with friction drive on the trailer because I have that already set up, but I know I can buy a complete rear wheel assembly for a scooter and a motor and chain will make it run the trailer just fine. Should be a piece of cake once I get it all worked out.

Norman · Mar 12, 2009

Deacon your the wild man of electrics! I will have to start experimenting with them some time.
Norman

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