help with electric bike driven through 3-speed gear hub?

[rudyauction509]

i've been looking at these:

http://www.monsterscooterparts.com/...ss-electric-motor-9-tooth-chain-sprocket.html

http://www.monsterscooterparts.com/...moto-9-tooth-8mm-05t-chain-sprocket-1018.html

I need a motor that can output to a bike sprocket for a possible near-future project involving an electric bike driven through a 3 speed internal gear hub. I can file down a 415 or 420 sprocket. But I need some advice on how to mount these motors in-frame, without welding or using anything other than hand tools and a drill, and any links to cheaper motors. I'm going to over volt them so I can't spend much on them. I also am very poor and this will be my first big project in almost a year. A 12-volt motor that's at least 200 watts would be perfect if anyone knows of one. It needs gear reduction because I am chaining it directly to the sprockets by the pedals (or directly to the 3 speed hub, which ever is easier). I will remove the pedals and make new foot rests - this is a no-human-power bike, to be built as cheaply as possible and then upgraded over the next year. The main issue here is mounting easily. Thanks in advanced.

 

[rudyauction509]

OK I was searching again for a cheaper motor and instead I found an easy mounting solution.
http://www.wikihow.com/Build-an-Inexpensive-Electric-Bicycle
I already have the batteries and controller in my collection of parts.

 

[16v4nrbrgr]

From my experience you're going to need about 600 watts before the thing will move under any sort of speed without burning out unassisted.

If you get one of the motors with brackets maybe you can clamp or bolt an angle iron mount to the bike. There are friction and mid-drive kits that work this way but they're not cheap when you add batteries.

In all honesty, I've spent a lot on my electric and a $200 2 stroke bicycle kit will outperform an electric you can put together for $1000.

If you want an inexpensive starter electric I suggest trying too find a Razor MX 500 with dead batts, and get new ones online cheap. Then you won't have to deal with mounting a motor, and can focus on making it faster. Overvolting works well to do this cheaply - up to a point, I've burnt two motors and two controllers overvolting at the grand total of over $300 of scrap haz mat.

The only reason that I have a need for an electric is to be able to ride without a motorcycle license and on offroad trails legally. If you don't have those requirements and money is tight, I would consider a gasoline engine because it will offer more bang for the buck. You'll really need to fabricate a lot of parts to save the maximum amount of money in either case.

 

[rudyauction509]

Ok I figured out my solution. I have 2 500-watt?? (guessing, got off craigslist) electric wheelchair motors, and a sprocket from an old motor kit that fits on them. I have been trying to burn these things out for 2-3 years now but they just keep going. 1 year in the rain and snow, underwater use, dragging me up a hill so steep that the light switch I was using caught on fire. I will use 1 at a time. The output speed is perfect to connect directly to a 3 speed hub for a top speed of about 15. I have half-finished the mount, though it takes 2 charges on my crappy drill to drill a single hole for the clamps or motor. I will post pics of what I have so far and the finished product, I plan to finish tomorrow, when I can buy a hole saw.

16v4nrbrgr, I'm doing this to see how much abuse it can take. My main electric is a craigslist razor e300 upgraded to a 400 watt motor overvolted to run at about 980 watts by my calculations. And it has a 20-mile range. (huge batteries) This thing is for the ORV park and the bike jumps across the street.

 

[rudyauction509]

Here's some pics, though the motor and mount are backwards. the motor faces up like in the pic but the mount goes on top, and on the other side of the bike frame. It's where it is to make drilling easier. The batteries will hang over the bike frame on aluminum shelves. I havn't started those yet, but they will be simple and shouldn't take long.

 

[paul]

looking forward to seeing the completed e-bike rudy. looking good so far

 

[rudyauction509]

Thanks. Just waiting on a friend to cut a hole for the sprocket in the plate. I hope to be able to test by the end of the day.

 

[KCvale]

I need a motor that can output to a bike sprocket for a possible near-future project involving an electric bike driven through a 3 speed internal gear hub.

It looks I am a little late to your topic since you bought a motor and making custom mounts and such but your initial goal was just to add an electric motor to your bike that would use the bikes gears correct?

Well, it don't get much easier or reliable than this.

You replace the bikes bottom bracket assembly with a 3-piece freewheel sealed bearing assembly with 2 sprockets.
Your pedals turn the back when you pedal, but when the motor takes over the dual front chains rings spin but the pedals don't.

~$90 to $120 depending on what your bike has already.

And a controller and motor that that just bolts to your bike.

I attached my controller to the battery I used but that is a special case, here are the exact parts.

Batteries of course are the single biggest cost, I am having a special 36V 1KW LI battery for a trike project with the same base being built now it is costing me $670 delivered but as far as the motor with controller and drive train go that is system you can install with with just a small crescent wrench though I certainly do not condone that but you did want it it 'easy' and for ~$400 without a battery ;-}

 

[rudyauction509]

I finished the battery shelves, they are 2 sheets of aluminum with a bolt to support the battery. The battery will be duct taped to the shelves with the bolt taking the vertical force until I can afford a decent bracket. They will hang over the frame by 2 long bolts, 1 of the bolts will go through the mounting plate to keep them from sliding. I will hopefully finish mounting everything in the next 2 hours.

 

[rudyauction509]

KCvale sorry I missed your post earlier that's a really nice setup! looks powerful. You say it's $400 without batteries? how many watts? that may be in my future, though the cost of this so far is scrap parts + $15 in nuts and bolts. Does it have gears? a big point I'm making with this is to be able to shift with electric power, but the free bike frame I got only works with a 3-speed hub.

 

[rudyauction509]

basically finished it. It's slow, but it would climb a wall. I'm going to change the chain setup tomorrow to work like a shift kit: motor sprocket to small or middle sprocket, large sprocket to wheel. I haven't hooked up the geared hub to a shifter, but it's a 2-speed, with neutral in the middle. It was in high (cable slack) on my test ride, top speed about 8 mph. I'm going for 14-20 high and 8-10 low.
I'm still amazed looking at KCvale's pics. That thing looks GREAT!

 

[paul]

when you get it all done and if you decide to paint it try some of the all in one paint they sell at home depot. has primer mixed in it and spray's on real nice. i did my battery's and the mounts i made with it and its great paint and holds well

 

[rudyauction509]

Added front brakes, changed gearing, added shifter today. Still haven't made a foot rest, other than a bar hanging from a piece of wire. I'm thinking a long threaded rod through the aluminum just in front of the crank sprockets. I also need a chain tensioner for the first chain, I'm going to use a derailleur sprocket bolted on the slack side with washers to adjust the chain's alignment. All for tomorrow. As of now, it runs about 8mph in low and 14mph in high and climbs all of the hills around my apartment easily. I plan to overvolt it to 36 volts when I get a better 3 speed hub.

One problem with it is something jumping, I think the first chain which is very loose right now, after I shift to high while moving fast. If I speed up the motor slowly and carefully until it engages, it works fine, and the hub handles all of the torque I can put on it without any signs of stress.

As for painting, I think that's a good idea, it would make it look a little better. I am all for all-in-one spray paints. Cheap, easy and usually decent quality. And covering scratches takes only seconds, which is very useful for someone who beats the cr@p out of his bikes, like me.

 

[KCvale]

basically finished it. It's slow, but it would climb a wall. I'm going to change the chain setup tomorrow to work like a shift kit: motor sprocket to small or middle sprocket, large sprocket to wheel.

Bummer you couldn't afford a freewheel bearing and cranks like this:
http://www.sickbikeparts.com/catalog/product_info.php?cPath=21&products_id=34

http://www.sickbikeparts.com/catalog/product_info.php?cPath=21&products_id=35

$41 + shipping. Just bolt on a couple of sprockets and you can not only pedal assist but just rest your feet on the pedals motionless when the motor works alone.

I haven't hooked up the geared hub to a shifter, but it's a 2-speed, with neutral in the middle. It was in high (cable slack) on my test ride, top speed about 8 mph. I'm going for 14-20 high and 8-10 low.

I could be wrong as I can't see the axle shifter part but the hub looks a standard Shimano Nexus 3-speed like I use on my gas shifters.
If that is the case there is NO neutral between gears, in fact I can't think of single internal shifter with a neutral.

Best guess is it is your handlebar shift lever. Either it moves to much or not enough, or you don't have the axle side shift mech on right. They are tricky little buggers, on a Nexus anyway, when in 2nd gear the white indicator through the window should be between the two yellow bars.

I'm still amazed looking at KCvale's pics. That thing looks GREAT!

Thanks, it was my second electric build and for me, this was the first.

Funny story about that customer build but that is not for your build topic unless you enjoy old female dwarf stories. You can't tell size by the pic but that is tiny kids bike she had and still needed to stand on tip toes to get on it ;-}

Anyway you had asked earlier if the Caddy was a shifter, indeed it is or what is the point right?

The Caddy came with a NuVinci 170S Continuously Variable Transmission. In short an internal shifting hub with a 1000 gears but in reality it works like a throttle to choose the gear ratio as there are no actual gears in it.

If you want to make your head hurt you can see how they work here.
http://www.fallbrooktech.com/nuvinci-technology

I must admit I like the NuVinci on an electric but anything gas a simple 3-speed gives you all the performance and you are not always having to be changing gears.

 

[rudyauction509]

Its a sturmey archer hub. I discovered neutral while spinning the wheel on a mount and manually pulling the shift lever. It has 2 step-up gears, one near direct drive and one about 2-1. Neither are direct drive, I looked closely and the wheel always went faster than the sprocket. It may have a middle gear, but I haven't been able to get it to work. Maybe it's broken? But for $8, it works fine. tomorrow I am going to dremel out a 16 tooth rear cassette sprocket to fit it to finalize my gearing, and Thursday hopefully go to 36 volts to increase speed and a 12-14 tooth sprocket to reduce torque on the hub. As of now, in low, it will wheelie from a stop, and in high goes just faster than my friend can run. The tire size is really weird, it's a Schwinn 24x1-3/8, a regular 24 inch tire won't fit, and a 26 inch is way to big. There was only one tire that fit out of the 200+ at the community bike shop. I'm thinking of putting the hub on a 26 inch rim for more tire options, the only problem is that the hub has less spoke holes. I haven't counted them, but it's obvious. I would have to just mix and match them to make it work. Also Thursday I am getting a rear rack so I may be able to re-do my ugly battery setup at the same time I add the third battery.

I actually had the SBP shift kit freewheel, but after I changed back because of chain problems caused by a weird bike frame, I lost most of the parts. It would be great for this bike except I would need a one way bearing on the motor output. Even moving the bike backwards requires me to lift the back wheel, because the motor is designed to stop dead when power is cut.

KCvale, how much do you charge to make something like this, and do you offer kits?

 

[KCvale]

Its a sturmey archer hub. I discovered neutral while spinning the wheel on a mount and manually pulling the shift lever. It has 2 step-up gears, one near direct drive and one about 2-1.

That is so odd. Every internal 3-speed shifter I have seen has 1st gear near 50% reduction, 2nd gear near 1:1, and 3rd 40-60% overdrive, thats what makes them so ideal for any motorized bike drive, it's all you need.

I actually had the SBP shift kit freewheel...
It would be great for this bike except I would need a one way bearing on the motor output.

Yep, the motors I have used came with motor freewheel already on it.

KCvale, how much do you charge to make something like this, and do you offer kits?

I built and shipped a 2-stroke shifter once, it was a nightmare and I won't do that again but an electric is another story so I may be willing to do that.

At the moment I am working on an electric adult shifting trike kit.
Actually the trike has been in operation for a couple of weeks with my crappy original battery but expect my custom designed battery pack to be on it's way this week. I'll see how well this custom battery works out and may come up with something for 2-wheelers.

Feel free to drop me an e-mail if you want to talk numbers for a build for you.

 

[rudyauction509]

I'm trying to figure out this hub. On the ones you work with, when you pull on the shift chain thing, do they shift up or down? I think mine was either modified or is just an odd model. The shifting seems backwards but I'm not sure; when I pull the chain, it shifts down into low.

 

[rudyauction509]

OK I messed around with it and did some research, the neutral is just a gap between middle and high gears. It's just really touchy to get into second gear. I have it working fine now.

 

[rudyauction509]

well, it's finished. I got all 3 gears working and setup the gearing. 12 in low, 18 in middle, 25 in high. I also overvolted to 36 volts. This thing beats my 49cc 2 stroke any day.

 

[KCvale]

the neutral is just a gap between middle and high gears.
. . .

well, it's finished. I got all 3 gears working and setup the gearing. 12 in low, 18 in middle, 25 in high. I also overvolted to 36 volts. This thing beats my 49cc 2 stroke any day.

I'm glad I could help with the shifter problem.

You might want to consider dropping the size of you rear wheel sprocket a tooth, more if it has more that 18 teeth now.
It's a $7 cheap easy performance improvement over maxing out at 25 with gears.