Small Child's ebike build- what to use?

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I want to power a child's little 16" bmx. I guess like a 100 or 200 watt motor would work, maybe undervolted or undergeared to make it very slow. Like power wheels slow. I can pick up schwinn 250 motors for $20 locally. Or I could use an RC type motor I suppose. Bad idea? What do you ES guys think? Any advice or tips appreciated.
 
vanilla ice said:
I want to power a child's little 16" bmx. I guess like a 100 or 200 watt motor would work, maybe undervolted or undergeared to make it very slow. Like power wheels slow. I can pick up schwinn 250 motors for $20 locally. Or I could use an RC type motor I suppose. Bad idea? What do you ES guys think? Any advice or tips appreciated.

On a budget? A 4011 hub motor would have plenty of torque and plenty of non-speed. You can run them at 24 volts, that would be some cheap and small SLA 12 volt 7.5AH batteries (or less for less weight) I don't know how difficult it would be to get it into a wheel that size, but a front motor and batteries in the back would be a good balance with no fear of it ripping out the front fork with such low power. Heck I bet the thing could go 15 miles on a single charge. :D
 
Ypedal said:
wich ever system you decide on.. i'd suggest a remote-kill-switch , i've seen those on small ATV's, basically a cordless RF contactor switch to disable the power in the kid gets out of control..

Slow and safe if the name of the game here.. how old ?

Oh, excellent point! Maybe one of those fancy "seat" switches like they use on lawn tractors so the driver has to be sitting for it to work.
 
4 years old, yeah I was thinking dead man's switch and RF switch also. The schwinn 250 motor is non-geared and has #25 sprock. I think the stock chain is also that size. Maybe the speed will be ok at 12v?? I'm not sure if I want the pedals flailing around. I guess it wouldn't be so bad if the power is low enough. So the RC motors are too weak huh?
 
No hadn't looked at the pukka. Want something with pedals. There's not much space to work with at all on the little bike-

pTRU1-3387806reg.jpg


Looks like this one.
 
Don't take this wrong, but at that age I would let your kid peddle.

Mines 9 and borderline overweight, he needs all the exercise he can get.

I don't think a 4 yr old would be accompanying you on a long bike ride.

My kid at 9 doesn't treat his bike all that well, just drops it on its side and runs off. Left his previous bike out in the rain, etc.

If you go ahead, would watch the rear stay spacing for a hub motor, not sure that's it the same as the 135 mm adult bikes.
 
Yeah I don't think I will try this after all. I just wanted like a 100 watt low speed kind of deal so he doesn't tire out as fast. I was thinking of doing a chain drive 12v deal from a used 200 watt 24v escooter from the local classifieds or something. I see them for $20 to $40 all the time..

He's really good about taking care of his stuff, but that may change. Usually I ride along with my skate board or walk along. I can see all of this guy's ribs so he's really skinny. For right now all I worry about is him eating enough, not the exercise.
 
My daughter will, on occasion, take her 10 & 8 y/o girls along with the five year old boy on what I consider longer rides. As long as he is with everyone his energy level remains great but as soon as he is left with either of the girls the energy level is rapidly depleted as he finds other things that are more fun.

On a personal level I would put him on an electric bike right after I decided to shave with a chain saw. My wife has purchased electric vehicles for each grandchild when they were VERY young with this grandson as an exception. None of the children had the eye/hand coordination to safely operate the vehicles and these were "Barbie" jeeps and a "John Deere" thing with a trailer for one of the other grandsons. The girls were around five with the boy at four.

The primary result was the vehicles cluttered the garages of their parents. They required supervision at all times, something that was seldom available and the batteries would go dead from lack of charge. I do believe that given sufficient training they would have been able to use them but quite frankly even the kids became bored at three MPH.

Against my advice the oldest grandson was given an electric scooter, with a seat, at age six. This is a big boy, he looked eight or nine and had played soccer for two years. Within five minutes he had scrapped both knees, both elbows and dented the helmet. As expected he lost interest and I have no idea what happened to the scooter. He rides and enjoys his bike and I enjoy buying him the fancy new model every now and then as he shares growth spurts with weeds.

What all of these kids need is exercise and a regular bicycle provides that. The child has a feeling of accomplishment from learning to ride and gaining the stamina it takes to make distances. With the way the world is today it's not really possible to simply turn a child loose without supervision. To me it's amazing when I take the girls with me on a ride. They will ride five miles and beg for more.

But, this is for your child and all I have is an opinion and a little experience albeit with my grandkids rather than my own as all they had was regular bikes and back then it was safe to turn them loose in the neighborhood without fear of predators.

Good luck,
Mike
 
I agree with Deep -- I'm a teacher and work with kids everyday. I think it is a good learning curve just to deal with a regular pedal bike. I have students 4 - 13 and the older kids always ask about my ebike as I ride it to school. As much as I like kids to have cool experiences I still answer/lie to them that you need a drivers license to drive it. This ends all discussion about buying or building one. I do this because after much thought I conclude that a kid can get a road or mtn bike and have loads of adventures, excercise and lots to learn about him/herself, traffic and the like. On an ebike one accidental push on the throttle and you can be off the curb and into the road/traffic. I think it's an adult toy.

Al
 
A cop would have to be a real jerk to give you tick for a power-wheels-slow bike though. Thats the kind of speed I had in mind. As you say, those power wheels vehicles are very expensive, and IMO crap. I would never buy one but I wanted some thing powered for my boy to enjoy. I'll just hold off until he's ready for the real deal.
 
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