Improvised e-bike?

Material:
A 500W / 127V drill, a 12V battery, a 12V / 127V inverter and a bell switch.

Motor:
It would be a drill 500W / 127V / 2800rpm
As 1rpm = 0.105 rad/s and W = Nm x rad/s:
500 = Nm x 2800x0.105, So I would have 1.7 Nm of torque.
By connecting a long shaft to the drill chuck and rolling it with rubber until it has a diameter equal to 1/10 of the diameter of the bike wheel, I would take to the bike wheel a torque of 17Nm and a rotation of 280rpm, axle in direct contact with the bike tire.
With this torque, I believe you can load 100kg on the bike and put it at a speed of 30km/h.

Batery:
It would be a 12V and 60Ah battery, which I believe would keep the 500W drill for over 1h.

Inverter:
As the drill works with 127V and the battery is 12V, I would have to use a 12V / 127V inverter that supports more than 500W.

Accelerator
As an accelerator, a bell switch could be used on the bike handlebar

Conclusion: I compared the cost of this with the cost of a 500W/12V motor for e-bikes and I noticed that the cost of this would be 4 times lower.

Where is the mistake in that?

That is 120Vac right?
Its a plug in corded drill using a 500W inverter

There are people on youtube who have done that. Pretty useless IMO, but if its really cheap or free then give it a go see what kind of speeds you achieve.

Maybe you can buy a cheap used motor and controller, then hunt down a battery.
Its wise to spend money upfront then try to cheap out on an ebike.
You wont be impressed with the drill motor setup, unless you are like 90lbs.

I'd recommend reading up some of the other friction drive threads for some details that might be important.

These are some of the threads (not everything listed is relevant; you'll have to decide which to look thru)
https://endless-sphere.com/forums/search.php?keywords=friction&terms=all&author=&sc=1&sf=titleonly&sr=topics&sk=t&sd=d&st=0&ch=300&t=0&submit=Search

Also note that drills may have bearings not intended for sideloading, so it might not work very well (for very long) unless you use pillow-bearings to support the roller ends.

ZealousidealSoup said:

Material:
A 500W / 127V drill, a 12V battery, a 12V / 127V inverter and a bell switch.

Motor:
It would be a drill 500W / 127V / 2800rpm
As 1rpm = 0.105 rad/s and W = Nm x rad/s:
500 = Nm x 2800x0.105, So I would have 1.7 Nm of torque.
By connecting a long shaft to the drill chuck and rolling it with rubber until it has a diameter equal to 1/10 of the diameter of the bike wheel, I would take to the bike wheel a torque of 17Nm and a rotation of 280rpm, axle in direct contact with the bike tire.
With this torque, I believe you can load 100kg on the bike and put it at a speed of 30km/h.

Batery:
It would be a 12V and 60Ah battery, which I believe would keep the 500W drill for over 1h.

Inverter:
As the drill works with 127V and the battery is 12V, I would have to use a 12V / 127V inverter that supports more than 500W.

Accelerator
As an accelerator, a bell switch could be used on the bike handlebar

Conclusion: I compared the cost of this with the cost of a 500W/12V motor for e-bikes and I noticed that the cost of this would be 4 times lower.

Where is the mistake in that?

Click to expand...

if you run the drill continuously with a load on it for long duration then it will probably overheat and may damage / burn up the drill motor.. try running your drill continuously for long duration off the bike first for testing..

I think your idea would work, just not for very long.

2 main problems:
First, A drill isn't rated for continuous duty. it can't run very long under load without overheating. it will work for a while, but you'll eventually fry the motor.
Second, the gears aren't built for that kind of continuous torque. it won't take long to wear them out.

If you have this stuff lying around unused, then go for it. could be fun. Don't expect it to last long, but it should be good for a trip around the block or two.

ZealousidealSoup said:

Conclusion: I compared the cost of this with the cost of a 500W/12V motor for e-bikes and I noticed that the cost of this would be 4 times lower.

Where is the mistake in that?

Click to expand...

It would be ten times less effective. :^)

OK, I'm just pulling numbers out of my butt. This is the internet after all.

But seriously, if you want an effective e-bike, get a simply hub wheel kit or find a cheap, non-working used e-bike for cheap and resurrect it. I saw one in a nearby town for $20 and was thinking of buying it just for the rack and fenders. The kit is a safer bet, but if money is dear and time is plenty ...

https://phoenix.craigslist.org/evl/bik/d/electric-bike/6505818998.html

One final note. For a real world practical e-bike you really should consider a lithium ion battery. That usually represents nearly half the cost of an e-bike that can travel useful distances. So that's a good place to focus on if trying to do things cheaply.

Post a pic or video if you get the drill thing working.