# Hybrid Bike with Generator & Treadmill Motor/Controller



## Ratso (Apr 1, 2017)

I want to do some experimenting with an electric bike/motorcycle but spent all of my project money during a recent hurricane, in part on a Honda 2200 generator. So I got an idea to possibly take a small motorcycle (or even a mini bike) with a busted engine and take the engine out and replace it with a mount for the generator and one for a treadmill motor (I have an old treadmill). I believe that the treadmill motor is a 130VDC motor and is already wired to a PWM controller. Maybe a mini-bike would be more doable to start with. I don't expect the motor to last forever or that I'm going to ride this thing to work but it would be fun to try out. Does this sound doable? Any recommendations? After I save up a bit more, I'd like to invest in some batteries and a hub motor.


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## MattsAwesomeStuff (Aug 10, 2017)

I've done it, on similar "spend zero dollars" budget.

It's doable.

The controller will not work. It will probably be a TRIAC-based AC chopper circuit. This type of circuit uses the 120 zero-crossings per second of a 60hz AC waveform coming out of a household socket to control the speed. 

Basically, every time the sine wave crosses zero, it shuts off power, then delays a certain amount of time before turning on again (the time delay is determined by the "throttle"). So for example, since that pulse will be reset no matter what after 1/120th of a second, if you delay half that time before turning on, it will be at half speed.

These transistors are super simple and super cheap and take advantage of that AC waveform. You'd need some other form of speed control.

I controlled mine with a super ghetto knife switch, and did speed control through the bike gears (ballpark) and slow start (to prevent chain snap) by just ganging up a bunch of scrap power resistors and toggling them into circuit for a few seconds (until they'd smoke) to give the chain a fighting chance.

I didn't ride it much, as I took it apart for final tuning, my family "helped" clean up and took all the custom-cut bolts and threw them into my misc unsorted bolt bin. I kinda gave up and only ever brought it out for demonstration ever again.

https://endless-sphere.com/forums/viewtopic.php?f=28&t=38022 <-- Build thread.

https://youtu.be/sc0HNuTwcBg

The generator... you probably won't have room for, but I'd make a cargo trailer for it. A "bob" style with a single wheel. Then you'll have infinite range.


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## brian_ (Feb 7, 2017)

Ratso said:


> I want to do some experimenting with an electric bike/motorcycle but spent all of my project money during a recent hurricane, in part on a Honda 2200 generator. So I got an idea to possibly take a small motorcycle (or even a mini bike) with a busted engine and take the engine out and replace it with a mount for the generator and one for a treadmill motor (I have an old treadmill). I believe that the treadmill motor is a 130VDC motor and is already wired to a PWM controller





MattsAwesomeStuff said:


> The controller will not work. It will probably be a TRIAC-based AC chopper circuit. This type of circuit uses the 120 zero-crossings per second of a 60hz AC waveform coming out of a household socket to control the speed.
> ...
> These transistors are super simple and super cheap and take advantage of that AC waveform. You'd need some other form of speed control.
> ...
> The generator... you probably won't have room for, but I'd make a cargo trailer for it.


Leaving out the generator is not an option when it's the only power source.

With only that generator and no battery, the only power source is the expected 120 V AC 60 Hz... so it would work. It would be inefficient and ineffective, but it would function just as it does in the treadmill.


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## MattsAwesomeStuff (Aug 10, 2017)

brian_ said:


> Leaving out the generator is not an option when it's the only power source.


...

Oh.

Hah.

Right.

No batteries.

Reading comprehension.



> With only that generator and no battery, the only power source is the expected 120 V AC 60 Hz... so it would work. It would be inefficient and ineffective, but it would function just as it does in the treadmill.


Presuming the genny can handle inductive loads.

The treadmill will be around 1500-1800 watts at max power. That'll be enough to travel 50-55 km/h (30-33 mph). If the genny can handle that, should be good to go.


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## Ratso (Apr 1, 2017)

Thanks for all the input! At first I was thinking of something with a hub motor connected to batteries (in the front hub) as well as an AC motor (maybe mid-mounted). The AC motor would run off of the generator and the generator would also charge (through DC outputs or through an AC connected charger when going slow or stopped) the batteries. The hub motor would be for acceleration (or possibly running out of gas) only while the AC motor would just run at cruising speed. I don't know the actual practicality of that though, for instance, speed control with an AC motor.

For my experiment, I may take a large mini-bike frame and extend it a bit to fit the generator. Since the motor will be considerably smaller and I could place it in a number of ways, I figure I can make it all fit.


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