I want some advice on motorizing my bike.

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Discussion Overview

The discussion revolves around the concept of motorizing a bicycle, focusing on the required voltage for a DC motor, energy sources, and throttle synchronization. Participants explore various options for powering the motor, including battery types and alternative energy sources.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about the necessary voltage for a DC motor to turn the bicycle wheel and suggests electric power as a potential source.
  • Another participant proposes using four car batteries in series to achieve 48 volts, calculating the current needed for a 1 HP motor.
  • Concerns are raised about the weight of car batteries, with one participant suggesting that four batteries would be too heavy and asking for alternatives.
  • A participant shares a link to an electric bicycle motor kit available for purchase, indicating a potential solution for motorization.
  • Another suggestion is made to use two 24-volt batteries in series as a lighter alternative, although this would reduce the distance the bike could travel.
  • One participant argues that electric vehicles face challenges with power-to-weight ratios and suggests considering a gas motor instead.
  • A creative idea is proposed to use an AC generator powered by pedaling to charge a DC motor, with the possibility of incorporating a small battery for additional power.
  • A later reply expresses enthusiasm for the idea of converting mechanical energy to electrical energy and indicates plans to explore this further.

Areas of Agreement / Disagreement

Participants express differing views on the best energy source for motorizing the bike, with some favoring electric solutions and others suggesting gas motors. The discussion remains unresolved regarding the optimal approach and the feasibility of various options.

Contextual Notes

Participants mention limitations related to battery weight and power-to-weight ratios, indicating that these factors may influence the choice of energy source. The discussion also highlights the complexity of electric vehicle design.

Who May Find This Useful

Individuals interested in DIY projects for electric bicycles, those exploring alternative energy solutions for personal transportation, and enthusiasts looking for creative engineering ideas may find this discussion beneficial.

math_way
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Hi!

I thought of motorizing my 2 wheeler.
1) Now i want to know how much Voltage (DC motor) is required to turn my wheel.
2) The source of energy? (Maybe Electric). If electric, I know it will be difficult to use batteries to run the motor. Considering car batteries, they are just too heavy. Any suggestions?
3) Throttle. I need some help on that as well, as in synchornizing the wheel movement with the throttle.

Thank You.

Regards,
math_way
 
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I'm assuming you want to go more than 10 feet?

If so...4 car batteries hooked in series for 48 volts outta do the trick.

I'm guessing 1 HP outta do...that's about 746 watts for a 48 volt dc motor.

P=IV

746=I*48

Current will be 15.54...so figure 20 amps with magnetic field losses and so forth...#10 wires outta do the trick to the motor.

For throttle...use the same thing they use on the tyco trains...that little slide device that controls the speed of the train.

Have a nice day.
 
But each car battery weighs roughly 20 lbs... and 4 such batteries will weigh about 80 lbs. That's a little too much weight... any alternative?
 
I have been looking into this too and I found this on eBay for pretty cheap, I think , lol

It's a kit, they have others if you look

http://www.ebay.com/itm/48V1000W26-Front-Wheel-Electric-Bicycle-Motor-Kit-E-Bike-Cycling-Hub-Conversion-/390406828047?pt=LH_DefaultDomain_0&hash=item5ae60f700f
 
math_way said:
But each car battery weighs roughly 20 lbs... and 4 such batteries will weigh about 80 lbs. That's a little too much weight... any alternative?

Sure...two 24 volt batteries in series for 48 volts. Your motor scooter will now go half the distance as the 4 batteries.

Electric powered vehicles are difficult to make...and as you can see the power to weight ratio is not very good. There are some electric cars now...but they aren't exactly lighting the world on fire. Not yet anyway.

Try a gas motor. The power to weight ratio is amazing.
 
Last edited:
Here's possibly a better idea that would be more fun.

Power an DC motor with an AC generator into a full wave rectifier. The AC generator would be powered by your legs.

If you could get 1 HP out of your legs...this would translate into less than 1 HP to your motor due to heat and magnetic field losses...but still would be kinda nifty since you are just looking to play around.

Maybe you could add a small battery as well that could assist or get charged by your generator as well. Then figure out a way to charge your battery when you were going down hills and so forth...just like the hybrids.
 
psparky said:
Here's possibly a better idea that would be more fun.

Power an DC motor with an AC generator into a full wave rectifier. The AC generator would be powered by your legs.

If you could get 1 HP out of your legs...this would translate into less than 1 HP to your motor due to heat and magnetic field losses...but still would be kinda nifty since you are just looking to play around.

Maybe you could add a small battery as well that could assist or get charged by your generator as well. Then figure out a way to charge your battery when you were going down hills and so forth...just like the hybrids.

Nice Idea! I too thought of converting Mechanical Energy to Electrical Energy, therby powering my motor bike with the electrical energy. Sounds great! I'll see what I can do. And I'll update you on my progress. Thank You!
 

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