Well, I spent last weekend building the ultimate electric hybrid bicycle for Seattle riding. My first bike was more or less a prototype that taught me all I needed to know to put this one together.
Note how similar this bike looks to the $7,000 bike featured in a recent New York Times article. Similar design parameters usually lead to similar designs. That is why most airliners have two wings, engines mounted on pylons under those wings, and three tail feathers. However, this bike only cost $1,600 and I suspect it will outperform the expensive one in every way imaginable.
- I chose a full-suspension mountain bike frame because the roads and even the bike trails here are so bad. I wanted to isolate the batteries, controller and my butt from the shocks. I also jump off curbs a lot.
- I wired pairs of 36-volt Dewalt power tool batteries in series to get 72 volts and then wired each of these pairs in parallel. I can carry two, four, or six battery packs, depending on how long the trip will be.
- I replaced my 36-volt, ten-amp controller with a 72-volt, 35-amp version. It also has immediate start, which means the controller does not wait until the wheel is rolling before it puts power to the motor. This lets me get through intersections faster and safer (although I have to be careful or my front wheel lifts off the ground).
- I used a rear wheel motor because front wheels here tend to get bent by potholes and fixing one can be expensive if you have a motor mounted in it.
By doubling the voltage I gave this bike twice the power of my first one. That is a 100 percent increase in torque and speed. It is an incredible machine — efficient, fast, carbon neutral, and flexible.
I will post video of the bike in action when I get around to it.
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