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Stone-age electric bicycles

On the weekend, an acquaintance showed me his battery-powered electric bicycle.

I was totally underwhelmed.

Given how cheap and easy it is to make such stuff these days, I had expected the electric bike would be light, efficient, ergonomic and fun to use.

This monstrosity was far from it.

I could not believe how heavy the motorized hub was, nor how primitive the power source was (a sealed lead-acid battery). Then there was the control system -- clearly designed and built by someone who didn't do a lot of electric bike-riding themselves.

So I decided to take a look around and see if this vehicle was typical of what's on offer out there.

The first place I looked was TradeMe of course.

Yep, it seems that the one I saw was pretty typical of the poor design and I was gobsmacked at the prices they demand for these things.

Take this one for example.

It appears to sport the same heavy, cast-metal hub that I encountered on the weekend -- although it does claim to have a lithium battery.

I rushed off to the Volto website to get some more info and found details of the Volto TDF03Z

Now it all looks very nice -- until you get to the weight figure: 28Kgs. That's a whopping 15-18Kgs more than your average bicycle.

Now batteries will account for some of that -- but I still can't get over the weight and bulk of that huge power-hub that all these things seem to use.

Why on earth don't they simply innovate a little?

Surely it would make more sense to set some electromagnets up on the frame, where the wheel rim passes close, and fit some powerful rare-earth magnets to the wheel rim. In effect, this would create a linear electric motor that was closed into a loop.

Benefits?

• Much lighter
• torque applied to the wheel rim, not hub
• better efficiencies
• simpler design/construction

So what have I missed? Why isn't anyone (that I've found) doing it this way?

Is the electric bike industry as lacking in inspiration and innovation as the wind-power industry perhaps?

Maybe these days it's all about being "seen to be green" rather than creating greener, more efficient solutions.

It's almost as if someone came up with this power-hub setup and then everyone else said "that looks near enough, let's just copy it".

This is also why we have wind and solar systems that rely on expensive inverters to turn their 48V of DC into 230V of AC when required -- instead of implementing the fault-tolerant, multiply redundant and highly scalable systems I've suggested previously in this column.

I know that at least a couple of Aardvark readers have built their own electric bikes and I'd love to hear from them. What were the things that drove your design? How is it going? What did it cost and if you did it again, how would you change things?

Are electric bikes even a viable option in NZ -- where so many cyclists seem to end up in hospital as a result of their interactions with cars and trucks?

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