Practicality of a Electric MX bike?

[cheese]

So I've been thinking a bit lately, in the RC world, electric is taking over gas powered in the planes and cars. They seem to be using BLDC motors which are a brushless DC motor loosly bassed on a AC motor, Good things about them is that they are high tourqe and highly efficent. The huge advancments with lithium batteries too are making the possibliity of a electric bike possible too. I've been having a bit of a look on the net and it looks like you would be able to get a result similar to a 125 2 stroke bike adn last for about an hour.

Do you think that it would be somethign that would interest you guys?

[kro]

Mate, I can nearly last an hour, my bike has to go longer than that.

[davereid]

Actually, there is no such thing as a brushless DC motor. All "real" DC motors require a commutator and hence brushes. A brushless DC motor is actually an AC motor, with electronics converting the DC to AC. So, while you feed it 0 hz.. its actually an AC motor.

Efficiencies can be quite high, and as you have electronics controlling the rotating electric field you can get great control of RPM and torque.

But, its very hard for an electric motor to get the same type of energy density as liquid fuel motors. For example, the massive wind turbines in the Manawatu generate about 1.6 megawatt. Many superbikes produce almost 10% of that out of 1100 cc. So theres more horsepower in my garage than in one of those big electric machines.

And by comparison, 50 wind turbines produce about the same as 1 wartsila RTA96 diesel genset.

So... with current technology, liquid fuels are clear winners.

Cheers

Dave

[Ghost Lemur]

You can get an electric powered kids trials bikes. I'll see if I can find the link again.

As for the rest of us, naff that.

[Flight Engineer]

Even in RC although the battery technology has got good (thank goodness for cell phone development) it is still very expensive in relative terms to a ic motor when you consider initial purchase price, the life of the battery, possibility of damage in a crash. This is why currently the main popularity is in the smaller RC models, where cost effectiveness is greater. I'm no expert but I suspect getting cost effective batteries to produce the power required something the weight for a dirt bike is still a way off. But I also bet with the continuing pressure due noise and pollution in places like the US that we will get there at some point (maybe not pure electric but some other hybrid).

Dean

[Boosted]

Rather have the noise :)

[Ghost Lemur]

The company I was thinking of was OSET Bikes (http://www.osetbikes.com/index.html).

Would certainly consider getting them for the boys as their first motorcycles.

Personally give me the noise and smell of a dirty two stroke any day.

[GR81]

Rather have the noise :)
we noticed ;)

[xwhatsit]

I posted this a while ago: http://www.kiwibiker.co.nz/forums/showthread.php?p=784810#post784810

This guy seemed to have pretty good success, and decent range. However that bike is a bloody light thing; dont' know much about MX bikes, would assume they are pretty light too? Or do they need all super-reinforced frames or something, plus heavy-duty suspension?

Would be interested to see it done. The great thing about electric motors is that you have 100% torque, even from standstill. So that would be pretty good for MX bike, I'd imagine; plus, completely predictable power through the wheels (turn the throttle into like a volume knob; 0-100% of power, linearly).