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The World's Lightest Electric Vehicle

kickstarter.com

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Re: The World's Lightest Electric Vehicle

#81

Post by jonnycowboy »

skdoo wrote: post #49
thomas-st wrote: post #8

Seems like it's illegal to use in California: http://www.dmv.ca.gov/pubs/vctop/d11/vc21968.htm

We're still researching all the legal issues that vary from state to state. So far, we've never heard of a ticket being issued, and all the cops who have seen it think it's a fantastic idea. I think the biggest factor will be how responsible our new users are.

You might have luck in voluntarily limiting the power output to 1,000W and trying to follow the California guidelines for electric bicycles. Then gradually petition the government to delete the current motorized skateboard law.

http://en.wikipedia.org/wiki/Electric_bicycle_laws#Californi...

Re: The World's Lightest Electric Vehicle

#82

Post by skdoo »

jonnycowboy wrote: post #76
jonmrodriguez wrote: post #72

Earlier quoted context omitted.

As far as the profit margin, one barrier to just building this yourself is the NRE for a suitable brushless motor controller that does speed control, handles unknown and varying load torque, and does motor braking. Or do you know of an existing alternative controller?

They are using off-the-shelf brushless motor controllers (from what I can gather) and off-the-shelf brushless motors. There are many makers of ESCs with your requirements including from the now-ubiquitous HobbyKing, both sensored and sensorless (for RC car applications) including this one: http://www.hobbyking.com/hobbyking/store/__17234__Hobby_King... which will do variable engine braking as well.

Our motor control ESCs, remote control electronics, battery management systems, and software are entirely custom. Off-the-shelf RC parts aren't smooth, reliable, safe, or quiet enough.

Re: The World's Lightest Electric Vehicle

#83

Post by hrktb »

ajross wrote: post #53
IanDrake wrote: post #34

Earlier quoted context omitted.

Maybe I'm thinking about it wrong. Slowing down vs. braking, I mean. If I'm going 20mph, "braking" to me means coming to a stop in an equivalent distance as a car or bike going the same speed. Are the brakes that you've used stable at that rate of deceleration?

It's not so much the brakes being stable, it's the operator's body with its c.g. 1m above the board. A maximum deceleration for tires on a good road is generally 0.6-0.8G. So in order to avoid being (literally) thrown off the board the rider needs to be leaning backwards by 30-40 degrees before applying the brakes. There's no equivalent to this behavior in any other vehicle. In a car you just hit the pedal, on a bike…

In a bike just sqeueezing the handle will also throw you away, especially when downhill. It takes practice as well to be able to move your gravity center backward in emergency brakings.

Re: The World's Lightest Electric Vehicle

#84

Post by jonnycowboy »

skdoo wrote: post #82
jonnycowboy wrote: post #76

Earlier quoted context omitted.

They are using off-the-shelf brushless motor controllers (from what I can gather) and off-the-shelf brushless motors. There are many makers of ESCs with your requirements including from the now-ubiquitous HobbyKing, both sensored and sensorless (for RC car applications) including this one: http://www.hobbyking.com/hobbyking/store/__17234__Hobby_King... which will do variable engine braking as well.

Our motor control ESCs, remote control electronics, battery management systems, and software are entirely custom. Off-the-shelf RC parts aren't smooth, reliable, safe, or quiet enough.

My bad, I misunderstood your comment that you were using "(relatively) cheap brushless motor controllers".

Re: The World's Lightest Electric Vehicle

#87

Post by skdoo »

polshaw wrote: post #75
skdoo wrote: post #44

Co-founder here. Feel free to ask questions!

2KW sounds a hell of a lot, when a 250W motor on a bike can get up to 20mph? Do you actually use the full 2KW of power? it seems like it would throw the rider to me. I'm willing to bet from ebike knowledge that the regenerative braking is more of a marketing feature, and may not even break even with the added weight. Have you done tests on this? Others have touched upon price so i'll ask if you had any concerns about…

The key is to have enough power for hills, but make it controlled enough that you don't throw the rider. From the rider's perspective, the board has so much power it's like the hill isn't even there, but it's still gentle on acceleration and braking.

Regen braking doesn't add any weight for us.

Liability is an issue for sure, and we're handling it just like any other vehicle or consumer product.

Re: The World's Lightest Electric Vehicle

#88

Post by skdoo »

NickM wrote: post #80
skdoo wrote: post #44

Co-founder here. Feel free to ask questions!

Are the boards waterproof? I would love to have one but I live in an area that gets a lot of rain, and I'd be terrified of getting caught in a storm and ruining my $1200 board. On the flip side, if it does handle water okay, then I imagine boarding in the rain could be a lot of fun :)

Water resistant, but I wouldn't advise using them in a downpour. The biggest concern is a lack of traction with slick longboard wheels more than damage to the electronics.
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