Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

The World's Lightest Electric Vehicle

kickstarter.com

Post reply on HN
Print view View original

161–170 of 174 posts

Re: The World's Lightest Electric Vehicle

#161

Post by khafra »

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…

> There's no equivalent to this behavior in any other vehicle.

http://www.youtube.com/watch?v=puLeE7sESeI

Re: The World's Lightest Electric Vehicle

#162

Post by muraiki »

wwweston wrote: post #106
muraiki wrote: post #51

Earlier quoted context omitted.

Where I live, there are many urban areas but also many hills / roads with long inclines. Longboarding isn't that popular here because: 1) You can't longboard up a hill, or even much of an incline. 2) More importantly, when you go _down_ a hill, it's pretty difficult to stop quickly (this is why I personally stopped longboarding) This device would help with both problems!

> More importantly, when you go _down_ a hill, it's pretty difficult to stop quickly (this is why I personally stopped longboarding) This might help you stop the longboard quickly, but will it help you stop quickly (but not too quickly)?

Good point! The stop will never be instant... and you'd better have good grip on your shoes, too.

While I think this product will be pretty neat, I can't see it revolutionizing transportation simply because longboarding requires a good amount of mental energy in comparison to a scooter or bike. But I have to admit, it is seriously fun, and the sensation of gliding is awesome.

Re: The World's Lightest Electric Vehicle

#163

Post by khafra »

thomas-st wrote: post #8

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

Well, shoot. Looks illegal in Florida too, from a combination of http://www.flhsmv.gov/fhp/misc/News/ScooterRel.htm and http://www.leg.state.fl.us/statutes/index.cfm?App_mode=Displ... (definition #27).

http://www.leg.state.fl.us/statutes/index.cfm?App_mode=Displ... section (83) seems to have been added specifically to make Segways legal, so perhaps someone with the resources for lobbying and/or a court battle could make these boards legal.

Re: The World's Lightest Electric Vehicle

#164

Post by tjoff »

avree wrote: post #14
typicalrunt wrote: post #3

Great idea. I'm surprised nobody has done this before (but they probably have, I'm no longer a skateboarder). But I'm wondering about the prices. $10 stickers and $40 t-shirts are still advertising, so people are paying to advertise for your company? That doesn't seem right. In reality, they are really trying to push people to spend $1200 for a board. Even the $1099 pledge is a complete rip-off since you spend $100 l…

The pricing seems like a complete rip-off, to be honest. $10 for a sticker? $40 for a t-shirt? $1000 for a skateboard? For comparison, you can buy a top-of-the-line longboard for $200, full kit. An essentially equivalent product [1] is selling for $500 a pop, half the price. That's more in line with what I'd pay for a luxury product like this. Also, I'm not sure how comfortable this would actually be to carry around.…

You are not buying a sticker. You are interested in a product and decide to help them out. In return, as a token of gratitude for your help, you get a sticker. If the sticker would cost as much as the pledge it would be completely pointless.

Re: The World's Lightest Electric Vehicle

#165

Post by exDM69 »

eurleif wrote: post #102
andrewjshults wrote: post #101

Earlier quoted context omitted.

Sudden deceleration (or acceleration) is probably the last thing you want if the remote disconnects. I'd guess some audible alarm letting you know the remote is no longer functioning + disconnecting the drive system (motors and brakes) so it functions as a regular skateboard would be the safest way to handle that issue.

That might be less than ideal if you were going downhill. Or if you had accelerated to maximum speed, were heading toward an intersection, and planned to hit the brakes before you got there.

I speak from (literally) painful experience. You do not want to have a board decelerating under you, especially when going down hill. If you do not have a decent foot braking technique, you should not ride longboards downhill. Foot braking is (IMO) the most difficult part of longboarding and very easy to screw up, sometimes it's better to try to stay on the board than even attempt braking.

A very slow brake application might be fine, but there has to be an alarm to the rider before that.

Longboards are very dangerous. Usually it's fear and inadequate kicking technique that keeps you from going too fast. I hope that people riding these boards will learn breaking do not rely solely on the engines.

Re: The World's Lightest Electric Vehicle

#166

Post by ChuckMcM »

sbierwagen wrote: post #135
indiecore wrote: post #121

Earlier quoted context omitted.

I'd assume that you'd have a rad over the bottom of the board and the motor housing that uses the air going by as it moves to dump the heat. At least that's my first idea, since I'm not a skateboard engineer it's probably not even close.

They'll just be air-cooled: 2KW motors in a skateboard are going spend very little of their time running at max load. I of course have no idea what the average load is, but a reasonable wild ass guess is ~100W.

My experience with DC motors was that they got hottest when starting and stopping, that was the result of a high current demand for torque and relatively low operating speed with meant minimal airflow. If you're going up a hill you're easily burning 1 - 1.5 HP or a .75 - 1kW of power. They look very cool, can't wait to see one 'in the flesh' as it were.

Re: The World's Lightest Electric Vehicle

#167

Post by JoeAltmaier »

pg wrote: post #41

This is one of those things that's like Google in the sense that it seems to be just an improvement on existing technology, but in fact is enough of an improvement that it's qualitatively different. In all the startups we've funded I don't think I've seen one whose product was so enthusiastically embraced by YC partners. Three bought one of these boards. One says it "changed his life."

I can see its a life-changer. Among the skateboarding crowd. I just think its a smaller demographic than they'd hoped.

Re: The World's Lightest Electric Vehicle

#168

Post by test450 »

pg wrote: post #66
FrojoS wrote: post #63

Earlier quoted context omitted.

I remember you wrote in an essay, that the Segway 'failed' because it makes people look lazy, like a 'smug', when they ride it and that changing the position to skateboard style might be the only change required. [1] Well, its not a Segway yet, but seem like we're getting there. But maybe this is the optimum already. edit: found it [1] http://www.paulgraham.com/segway.html

Curiously enough there was another startup this batch that did the converse: used Segway-like balancing technology in what will probably turn out to be a better way: http://doublerobotics.com

That still looks lame. OTOH, recently saw this segway tech in downtown Chicago and dude looked like he was from the future. http://solowheel.com/

Re: The World's Lightest Electric Vehicle

#170

Post by dredmorbius »

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…

I've had the somewhat peculiar experience of braking on a bike when the handlebars weren't completely attached to the frame.

Being able to apply a stopping force without simultaneously being able to fully brace your upper body against a solidly connected part of the bike was a very different, and to my mind, rather unsafe, condition.

I'd think liability issues would pretty grossly limit the merchantability of the powered skateboard. Electric scooters offer the benefit of a handlebar as well.

Post reply on HN