(Warning: Following comment irrelevant to OP's subject.) Wow, that's amazing! There're so many interesting mechanical (and electro-mechanical) innovations on your Technology page. My appreciation for Hacker News just went up several notches since it's attracting folks like you. Are you funded? I hope so.
Who else is building such stuff that isn't just computer science/engineering?
We're of course intending to raise funds. At this stage we're writing the business plan, putting together the engineering drawings, doing simulations, and sourcing components for the first prototype build. We'll be moving into fundraising mode soon.
That is both interesting and awesome. I just looked at your website. Good luck, and I hope you'll keep us all informed about your progress. (I'd buy one!)
Energy density Energy density
by mass (MJ/kg) by volume (MJ/L)
Gasoline 46.9 34.6
Lithium ion battery 0.72 1.9
Lead acid battery 0.11 0.17
Compressed air in fiber-wound
bottle at 200 bar (at 24°C) 0.1 0.1
compressed air in steel bottle
at 200 bar (at 24°C) 0.04 0.1
Yes, we have. We're not intending to use 200 bar air, and we have to aim at a substantially more efficient vehicle, and even then we need a much larger tank than normal.
But compared to batteries they're very, very cheap. We think we can hit the range required, and that's what really matters.
We'd scale from 300 to 700 bar as the market allows. In the Asian market, for example, range and bulk is less of an issue than cost.
We're actually aiming at creating a scooter first, and other vehicles later.
The hydrogen tanks are much more sophisticated than we need. In particular they require a plastic liner (because hydrogen is so damned small). We just need carbon fiber wound tanks. These are manufactured to a higher precision but are not fundamentally different from 300 bar tanks which are fairly cheap (ie: you can buy single quantities of 9 L tanks for $500 - $600).
It's only a guess, but we think we can keep the tank price for a scooter below $1000, and for a car, below $3000. This is dependent on carbon fiber prices, and how efficient we can make the engine and drivetrain.
The important thing is that we can expect prices to improve handsomely while t goes to infinity, whereas batteries have had a lot of the manufacturing improvements that they're going to get.
Modern cars are quite complicated devices, even if the median vehicle contains no technical innovation at all. This is one reason we're doing a scooter first.
Empirically, when you improve the weight of a car by a factor of 10% it improves the fuel usage by a factor of nearly 8%. Ballast is an expensive way to get stability.
