Where's my hoverboard

4795303 Back to the Future Part II lied to me! It lied to all of us!

-Kirb.

Uhhh... we have hoverboards now... they just aren't at the same level as the ones in the movie... for the moment...

YAKS SMASH!

That was... something.

WHERE ARE THE INVENTORS!? WHY AREN'T THEY DOING SOMETHING?!

You may be disappointed. I am relieved we do not live in a grimdark future where all games use Kinect except for baby toys.

We kinda have hoverboards and flying cars... But not close to how they were portrayed. Hoverboards only work on specific platforms, and flying cars are more like planes that can be driven like a car.

We're close. But we got wide flat-screen TVs, somewhat automated diners, I-phones, and such.

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Except for G4, the future kinda stinks. Excuse while I go sit sadly in a corner and wish it was the 80's again.

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The 80s ended before my mom even met my dad

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No, we really don’t. The so‐called hoverboards that Hendo make are less than worthless — even as a starting point for research. They bring literally nothing new to the table and would require quantum leaps in battery technology and/or electric motors to get any real run time. They still wouldn’t be in any way practical (can only run on conductive non‐ferromagnetic surfaces) or cost effective (an assload of quad ’copters would let you fly for a fraction of the cost of copper‐ or aluminium‐plating every surface you wish to hover over).

[T]hey just aren't at the same level as the ones in the movie... for the moment...

For the moment? That implies we can get there. Remember when I said it would require quantum leaps? That wasn’t hyperbole. Just to levitate at incredibly short distances for supremely limited amounts of time requires copious amounts of power. Being able to get “air time” would require lightening the board by an order of magnitude… which, considering the bulk of the weight is in the batteries, is only possible if we can either increase batteries’ energy density by a touch more than an order of magnitude or design an electric motor with an equivalent increase in energy efficiency. That would leave us with a board light enough to get “air time” comparable to a skateboarder with lead boots and still have supremely limited running time. Increasing batteries’ energy density by two or three orders of magnitude (or electric motors’ energy efficiency by the same, or splitting the difference) is the bare minimum to even approach a hoverboard of practical weight with a running time longer than a sad joke.
There are even more problems than just that, but those are the ones that are likely insurmountable.

Sorry guys, we had to go back and remove flying cars from the timeline. They were cool, and the countryside looks prettier without roads, but they were frankly far too dangerous. Ever seen a car crash? Imagine the same thing five hundred feet in the air at 300mph. We couldn't let just anyone play around with those things.

On the bright side, this timeline gets GPS satellites, Wi-Fi, and Youtube. Self-driving cars should be coming soon, too.

4795303 In testing. Commercial Mass produced hover boards should be available by this time next year.

4795628 There have already been some pretty nice advances in 'battery' technology that should be coming into the market at some point (using ridiculously high-energy-density capacitors based on nanomaterials since it's the surface area of a capacitor that determines the charge it can hold).

Huh. Actually, looking up 'supercapacitors', they're available now.

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Costs $3000, buddy.

4795821 At least it's not $9,999,999.

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While they’re fine for certain applications lithium–ion batteries actually have greater energy density, which is what is actually the limiting factor on run time. (10–25× the energy density, depending on manufacturer.)

The Hendo hoverboard weighs ~90 kilogrammes. When I said orders of magnitude that wasn’t hyperbole.

4803838 The article said they'd make laptops run 10 times longer. I doubt that was by making them 250 times heavier. Maybe those ones aren't on the market then.

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Waiting to be bought

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Are you talking about the hybrids discussed in this article? If so, pay attention to the comments section:

In other words, what they really made was a typical hybrid supercapacitor which falls somewhere on the scale between supercaps and lithium–ion. This is very far from combining the advantages of batteries and supercapacitors; rather, they made a supercapacitor which has a higher energy density than high‐end supercapacitors (42 Wh/l vs. 7) but can’t handle nearly as many charge/discharge cycles (10,000 in the new design vs. typically 100,000–1,000,000 for most modern supercaps).
― Joel Detrow

Or were you talking about just the general state of the art, as discussed in this National Geographic article? If so, do note that it’s actually talking about the exact same advance, interviewing the exact same person, only this article is from August 2013 whereas the Gizmag article I linked previously is from April 2015.