If it defies the laws of physics then it isn’t too difficult to assume it is a hoax. Remember Kickstarter isn’t about investment. It’s about giving a gift of money to someone who pitches an idea or product. My biggest concern about crowdfunding is the lack of rules that govern it.

3,000mph isn’t an important measurement. The question is not of speed, but of KE. Something weighing more than a bullet but traveling slower will cause as much or more damage–think of a 300kg wrecking ball smashing into a house at 40mph, versus an 80g 9mm round at 580mph.

We use flywheels for continuous backup power storage in high-power operations such as keeping up data centers or 500kW television broadcast equipment. I’ve had my cubicle 8 feet from a window looking out into a picnic area, with a block wall separating me from the high-energy flywheel 4 feet away. That flywheel would turn that wall to fine asbestos dust if it went AWOL.

mv^2/2 = E
v^2= 2E/m

v2 = 15 * 3.6 million / 750
= 108 million. /750
= .144 million.
v = 144 m/sec

Now that’s the average speed, given the pics, the rim speed will be somewhat higher. Call it 200 m/sec or about 2/3 the speed of sound.

Well, as best I can discover, a 750-pound flywheel that stores 15 kWh will likely spin at about 30,000 RPM. My 5,000 mph rim speed was perhaps somewhat of an exaggeration. More likely the rim speed would be closer to 3,000 mph, but still, the authorities will never license a 3,000 mph flywheel for above ground residential use. A good treatment of the basic physics of actual flywheels is given at: http://rpm2.8k.com/basics.htm
There is just no way to rediscover the flywheel. Batteries will beat it out in the market place. By the way, it makes sense to suppose Panasonic has heard of flywheels.
Theoretical longevity of flywheels just isn’t much of a bonus. The flywheel economics suffer from the same economic problem that permanent stainless steel residential roofs, siding, and plumbing do. No one wants to buy a permanent building to use for a temporary lifespan. In the US the average residence changes hands about ever seven years.

The argument for cost using Velkess over a battery storage solution is described in terms of savings over the lifetime of the product’s operational use. So one can argue that a battery has a finite existence of a few years before needing replacement whereas a flywheel if properly maintained can last “x” number of years spreading the costs. Without a price tag there is no way to know if the claim will prove true. And without an operational flywheel working “x” number of years there is no way to validate the savings that will be derived. In the meantime Panasonic is selling a home solar and battery storage system in the Asian and European markets. See http://www.21stcentech.com/energy-update-home-energy-storage-technology-commercial/.

And therein lies the major fly in the flywheel ointment. The real breakthrough technology for flywheels is not how to balance them, suspend them, and make low cost low friction bearings, but rather extremely strong materials that can constantly and reliably resist the huge centrifugal forces. They can’t spin the 25-pound flywheel any faster without centrifugal forces explosively disassembling the wheel. That might be a moderate problem for a 25-pound wheel, but imagine the explosive disassembly of a 750-pound wheel. Think in terms of a suitcase nuke detonating in the basement. I just don’t see commercial viability.

Apparently Li-ion batteries could and should sell for about $1,000 kW. Catastrophic failures of 15 kWh banks of Li-ion batteries are nothing like suitcase nukes. I just don’t see how the 750-pound flywheel system sells for less than $15,000. So the batteries seem lighter, more compact, and safer. Unless Velkess has made some breakthrough in super strong materials, it doesn’t look like a good investment.