Nice idea, although LEDs have an extremely low power draw. Not sure if the gravity plus gearing would generate enough watts for the Pi.

USB is 5 volts at usually under 1 amp (.5 amps for USB 2 and .9 for USB 3). So I think that suggests about a 2.5-5 watt draw for USB, although I could be wrong -- long time since I took any EE classes. With very quick googling, I'm not getting a concrete number on the wattage of the (single?) LED in the Gravity Light, but one result suggested in the milliWatt range (60-80mW). Same post says that a cheap hand crank generates about 1 watt with vigorous cranking that will wear out your arm/hand quickly.

So, I'm thinking that 2.5-5 watts would require a much more heavy-duty and less portable gravity-fed system. Very much doable (bicycle pedaling can generate 50 watts fairly easily), but probably only with more bulk than what can power LED lighting.

have a dose of chill..with a side of philosophy:
http://videosift.com/video/will-cady-what-fills-the-gap-feat-alan-watts

here..have a dose of chill..with a side of philosophy:
http://videosift.com/video/will-cady-what-fills-the-gap-feat-alan-watts

here...have a dose of chill with a side of philosophy:
http://videosift.com/video/will-cady-what-fills-the-gap-feat-alan-watts

A generation or two ago I doubt that poor Guatemalans could get fat, regardless of culture, because they simply didn't have access to the surplus energy required. This surplus energy shows up in nitrate fertilizers used for agriculture, powered tools of all sorts, and manufactured goods, like used bicycles.

It comes, of course, from fossil fuels.

A bicycle may seem a simple and primitive device, but just try to build a bicycle chain in your home workshop and you will see that making safety bicycles is possible only in a modern industrial state. It's not surprising that the development of the safety bicycle only barely preceded that of the automobile and the airplane.

The bicimaquina raw material is discarded bicycles from richer people -- nothing wrong with that, it's good, frugal engineering. But it should be borne in mind when plotting the future that hardly used bicycles are not a renewable resource, and require energy and infrastructure to produce.

Bicycling does give one a good appreciation of the value of energy. For example, 125 Watts is a respectable output for a touring cyclist; keep that up for 8 solid hours, and you have one kilowatt-hour. One kW-hr is a day at hard labor. A typical household in the developed world uses the equivalent of the labor of three or four hard-laboring slaves every day.

Of course, those slaves aren't the most efficient. You'll notice that the machines shown all use a direct mechanical drive. They could generate electricity, but that would cost -- multiply a few 90% efficiencies together and pretty soon you're getting nothing done by leg power.

Bicycle drive does allow good power production from human beings, and multi-geared bicycles are adaptable to people of differing strength. Not as much fun as flipping a switch, but easier than turning a crank.

It's plain that cheap fossil fuels won't last forever, indeed they may not last for much longer, and probably will never be available to much of the world at the same level as we currently enjoy in the US or Australia. Will we find ourselves scouring garages and cellars for disused bicycles?

Ah, this young Jedi is so sure of his ideas. Like Alan Watts said, "When you receive the message hang up the phone." But, our young Jedi does not yet have the correct receiver. Have courage young padawan, the truth is out there, the force be with you.

Well, allow me to respectfully say that you (and he) are wrong.
Absolutely I would still save money without the grid. I already have paid to have a small battery bank in my system (>1KWH), so it wouldn't cost me much more to be completely grid free. As it is I barely send power to the grid, as I use most of my electricity as I produce it by doing housework during the daytime. (EDIT: If @Asmo did that, maybe just by using timers on large appliances to run them during the daytime, he would save a lot more, like up to 4.5 times as much as he saves today.) In the short run I would not save as much as I do currently, because I would need to buy more panels and a larger battery bank, and the batteries would need replacing sooner, but it would still be a huge savings in the end over buying grid power. The suggestion that it's not economically viable without the grid is simply wrong.
Once flywheels become popular, it will be far cheaper than it is today to store your own electricity, I'll probably get one to replace my batteries when they eventually die.
EDIT: A micro-hydro system could also store the power cleanly, but requires 2 large storage tanks, one raised as far as possible above the other, and a pump/turbine to move the water. For those with the space, that seems a good solution for power storage, and it's how some electric companies do it on a large scale already.

EDIT: I did the math, and to be completely grid free would cost me about $3000 more, and the upgrade would pay for itself in 2-3 years. Hmmm, now you've got me thinking.....Oh yeah, I forgot, my system can't run my large welder, the electric oven and stove together, or the hot tub directly, that's why I stuck with a grid tied system in the first place, I use too much electricity at once sometimes. Solar systems DO have some limitations, mine can only put out 6500 watts at once, max.

I'm surprised he didn't mention that Dr. James Watts is known for one of the more disastrous cases, that of Rosemary Kennedy who was left unable to walk or talk after suffering a lobotomy.

I use slightly less than that myself on average, but we have solar water heating (supplemented with gas), so that's a good savings (especially since it also heats the hot tub), and we replaced all our light bulbs with led bulbs when they became feasible last year. Now, we usually read between 400 and 1000 watts during the day (depending on how many lights I have on, and if the refrigerator is cycled on or not.) That's running a big screen TV, computer, and often ps4 almost all day, every day. We also have electric stove and oven...and I weld, adding somewhat to our total.

Yes, my battery bank is only useful for power outages. It's enough to keep the lights on and the fridge from thawing, but not much else. We get about 3-4 hours out of it if I don't notice the power went out, but can make it all night if we conserve. Our system is grid tied, and first powers the home, then tops off the batteries, then sells any excess to PG&E. To date, I've never drawn the batteries down to zero...but we do have a small generator to supplement it when the power's out for days. The average home would certainly need more, but a 10kwh battery should be plenty to make it through an average night without AC (we don't have AC here).

My current system could not produce that much, but close. I live in N California, one of the foggiest areas in the US. Because we have a renter, an electric hot tub, dishwasher, and electric washer and drier, we use slightly more than we generate at this point, but my system is upgradeable to 6500 watts of generation (I have less than 1/3 of that now) when panels get cheaper...and when I can find space for more.

My system is not flat to my roof, and I have 2 strings of 8 panels. With the solar water tubes, it takes up most of the south 1/2 of my roof (1200 sq ft home). I could maybe fit 4 more panels up there and still be able to walk around them to clean them, but any more and I'll need some mounting structure. I really want to add a small wind turbine to generate at night or when there's a storm...solar doesn't work in the dark.

In America, we still have some rebates for people adding solar to their homes, but they are drying up fast. 15-20 years ago, you could almost do it for free if you got every rebate available.

We used to have about 1-2 weeks of power outage where I live per year, and that was part of why we did they system. We hated having no power and losing food every year, and also hated paying the ever rising cost of electricity. Before adding our system, we had $4-500 a month electric bills, now we have <$100 in winter and sometimes a negative bill in summer...we pay our bill once a year now, lump sum at the end of 12 months.
On to your second post....
I often think...electric cars were popular and the norm in cities before Ford came along. It's still astonishing to me that it was basically dropped for a century as a technology (with minor exceptions). I'm glad someone had finally gone back to it and is trying to fix it's issues. If I could afford a Tesla, I would have one.

I also agree, people won't adopt the technology as long as they have to sacrifice lifestyle for it. I said the same thing, but I found that I don't change my lifestyle at all with my solar system, I just pay lower bills. I determined that buying a system would pay for itself in under 10 years, with the lifespan of a system being about 20 years, that's 10 years of free electricity! That all assumes electric rates didn't go up, and they certainly have gone up...but not for me. You just need to be sure you install enough panels to supply all your power, and you're there.

The battery thing is really mostly for non-grid tied systems, or emergencies. Most people don't use batteries at night, it's simpler and cheaper to just sell power to the grid during the day and buy it back at night if you can, using them as your battery. Perhaps this battery will change that, but with lead acid, it's hard to make them worth the cost.

Panels aren't that expensive, really. In many areas, with rebates, they can be near free. (some companies will even give them to you and split the power generated off your roof). It's a myth that solar is expensive...when compared to non-solar. Mine are paid for by bill savings already (8 years + in) so I'm saving money with them now, and my lifestyle has not suffered in the least. I have lights on if its dark, I watch TV all day, and use the computer all day, have tons of electric devices I use, and soon will power a pond, etc. I often think that my life is a much better example of how you can be 'green' without much change than Gore's. He really doesn't seem to walk the walk, but he can sure talk the talk.

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