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Discussion Starter #1
Dunno if the Gravity Light has been discussed here before but I just happened to see this youtube vid, a bag of rocks is hooked to the light on the ceiling, and it takes 30 mins to descend to the floor, spinning a dynamo in the light.
Seems too good to be true, wonder why the inventors seem to be having trouble finding financial backers, maybe they should ask Dragons Den.

 

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Dunno if the Gravity Light has been discussed here before but I just happened to see this youtube vid, a bag of rocks is hooked to the light on the ceiling, and it takes 30 mins to descend to the floor, spinning a dynamo in the light.
Seems too good to be true, wonder why the inventors seem to be having trouble finding financial backers, maybe they should ask Dragons Den.
For lighting a home it will be hard to beat buying several solar garden lights Walmart had them for 3 dollars each and not only will they give you free light for years but each one will recharge 2 AA batteries.

One of the best flashlights I have found and use now is the energizer solar crank flashlight. I had it about a year now and I usually use a flashlight for a few minutes at a time. I only used the solar panel once to charge it. Just crank it for a minute and you are good to go. It may have been someone on this site that recommended it, Amazon sell it for $16.20 but before you buy always read the customer comments they have.
http://www.amazon.com/Energizer-Sol...47&sr=8-1&keywords=energizer+solar+flashlight
 

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I read about the gravity light a few months back, is it in market yet? The idea was pretty simple - works like a grand father clock and since the need only a minimal amount of electricity for LED bulbs its suppose to be pretty good. I doubt its going to work for much more then getting around a room. I agree with the previous post - the $2 and $3 solar yard lights work pretty well for moving around the house after charging. The only thing is I don't believe you can turn them off and preserve their use for later in the night - its use it or lose it when the sun goes down. That isn't real convenient but it beats a candle I guess and the price is right. The energizer cranks are more power on demand which is good - just a little higher priced.

For serious contention though I don't think you can beat a full sized, 180/240 watt solar panel, inverter and battery charger. With the right stuff you can power up a notebook computer, e-reader, several flash slight batteries etc - its a little pricey and not very mobile but its always gonig to work - even on clowdy days you'll get some decent power output.
 

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Discussion Starter #4
I think the Gravity Light is aimed at poor third world villagers, but if solar panels or hand-crankers can do the job for the same price, they'd be a better buy.
And if it's just to light a simple mud hut I should think candles are as good and cheap as anything
 

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Just my 2 cents but for maximum longevity you want something with minimal moving parts. Solar panels over generators, like the Ripon said above a solar panel, inverter and batter charger. Since they have no moving parts, and if you use them below there rated capacity they should last a long time with the battery being the weak point in the link. Now the gravity light has many gears and I imagine the bag of rocks it putting them at their mechanical limit, if it is made of metal it would be to expensive and if it is made of plastic it would be to fragile. From what I researched the longest lasting system would be solar panel (should have 80% of rated capacity after 20 years and still be usable after 40 years) and Edison batteries (old technology but some are still going after 100 years). Of course the real long term system is nature itself it can provide you with everything you need to survive from food, water, heat, light and shelter.
 

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I dunno, I really like this technology and think it's a great idea. Me and Hank are currently looking at a way to do this on a large scale and power a home. With a big 3600 watt generator linked to a setup with some step-down gears and a lever system holding up a 700 pound weight....you might have something there.

In one of my novels (they are always horror, fantasy or sci-fi involving real physics) there is an inventor during the post civil war era who develops a 'gravity engine'- a perpetual motion machine that powers his shop. This was not purely fiction. There are documented cases of two men (Edwin and Guyes) perfecting an engine that was basically an artificial waterwheel- the big flywheel was turned by a chain or belt bearing scoops or troughs which was constantly fed by a tank above it that spilled huge amounts of water into the scoops. Like a modern toilet, this tank had a catchment tank below the scoop-chain to collect the spent water, and through a system of floats determined a high and low level mark that would trigger the clutch on a ship-style bilge pump. While the kinetic energy of the huge flywheel spun down, it would refill the upper tank and the process would pick back up to speed shortly after. If the water level was kept up the machine would not cease automatic operation without end. As a matter of fact, Mr. Guyes went on to build a small factory that was powered by a huge, fifteen-ton version of his chain driven model. Supposedly that thing was the modern equivalent of 5,000 horsepower- off grid, no fuel.
 

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Leon
Using gravity to run a generator, about the only way I can think of is a water fall or dam and use the force of water as all hydro-electric dams do. Remember in a perfect system 746 watts = 550 pounds raising or falling one foot per second so a 550lb weight 60 ft high would give you 746 watts for 1 minute.
 

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Leon
Using gravity to run a generator, about the only way I can think of is a water fall or dam and use the force of water as all hydro-electric dams do. Remember in a perfect system 746 watts = 550 pounds raising or falling one foot per second so a 550lb weight 60 ft high would give you 746 watts for 1 minute.
Say I could work out a way to run a transmission that stepped the work up by like 3:5300- I am thinking cuckoo clock style. Maybe have that system turn once an hour at one end and end up spinning a genny at 5300 on the output end. I am also thinking clockwork might be sexy for such an application. Hell dude, I don't ever want to say never...I seen giant machines like big ben run on it reliably and on down to the clockwork alarm clock which is still in use today all over the world. That's all this is in concept, the generator would probably look something like a big metal grandfather clock and spin a generator instead of turn a clock face. Even if the big thing only generated say 1/2 a kilowatt per hour, that would still be a friggin miracle in the winter, off grid, in the desert ect. Wind it up and the lights come on. OR say raise the main weight with a team of horses and power a farm all day...

The functional downside of this is that nobody has done one yet. It would require a skilled engineer and a lot of experimentation. In this day and age though, while we still have the modern world, we would have to build it now. Doing so off grid would be a BIG undertaking.
 

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Leon
I think you are pulling my leg About the only thing I have seen with that type of ratio is a cyclo-drive but I doubt they would work in reverse and you would need around 2600 ft/lbs of torque turning it once a minute.
 

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Discussion Starter #10 (Edited)
....the gravity light has many gears and I imagine the bag of rocks it putting them at their mechanical limit.
Yeah that rock-filled gravity bag looks awful heavy-


As regards waterwheels, this guy invented a neat little waterwheel 7 years ago but I've heard nothing about it since, I suppose the market's very limited because most people haven't got a brook nearby-



Waterwheel invention promises cheap electricity | Mail Online

PS- About solar panels, I'm no expert but i understand they can feed electricity into storage batteries on sunny days and even a trickle on dull days, but in a serious SHTF situation when the sky is greyed out for weeks or months/years (in a nuclear winter or volcanic dust earth-shroud etc), will the trickle be enough to keep say a light bulb burning forever?
 

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As to the Walmart solar yard lights, some of them are easy to pop the batteries out of if you want to save some power for later at night.
We used them during the last power outage we had.
 
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Great post, I'd like to see more mechanical solutions. Whether it is a perpetual motion machine or a grandfather clock style wind up device that runs a fan blade for ventilation (swamp cooler) Or high efficiency wind-up device. American ingenuity and persistence is still one of our strengths. Now if only we could stop selling out to china mfgs. and make the stuff here at home. Its hard for me to accept is better to make it abroad and ship it across the ocean to the U.S. I know our mfg. cost is more but it can't be more cost effective to outsource. Somebody is selling us out and its been going on for a long time.


punch
 
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