Neat Gravity Powered LED Floor Lamp

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Re: Gravity powered LED light

Thanks for the link! That is a beautiful design, put that on the market around a hundred bucks and you would be a millionaire a dozen times over...

greener_gadgets_03.jpg
 
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Re: Gravity powered LED light

Lets calculate a little. The weight produces a force of 222,44N. Lets say it falls from 50". That gives about 175.151 Ws. Thats about enough to produce 800 lumens for a quarter of a minute :nana:
 
Re: Gravity powered LED light

Please don't use quasi sciences such as math to rain on this parade.
 
Re: Gravity powered LED light

I haven't RTFA'ed yet, but wouldn't there be significant loss to efficiency to get the weights back up to their starting position in order to continue producing energy?
 
Re: Gravity powered LED light

worldedit said:
Lets calculate a little. The weight produces a force of 222,44N. Lets say it falls from 50". That gives about 175.151 Ws. Thats about enough to produce 800 lumens for a quarter of a minute :nana:
Click to expand...

Close, but you should have gotten about 282.56. It's easy to get this from PE=m*g*h=(22.68kg)*(9.81m/s^2)*(1.27m)=282.56 Joules. 1 Joule/second = 1 Watt. Assuming 800 lumens from 10 LEDs is 80 lumens per LED at 1 Watt each, then 282.56 Joules of energy will be used up in 28 seconds.

But, it sounds like this device emits power while the weights are falling, so that 282.56 Joules of energy is not available all at once. If it takes 24 hours for the weights to fall (a complete guess), then 282.56 Joules has to be divided over the time (86400 s) to give 0.00327 Watts. It is complete and utter lunacy to think that this thing can produce 800 lumens! With 3 mW divided over 10 LEDs, we are talking about 10 micro amps per LED! You would be lucky to notice even the faintest of glows emanating from the LED dies. :candle:

I hope I am dead wrong about this. Please prove me wrong. I don't like to think that people are being deceived to this extent with pseudo-scientific inventions.
 
Re: Gravity powered LED light

mudman cj said:
If it takes 24 hours for the weights to fall
Click to expand...

4 hours is what the article states is the goal, but I am guessing they will need to do something closer to 30m to be able to get enough light for a desk lamp...
 
Re: Gravity powered LED light

mudman cj said:
Close, but you should have gotten about 282.56. It's easy to get this from PE=m*g*h=(22.68kg)*(9.81m/s^2)*(1.27m)=282.56 Joules. 1 Joule/second = 1 Watt. Assuming 800 lumens from 10 LEDs is 80 lumens per LED at 1 Watt each, then 282.56 Joules of energy will be used up in 28 seconds.
Click to expand...
Oh right. I hit the / instead of * button on the calculator. 28s are still not a really good runtime. Would be much better to power it with an AAA battery.
Dont they do such calculations before designing such a light?
 
Re: Gravity powered LED light

So assuming a 4-hour drop with the values given about, you're looking at just shy of 20mW... hardly the stuff of 800 lumen lamps even with great LEDs. Assuming it drops in 1 hour, you'd get 80mW... 30 minutes gives 160mW, etc... this thing can't possibly work the way they say it does. I love VT, but this is phony...

I wonder if they have considered exactly how much 22.68Kg is... that's as much as a small child. Hard for some people like the elderly to lift. The only people interested in this invention as it stands are environuts with a lot of money to blow.

800 lumens my foot. If this is what passes for science at our so-called "research institutions" then it's no wonder that so much bad science is published and taken seriously.
 
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Re: Gravity powered LED light

Here's my redesign of this idea...take an hourglass, put a small turbine in the flow of the sand (think waterfall powerplants) and use that power to light a high efficiency led. Tada....mini powerplant!

If anyone actually makes and sells this idea you better send me a dollar!
 
Re: Gravity powered LED light

Daekar said:
The only people interested in this invention as it stands are environuts with a lot of money to blow.
Click to expand...

Wow! Now that's a bold and very assuming statement. I can think of several very practical applications for such a light.

Think off grid areas where there might not be good enough daylight for solar such as Northern areas in winter. Think of the issue with batteries going bad current solar lighting and the fact that batteries no matter how good will go out.

I wouldn't call myself an environut by any means but the design, even if flawed at first, to me seems workable and practical. LEDs will be getting better and better and the design will be enhanced by such advances.

I have a gazebo back in the wooded are of my property and I've avoided running power to it for the issues of cost and hassle. Normally I bring battery powered light but this thing would be very useful there. Just crank it up (or lift or whatever) and forget. No need to turn off, no need to worry about running batteries down.

I'm sure there are plenty of people who would love an easy battery & solar free way to have some light off grid.
 
I saw this too. This article states 4 hours...

http://www.vtnews.vt.edu/story.php?relyear=2008&itemno=111

Cool idea. What if you had a 2 ton steel block on a fine thread screw with guide rails to hold the block from rotating. You force the screw to turn as it drops at a rate that gives you 24 hours of power and drives a generator. The generator continuously charges 3 RCR123s which are connected to a SF G3 which is pointed at a solar generator which slowly builds hydraulic pressure in a chamber sufficient to drive the steel block back up to the top, thereby resetting it.
 
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