World's first real Free Energy Flashlight - no shaking - no batteries! No Solar

[Pirate88179]

       Well, the Ad that went with the promo info said $99, American, each.   That's what I saw.   As for reverse-engineering, the electronic engineer in my heart is intrigued by something that small that can produce light in effective quantities.   Now, from my experience, I'd power something with long-wire ambience harvesting with a step-down transformer, to a diode(s) and then to a capacitor; finally to a rechargeable battery.
       Now, for this application, the wire needs to be FINE.   I mean 45-50+ ga.   50+ would be better.   The transformer can easily be mounted on a PC board.   It needn't be very powerful, depending upon the power draw of the illumination bulb source.   Ditto for the capacitor, in voltage or capacitance capacity.   No battery.   The light bulb can be based on the LED, which can possibly(?) low power or low current type(s).
       In this way, by my personal experience, I see how this item can be built to provide performance on at least a minimum level.   IMHO.


Honestly.   Nothing against the character of  "txt", the originator of this text message I quoted.   I'm living in a rather stressful environment with homeless US Military Vets, and these guys can be a bit much to put up with.   I try not to insinuate an 'attitude' into my posted replies, but the ones I live with can put more pressure than I ever could and it can rub off, so to speak.


--Lee

Lee:

Have you not followed the testing results on these units?  They do NOT work as advertised and, as TXT said, you can buy a $2 light at any store that performs just as well.  It is a rip-off...scam...fantasy....

Bill

[Nink]

Lee:

Have you not followed the testing results on these units?  They do NOT work as advertised and, as TXT said, you can buy a $2 light at any store that performs just as well.  It is a rip-off...scam...fantasy....

Bill

Agree I think it is time we moved this one to the scam column but the concept  has peaked my interest a little bit.  Build a flashlight that will run for up to 3 hours a day and never go flat.

I think this is a interesting challenge with a lot of potential solutions.   

[txt]

I think this is a interesting challenge with a lot of potential solutions.

There may be some solutions, but EM energy harvesting is certainly not one of them, as long as you do not want to use any huge external antennas. The density of the available ambient EM energy is simply far too low in the average environment, including urban areas (let alone remote rural locations).

In urban environment (sample data taken in Tokyo and London), the ambient RF levels (all frequencies combined - FM, analogue and digital TV, wifi, ...) range between 0.2 nW/cm² and 1 μW/cm² (source: Ambient RF Energy-Harvesting Technologies). It would be even many orders of magnitude less for the Earth Magnetic field or Schumann resonances. For powering a 3 W torch for 3 hours a day (9 Wh), you'd need the charging power of ~400 mW. At a torch with the total surface of some 50 cm² and 100% efficiency, you'd get between 10 nW and 50 μW from the ambient EM field - that is four to six orders of magnitude less than you need. You'd need to collect the EM energy from 40 m² to ~200,000 m² to reach your goal.

Harvesting solar energy is a bit easier, but also not really realistic at those dimensions. Assuming you get ~10 hours of really strong light a day, and high grade solar cells, you may be able to harvest perhaps 2 kWh/m² = 0.2 Wh/cm² (that's irrealistically high in most situations, but let's count with that number). So for the 9 Wh, you need solar cells facing the sun with the surface of 45 cm² - that's already a bit closer to the dimensions of a common flashlight, but it would still need a rather bulky design. And in real world conditions, the surface area would need to be an order of magnitude larger, meaning you would need an external solar charger anyway.

[Nink]

There may be some solutions, but EM energy harvesting is certainly not one of them, as long as you do not want to use any huge external antennas. The density of the available ambient EM energy is simply far too low in the average environment, including urban areas (let alone remote rural locations).

In urban environment (sample data taken in Tokyo and London), the ambient RF levels (all frequencies combined - FM, analogue and digital TV, wifi, ...) range between 0.2 nW/cm² and 1 μW/cm² (source: Ambient RF Energy-Harvesting Technologies). It would be even many orders of magnitude less for the Earth Magnetic field or Schumann resonances. For powering a 3 W torch for 3 hours a day (9 Wh), you'd need the charging power of ~400 mW. At a torch with the total surface of some 50 cm² and 100% efficiency, you'd get between 10 nW and 50 μW from the ambient EM field - that is four to six orders of magnitude less than you need. You'd need to collect the EM energy from 40 m² to ~200,000 m² to reach your goal.

Harvesting solar energy is a bit easier, but also not really realistic at those dimensions. Assuming you get ~10 hours of really strong light a day, and high grade solar cells, you may be able to harvest perhaps 2 kWh/m² = 0.2 Wh/cm² (that's irrealistically high in most situations, but let's count with that number). So for the 9 Wh, you need solar cells facing the sun with the surface of 45 cm² - that's already a bit closer to the dimensions of a common flashlight, but it would still need a rather bulky design. And in real world conditions, the surface area would need to be an order of magnitude larger, meaning you would need an external solar charger anyway.

Hi txt
I am not sure if it is a single solution here or we have to limit ourselves to the "method" that ELFE stated.  I think the task is can we for <=$99 build a torch that meets the 3 hour a day requirement and not necessarily limit ourselves to a single self charging solution.   I think we are going to need a variety of energy harvesting technology to make this work.  You mentioned solar and EM harvesting as two options and these of course could be combined but could we also look at forms of energy harvesting, example peltier devices that use temperature difference (heat of bulb when running, internal temp versus external). Humidity harvesting that flex when moist and contract when dry.  I think if we give this a lot of thought we could come up with a variety of methods.    Energy optimization such as supercapacitors and Joule theifs etc could be deployed. 

I am not sure it would be a pretty solution or if we could do this the size of a typical flash light but I think we could first accomplish the 3 hour a day goal and then start to shrink this down to size of a flashlight we would eventually reach the point where it is possible.  At that point we could start to scale back up again, come up with solid state devices that combine all of the required energy harvesting into a single module (solar EM peltier humidity .... )

I am pretty sure if someone through a large bucket of money at this a 3 hour environment charging flashlight would be doable in 3 - 5 years and a 24 hour always on in light in 5 to 10 years.

[txt]

Even if you combine all those methods together, you won't get far. All besides solar and thermal is orders of magnitude lower, so it makes no sense combining it, making complex devices - it will be more cost effective focusing on increasing the efficiency of solar. Other sources of energy like acoustic, moisture, etc. will give you equally incredibly low levels of energy - check out the document I linked above - acoustic energy is also somewhere in the range of nW/cm³.

Thermal energy could be a bit more interesting, if you can get good temperature gradient, but that's not really attractive solution either. Recently I saw an article about a kid who constructed a hollow flashlight with the body made of Peltier cells. It is powered by the heat of the hand, cooled by air inside. The power you can get is miserable though, and it uses just a low power LED.

Miniaturizing is nonsense at energy harvesting, because the smaller you make the device, the less energy is available. You need to make the devices huge. You cannot extract more energy from the environment than there is available.

A supercapacitor does not generate energy. It is just an energy storage (similar to batteries). Joule thief does not generate energy either, it just dims the LED by impulses, so it draws less power. It does not add any power, it takes it away. If you want a more detailed explanation, have a look at this video, it is really funny: https://youtu.be/hoqF3gjLIyI