Indeed, and I am going to take a wild guess:  If you buy an "expensive" LED flashlight that costs $20 or $30, it contains a high-efficiency voltage-to-current converter, so that you can keep the LED flashlight at the same brightness and control the power consumption of the device as the battery voltage changes.  Hey, it might even make the LED flash at a high rate so you can save more power and it may even give you give you two brightness (LED current) settings.

Or, for a hundred bucks you can buy a Chinese Dollar-store flashlight that costs $1.664 in volume without the super high tech voltage-to-current converter.

You can perhaps make the antenna more efficient, but you still cannot harvest more than the energy that is actually available. So if there are 10 nW/cm² of ambient EM energy, with antenna efficiency of 90% instead of 60%, you get 9 nW instead of 6 nW, but it will still not recharge your battery.

Only good for the Whos down in Whoville.

Well it is indeed possible to make a self charging torch,although it would have to be a little more efficient than my setup. But non the less,it dose work,and dose self charge.

https://www.youtube.com/watch?v=tx3bpSKRuF0


Brad

Of course, if you do not mind running around with a football-stadium-sized device, everything can be done.

That was a 25 farad cap,and a very small antenna. If the antenna was around the outside of the torch body,along with a better circuit,you could charge a 1.5 volt battery within 5 hour's i would think,and get back 1/2 an hour of usable light.

It would all depend on the EM strength in the area you are in.
I would think out in the middle of nowhere,it would not work so well.

Brad

 author=txt link=topic=16003.msg475696#msg475696 date=1456567051]
First of all you have a coil there and we cannot know whether it did not pull the power from a nearby emitter, or simply from the EM field radiated by some wires running along, which is very likely. Take it to the backyard, to the street, or to a park, for a slightly more objective measuring. Then, if I understood correctly, you measured 0.175V at 0.003A - that gives the charging power of 525μW. For charging a single 1.5V cell (~3Wh), you would need 5700 hours (~8 months). For charging three AA cells and powering a 3W/120lm LED at full power during 3 hours (9Wh), you would need to charge the batteries during two full years. And that's only under the condition, that we ignore the limited efficiency of the charging, and the internal leakage of the batteries. Otherwise you would likely never finish.


Well i dont know what video you were watching Jr,but the whole recharging system dose work on pulling in the energy from emitted EM waves from a nearby radio station--so what's your point?.

Then, if I understood correctly, you measured 0.175V at 0.003A - that gives the charging power of 525μW. For charging a single 1.5V cell (~3Wh),

No,the system was drawing 3mA @ .175 volt's--that was not the charging current.

Harvesting man-made EM energy would be no 'free energy' anyway, because someone paid for the energy which powers the transmitter, and the RF field is weakened by sucking energy out of it so the receiver will need more energy to maintain the same field strength.

I have measured the voltage of the almost completely empty batteries:

#1: 1063 mV
#2: 1216 mV
#3: 800 mV, slowly increasing

Nice! Now it might be interesting to open the batteries and compare them to common NiMH batteries. Not that I would expect anything else, but just to be sure. Note: you'll need some protective gear if you decide doing so.

I don't expect any additional information from opening the batteries. I don't have a chemical lab to analyze the contents, and simply looking at it doesn't make much sense.
Additionally, in case they will offer a refund, this would not be possible after destroying anything.

Even if there would be anything special with the batteries, it might be impossible to detect this even by analyzing it chemically.
Example: If you would analyze p- and n-doped silicon you also would not recognize any difference, unless you precisely know for what you have to look.