getting more energy out of AA and AAA batteries

[Belfior]

Right!   

I guess I just learned more today about electricity than studying for 5 years...

[conradelektro]

But i changed to red leds to speed up the process.

Without any resistor, the 5 paralleled red leds were very bright, got warm and pulled about 136mA, so i dimmed them to about 4mA by using a 180 Ohm
resistor in the supply line.

Itsu

@Itsu:

I do not want to play the clever one, but one needs a 180 Ohm resistor for each and every red LED because no LED is exactly like the other and with only one 180 Ohm resisteor in the supply line they will shine with slightly different brightness. And the current draw will be greater with four resistors.

Four 180 Ohm resistors in prallel act like one 45 Ohm resistor http://www.1728.org/resistrs.htm . So the draw will be about 16 mA.

With a draw of 4 mA the test will last about 21 days (2000/4/24 = ~ 21), with 16 mA it will be about 5 to 6 days.

Thank you for doing the test, I can't wait to hear the result. I only have disk magnets and I would have to buy four somehow identical NiMH accumulators. The costs (magnets + accumulators) would be about 30.-- Euros which I do not want to invest in magnet-steel-power.

About LEDs http://dangerousprototypes.com/docs/Basic_Light_Emitting_Diode_guide :

"Connecting multiple LEDs in parallel is usually a bad idea. Even LEDs of the same production series have slightly different forward voltage to forward current ratios. Some LEDs will draw more current, and some less. This leads to differences in brightness between the LEDs that could reduce the useful life."

You probably know all this, Conrad

[itsu]

Conrad,

i would like to stay as close to the original setup, meaning 5 leds in parallel, so i toke only 1 resistor in the supply line.
The 5 leds are indeed shining with slightly different brightnesses, but i don't think it matters here.

I expect to see within a few weeks the result you and i expect to see, but untill then we will have to sit it out.

After a few hours stabilizing, the voltages are:
Magnet powered 1.753V
control               1.745V      at the leds.


Itsu

[conradelektro]

i would like to stay as close to the original setup, meaning 5 leds in parallel, so i toke only 1 resistor in the supply line.
The 5 leds are indeed shining with slightly different brightnesses, but i don't think it matters here.

I expect to see within a few weeks the result you and i expect to see, but untill then we will have to sit it out.

Ok, I get it.

As these things go, one could always argue that the magic ("electron pulling from steel by magnet") only happens slowly. Any "fast depletion test" would kill the magic. This is the age old problem that it is often impossible to disprove some claim. Any way, a 21 day test might be better than a 5 day test.

Greetings, Conrad

[itsu]

After 3 days:

Magnet powered  1.674V
control                1.714V      at the leds.


Itsu