getting more energy out of AA and AAA batteries

[itsu]

2 days ago i setup these 2 sets of 2x 2000mAH NiMh rechargeables in series, one set with magnets on top and a steel plate below them, and
a control set without any magnets or steel plate, see picture.

They are loaded with identical 5x paralleled leds which are barely glowing.

Starting voltage on the magnet powered batteries was 2.5V, and 2.514V for the control set,
now after 2 days 2.468V for the magnets powered batteries, and 2.505V for the control set.

Measuring the current via 4 different ways shows 4 different outcomes, so probably to low for proper measurements with the equipment i have.

Using my AC/DC current probe and my scope shows 0.9mA,
using a 1 Ohm precision resistor (csr) in the return line shows a noisy 4mA rms,
using my Fluke DMM at the 400mA DC range setting shows a steady 0.1mA,
using my Voltcraft analoge meter at the 5mA DC range setting shows almost no deviation, so probably also about 0.1mA.

Guess the meters show them best, so around 0.1mA.

I will leave the both sets running and monitor the voltage now and then to see what is going to happen.


Regards Itsu

[conradelektro]

@itsu: if a circuit uses 0.1 mA it will run 20.000 hours with a 2000 mAh battery. This leads to 20.000/24 = 833 days. Considering the slow self-discharge of the 2000 mAh accumulator, it might well run a bit more than a year. And it is questionable that this has anything to do with the magnets and the steel plate.

Your test will run for a very long time and will mainly test the rate of self discharge of the two accumulators. Therefore I suggest you use red LEDs which will light up at 2.4 Volt and will consume some milliamperes. One might even need a resitor of 100 Ohm for each red LED if the red LED has a forward voltage of 1.9 Volt and 5 mA is the desired current per LED.

We want to know whether the magnet has an influence in a convenient time span. And this alleged influence should not depend on the type of LED used. (While the type of  LED used, e.g. a white LED with a forward voltage of 3.2 Volt, has a strong influence on the current consumed by this circuit.)

It is well known that a white LED can glimmer (not shine) with a very low current (e.g. 0,1 mA) and at a lower voltage than its forward voltage.

Greetings, Conrad

[itsu]

Hi Conrad,

thanks for your reaction.

you are right, it would take ages for those leds to turn off.

Today measurement gave 2.485V on the magnet powered leds, and 2.502V on the control, so it seems the magnet powered batteries recovered somewhat.


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.

Measurements show:

magnet powered batteries 1.751V @ 3.8mA
control batteries               1.743V @ 3.9mA.


I expect the batteries voltage will climb the next days due to being drained (136mA) earlier, so will wait to they stabilize and remeasure.

By the way, the voltage measurement is across the leds, so not including the voltage drop across the 180 Ohm limiting resistor (180 x 0.0038 = 0.68V)


Itsu

[Belfior]

Hi Conrad,

thanks for your reaction.

you are right, it would take ages for those leds to turn off.

Today measurement gave 2.485V on the magnet powered leds, and 2.502V on the control, so it seems the magnet powered batteries recovered somewhat.


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.

Measurements show:

magnet powered batteries 1.751V @ 3.8mA
control batteries        1.743V @ 3.9mA.


I expect the batteries voltage will climb the next days due to being drained (136mA) earlier, so will wait to they stabilize and remeasure.

By the way, the voltage measurement is across the leds, so not including the voltage drop across the 180 Ohm limiting resistor (180 x 0.0038 = 0.68V)


Itsu

Just a small question about amperage. Would you say that amps tells you how much a circuit is transforming electrical energy to another form? People always say that Tesla coils can't output any power, because the output amperage is so low. I would argue that the machine is just efficient and the amps is a need that the load will introduce. If the load wants to transform X amount of amps into heat or light and the tesla coil will not provide this, then the load is "not powered". Then if you got a Gerard Morin type of generator&motor that will mostly just use voltage (very low losses) then you can easily power that with a tesla coil.

You can get the same amount of Lux from an LED with low amps and with a regular light bulb with high amps. This does not mean the PSU is more powerful, but the LED wastes less power into heat right?

[itsu]

Right!