@ Pirate:
    Three leds were connected in parallel on Koolers BwJt, I don't know if that has any relation to the diode plug (can't spell it) that you mentioned. 
  I think that there may be a point where a higher draw is better, so long as there is resonance.  His circuits are charging instead of discharging the battery. But the other device in the same video does not use three leds, just a single one, and he mentioned that it was brighter than the one with three leds.
  He also mentions that his device are constantly going from 1.2 volts down to 0.6 volts, and back up to 1.2v, and back down the 0,6 volts.
Has anyone else found this to be the case???

Quote from: NickZ on June 20, 2011, 12:30:14 PM
   @ Pirate:
    Three leds were connected in parallel on Koolers BwJt, I don't know if that has any relation to the diode plug (can't spell it) that you mentioned. 
  I think that there may be a point where a higher draw is better, so long as there is resonance.  His circuits are charging instead of discharging the battery. But the other device in the same video does not use three leds, just a single one, and he mentioned that it was brighter than the one with three leds.
  He also mentions that his device are constantly going from 1.2 volts down to 0.6 volts, and back up to 1.2v, and back down the 0,6 volts.
Has anyone else found this to be the case???

Can you provide the link(s) for Kooler's DUT that you're talking about here?  sounds very interesting.

With the sj1 circuit, after 15 hours of running on a single AA battery, the measured voltage is:
Start: 1.623 V
15Hrs: 1.621 V

Hope that is useful to you.  I will keep it running this way a while longer.

Quote from: NickZ on June 20, 2011, 12:10:53 PM
I was not aware that they can vary from about 1500 to 3000 mA.

One reason why most of the primary (non-rechargeable) cells have no rated amp-hours is - that the discharge characteristic is quite flat. (you have to specify a final discharge voltage)
Another reason is - that the consumable energy totally depends on the way you load the cell.
For a high dc current load (few hundred milliamps) - the consumable amp-hours can be a fraction of what you get with pretty less load (microamps).
If you load the cell with a pulsed load - for example pulsed microamps - the entire consumable energy can be a multiple of what the cell is rated for DC.
Conclusion:
A primary cell is no (huge) capacitor. (we exclude here electrolytic or super-caps- because they are effected by chemistry either)
The energy is derived from an electrochemical process with internal losses.
You can consume energy until this electrochemical process is exhausted.

Attached an example of a primary cell datasheet - duracell "AA" ultra.
You can find lots of datasheets for primary cells on the net.

rgds.

Quote from: xee2 on June 19, 2011, 07:36:38 PM
Very low power Joule thief. Video at >>  http://www.youtube.com/watch?v=KIQ2D1pqZNc

@Xee2-- a most fascinating circuit, Xee2.  I'm enjoying studying it on my bench.

I had one of the Goldmine toroids already wound with 14 turns of 22 gauge wire, so I used that.  (Good thing I bought ten of these toroids months ago, as they are out-of-supply now.)

R = 2.3 Mohms
MPSA06
Green LED and red LED that I have gave similar Pinputs, using the cap/time method.

Here is what I found exciting -- the operation changes dramatically with Vinput voltage:

2.8 V - 1.65 V, green LED is brightly lit at the start, dims then goes essentially out at ~ 1.65V.  Power consumption is quite high:

Einput = 1/2 C V**2

So Pinput = 1/2 C (Vstart**2 - Vend**2)/time

        = 1/2 10mF (2.8**2 - 1.7**2) / 3.4 seconds   = 7.3 mW = 7300 uW

Not too exciting so far, but I noticed that the LED came BACK ON at approx 1.63 Volts!  Not bright, but clearly glowing.  Note that Xee2 on his schematic specifies 1.366V as Vinput, so this would be in the range of much lower power consumption, Pinput.

Note that the power consumption is hundreds of times LESS:

Pinput = 1/2 C (Vstart**2 - Vend**2)/time

        = 1/2 10mF (1.431**2 - 1.243**2) / 200 seconds   = 0.0126 mW  = 12.6 uW  !!

The input power has dropped by a factor of over 500.
This is what Nick was talking about, there seems to be a "sweet spot" for operation.

BTW, I noticed the same pattern for the sj1 circuit a while back, dimming, then the LED comes back on and glows for a lot longer thereafter.  I thought it was just a curiosity when I discussed this with smartscarecrow last week, but now I see this as an important effect -- and very dramatic with Xee2's circuit, a huge reduction in Pinput.

With a red LED instead of Green, the Pinput is roughly the same (11 uW from 1.291V to 1.117V in 200s).  The red LED goes out at about 1.44 Vin (from the cap) and back on at lower Pinput, at about 1.406 Vin.

Now this is exciting -- but why the huge drop in Pinput at a critical voltage?? I really don't know, but would like to understand.  Will some of you jump and let's see if we can figure this out?  My GUESS is that the lower Pinput range is the most interesting in terms of seeking OU.

I checked with my DSO -- before and after the transition voltage to lower Pinput, the frequency of operation is about the same -- about 48 Hz for my build.  (21msec = Period)  But above 1.7Volts, we see that the pulses are large and pulsed DC, whereas below the critical voltage, the pulses are smaller but have a significant AC component. 

Thanks, Xee2! 

Quote from: NickZ on June 20, 2011, 12:10:53 PM
   Downunder and All:
   Thank you for the info on the AAs. I was not aware that they can vary from about 1500 to 3000 mA.  And the current is not shown on the batteries themselves. 
So, I'm afraid that unless we all use the same exact battery this test would not be very accurate either.
  But still, supposing that we use the most common and available AA,  a relative run time can be obtained.  A higher farad cap would also help. 
   The idea is to see if there really is any self-running aspect to this circuit, which can recycles the energy within the device, similar to the Joule Ringer.  And if that is not the case then, what advantage there might be over a regular Jtc.
   I personally feel that the additional energy that can keep a device running for months on end, does not come from recycled energy, but instead is drawn from the ambient.  But, that all needs to be proven.

I agree that a constant voltage and constant current is much more accurate.

Since constant current is a function of constant
voltage a voltage IC such as the LM431 @ 1.223V followed by constant current clamp will enhance the
battery source.  Being in agreement on this would allow comparison between two joule thieves so
illuminating battery drift.