Captret - Capacitor and Electret

[majkl]

oops, here's the right one. You dont need Spdt switch if you dont have one..

Just pull out the LED and hook up Cap - to anywhere on the side of the caps.

Hi hidave!
Your capacitors are in series, so the total capacity is less than a capacity of 1 capacitor (you have 4x 12000uF so total capacity is about 3000uF)
Have you tried capacitors in parallel? (total capacity will be 48000uF)

Do I need 250V capacitor if I want charge just 9V battery? Can I use 16V capacitor with the same capacity? Is it just about a capacity or about all energy the capacitor can store? (So the bigger capacity of capacitor and higher voltage means better results - faster charging ?!)
Regards
--michael

[e2matrix]

Can someone try this with NiMH or NiCd batteries.  I think you may find it does not charge if I'm right about the alkaline recovery effect.  Start with a NiMH that has been sitting a day or two.  If it goes up in voltage from this circuit then you may have something but with alkalines it does not say a lot.   

[ibpointless2]

Can someone try this with NiMH or NiCd batteries.  I think you may find it does not charge if I'm right about the alkaline recovery effect.  Start with a NiMH that has been sitting a day or two.  If it goes up in voltage from this circuit then you may have something but with alkalines it does not say a lot.

I have one of my captret self chargers running a 1.2 volt Ni-Cd 350 mAh rechargeable battery (the ones you get out of solar garden lights). It was left sitting for a week, the standing voltage on it was 1.138 volts. Now its up to 1.142 volts.

[void109]

I want to start with an apology.  I don't have time to read the pages of this thread I would need to, in order to catch up on where everyone is at with this subject.  I just want to share what I was looking at, where my intuition led me, just so I've thrown it out there, so to speak, on the off chance that this content is somehow useful to someone.

I had a notion that the two terminals of the capacitor, in conjunction with the case, were forming a series capacitance, and that what might be happening is we're tapping off of the midpoint of this series.

Others have said that it works with some capacitors and not others.  From my own testing, I found I couldnt get it to work from polarized electrolytic capacitors, but it the effect is present on non-polar electrolytic capacitors.  This, for me at least, added weight to my suspicion.

I then began hooking up various polarized electrolytic capacitors in series with reversed polarities for non-polar behavior and began tapping off of the junction between them.  I have seen similar (maybe identical, too pressed for time right now to be sure) behavior in this configuration.  It appears that if you draw power off of this junction, you will end up biasing the voltage distribution between the two capacitors, slowly.  When you remove the load, the slowly return to their original configuration (which draws current from the battery, I had several ammeters hooked up in various locations to measure the flow).

In a capacitor, is it the case that charge can slowly leak through the dielectric to balance charge?  If so, is it possible that this is all that is happening?  It seems like by tapping off of this midpoint you can draw current at the voltage rating present at the time, but the current draw is limited due to the behavior of the capacitors.  Which I think is interesting, because if you were to say limit the current using a resistor, you'd be dropping a significant portion of the voltage across the resistor instead of the load, whereas in this case you can apply the full voltage (apparently) but the current is limited.

Busy with my job right now, I need to make videos as soon as my schedule clears up a bit.  Thank you, please dont murder me for throwing sloppy research out there!   Gotta run!

[Groundloop]

@e2matrix,

I'm currently running a test with a 9V (actually 8,4V) NiCad, 150mAh.
I never could get this to work until I discovered that all my electrolytic
capacitors wanted to be positive at the can measured against the negative
terminal. So I used a ultra fast diode as shown in the attached drawing.
My NiCad has SLOWELY been gaining voltage from 7,36 Volt (yesterday)
to 7,56 Volt (today). I have no conclusions yet if the battery has gained
any real charge. One thing is for sure, I have repeated a shorting test of a capacitor
many times, and it always charge back to approx. 0,05 Volt. So the anomaly
of capacitor self charge is real. All my recharging tests with 9V depleted Duracell
batteries has been negative so far.

Alex.