I started work yesterday designing a AA and AAA battery charger using the new simplified joule thief with a low powered crystal battery.
I will probably do this in many parts and end up with a solar power option... I chose this project while I am waiting on my 1 mH inductors.
http://youtu.be/64gQubKk7x4

Here's part 2... http://youtu.be/-w9BR14vm-c
The cap charge is at 1382 after another hour...

Here's an update...it works, but not well enough... charging capacitor and first maintenance cycle for this little crystal cell #363.
http://youtu.be/QktI4Vp_2W4

Crystal Batteries #'s 362-365 Builds w/JT Circuits December 11, 2014
Dec 24 #363 - first maintenance cycle - Day 13
 - drilled hole, inserted 2 pinches of epsom, added water/straw/wick/glue/water

Here's another update. Not shown here, it is about 26 hours after the first maintenance cycle of this battery and the charge is showing
1193. We'll see how high it can get....

http://youtu.be/tO3K396ZntE

I am still waiting on some inductors for my next generation of crystal cells, so I am revisiting Jes Ascanius’ Version of
Nikola Tesla’s Aerial System. I thought a short video on how I use an LC meter to test components before the circuit
build might be helpful to some.

http://youtu.be/eNBr8a8i69o

This seems to be my best running cell so far... 17 days before first maintenance.. it's been running fine for 20 more days.... still running strong.
Crystal Battery #354 - Built Nov. 26
Nov 27 - 1.21 volts
Nov 28 - 1080 mV
Nov 29 - 1083 mV
Dec 01 - 1065 mV
Dec 3 -  1056 mV (7 days)
Dec 10 - 925 mV (14 days)
Dec 13 - 413 mV - added 3 mL of water - day 17
 - 1203 mV (day 0)
Jan 2  - 855 mC (day 20)

Almost forgot about this one... ran 26 days before first maintenance cycle and still running strong 12 days after that. Maybe this one is the
best. 352-354 were similar builds and are running on the same JT circuit design.

Crystal Battery #353 - Built Nov 25 (white LED - dry build w/Borax)
Nov 26 - 1066 mV - day 1
Nov 27 - 1105 mV - day 2
Nov 28 - 1054 mV - day 3
Nov 29 - 1084 mV - day 4
Dec 1 - 1050 mV - day 6
Dec 13 - 972 mV - day 18
Dec 14 - 903 mV - day 19 - disconnected JTC to create a better connection, then forgot to reconnect it...
Dec 18 - 989 mV - day 23 - reconnected JTC
Dec 21 - 446 mV - day 26 - no light (day 0 - maintained)
 - 961 w/no load, 0.8 mA on short, and climbing...
 - 1.01 mA after a few minutes and climbing
 - reached 1.09 mA after a few more minutes and began dropping
 - 890 mV w/no load after short and climbing
 - added 3 mL of water, quickly rised to 1600+ mV w/no load
 - shorted, it started at 19 mA and quickly pegged the meter to over 200 mA
 - set to the mV reading and it was showing over 1700 mV and climbing
 - reconnected JT circuit, 1200+ mV under load, climbing
 - after a few minutes, it is 1280 mV and still climbing under load
 - after an hour 1080 mV and 5.3 mA under load
Jan 2 - 987 mV - day 12

I am waiting for some single AA battery holders to build the final version of this and do a video, but here's the schematic.

Nice circuit.  Just use magnetic battery holders that you can easily build.  These work better and, they are universal and will stick to any size battery...AAA, AA, C, or D.  I have a video that shows how to make them.  It is cheaper than buying a limiting battery holder.  I get the feeling that you and I are alike in that money is tight for experimenting and this is a good savings.

I have never made a crystal cell but your work has me very interested in this device.  I followed Hutchison's work on this a while back.

Bill

PS  I invented these about 7 years ago and Lidmotor, in one of his videos, credited me with coming up with these universal connectors.
Keep up your good work.

re: https://www.youtube.com/watch?v=d31iEWBMh3M
Great video! I have done something similar, but it's kind of clunky at best in that the battery isn't stationed in one place.
The battery holders for AA's and AAA's are really cheap now. I have a full collection except for the singles, which I found for
$1.82 USD for 10 delivered, which is in my budget.. I don't know how they do that. It would cost me over $2+ just for postage
to mail something like that to someone in the US.

I started work yesterday on another version of that circuit to charge my lead alum batteries (about 9V) from a 12V battery bank.
I have built many SS SSG's, but I think a JT circuit would work just as well. I believe all that is needed for good battery charger
is pulsed DC. I have been working in the realm of 1/4 watt resistors for too long and bit the bullet yesterday to order some
2, 5, and 25 watt resistors. No more breaking out the calculator to run a bunch of 1/4 watt resistors in parallel! lol

Yeah... money is really tight, but it seems I can come up with a little here and there to get a few things. I am really struggling on
finding a reasonably priced source for magnesium and carbon. For example: magnesium sells on the futures market for a little over
$1 per pound, but the best price I can find is for magnesium rods, which equates to $28/pound. I don't get it, and at that price, I
can't get it. It would be really nice to have a bunch of 1oz bars of magnesium to play with, but I am guessing it would cost about
$10k+ to take delivery on the $1/pound magnesium on the futures market. That's the plan... don't hold your breath!

PS - today I am making a heat sink from an aluminum sheet I have here for my 2n3055 for this project.
I imagine it will be really ugly like my others... any suggestions?