Introduction: Double Joule Solar Thief All Contained in a Mint Tin

Picture of Double Joule Solar Thief All Contained in a Mint Tin

Charger of electronic gadgets, using AA rechargeable batteries, photovoltaic panels, and two thieves, two joule thieves that is.
All parts and components are recycled from old electronics broken yard solar lights. Only new parts are rechargeable batteries and thin coated wire for toroids.

This is my first Instructable so forgive me if it's rough, I will make every attempt to improve it, so questions comments and all constructive criticism is welcome and expected.

Step 1: What You Need

Picture of What You Need

photovoltaic panels- I got mine from old solar garden lights, that got run over by a car and wear only thing that did not crack
toroid-from old PC I got from garbage
L7805 voltage regulator, 1N4001 diodes, 2N3904 NPN Transistor- all from broken enlarger timer
miscellaneous wires from many broken things I horded

The only thing I buy is enameled wire, but you can reuse old CAT5 wire too.

And some sort of an enclosure for whole thing to fit in I used Altoids tin but I also wanted to use Apple USB Power Adapter box, Its clear so its awesome, maybe next project.

So My green twist is two twists. All parts wear, and can be for you, re purposed from broken, discarded electronic waist, And second twist It uses solar power to use however you like or want.

Step 2: Toroid Makeing

Picture of Toroid Makeing

Toroid making is not too complicated, winding two wires in pair through a toroid. At the end of winding there are 2 pairs of wires. twist together one of each of different colors and solder them together, other 2 wires are left loose

Step 3: Assembly of Joule Thieves

Picture of Assembly of Joule Thieves

i used 1N4001 and 2N3904 and have about 25 turns on my toroid

Step 4: Separating the Thieves

Picture of Separating the Thieves

one joule thief gets attached to photovoltaics other to usb

Step 5: Drilling and Glueing

Picture of Drilling and Glueing

drill through both top and bottom of a tin, use drill bit bigger then gauge of your wire, lace wire through and glue solar panels on tap and bottom of the tin I used double stick foam

Step 6: Rejoining of the Thieves

Picture of Rejoining of the Thieves

solder solar thief in to battery holder and battery holder to usb thief
solar thief is used to charge batteries, and USB thief to charge whatever your hart desire,

Step 7: Regulator You Mast Have a Regulations

Picture of Regulator You Mast Have a Regulations

L7805 voltage regulator and some creative soldering, and now I have 5V not 30+

Step 8: Compact It All

Picture of Compact It All

insulate all the connections and stuff it all in the tin, use double stick tape to hold battery holder in place

Step 9: All Must End

Picture of All Must End

last step insert rechargeable and wait for the sun to come up, Open tin for charging


Ghost Wolf (author)2009-06-23

Question can't you have it more portable by having it fold up without breaking the solar cell?

karlpinturr (author)Ghost Wolf2011-02-06

Folding the tin WON'T break the solar cell, as they are on the OUTSIDE - one on the top, one on the bottom.

In theory, you could charge the batteries with the tin closed, but unless you stood it on its end, you'd basically only get half the power.

The only thing you'd have to worry about breaking is the connecting wire between them - but just make certain it's long enough.

Ghost Wolf (author)karlpinturr2011-02-07

Yeah I see that's smart to have it that way I just thought it had to be folded out like that all the time.

cara se vc for montar dever colocar regulador de 5.2v para ñ queimar o celular, dispositivo, etc.

cara se vc for montar dever colocar regulador de 5.2v para ñ queimar o celular, dispositivo, etc.

cara se vc for montar dever colocar regulador de 5.2v para ñ queimar o celular, dispositivo, etc.

imrankhan110 (author)2012-02-27

From where did the regulator come in and do you join it and how come a cap ... whats all this. I mean please have a step by step instructor... 1stu copy some ones else diagram.. and u wantsus to follow... 2nd the regulator was required but how do u fit it in what abt the cap... Look dude iam a novoice to all this things till the time there is a step by step thing and clear diagram I cannot even think of statring it... please re do ur instructions and reload as its totally of no use atleast to me... Please help

TheSmurf (author)2010-04-30

I know NOTHING about circuits and diodes and all that shocky ouchy stuff... But is this page meant to be in another write-up? Completely ignoring this page I, and by "I" I mean my electrician brother, was able to build the charger and it works.
Someone pointed out that the voltage regulator you cited was wrong, indeed it was, the correct one is LM 7805 Voltage Regulator.
Also, could the author just clear up something for me, why are the USB parts sticking out of your tin the male parts? Things needing charging already have the male part, the charger should have the girly goods.
I am not knocking, please do not think that, I just think this article needs A LOT of cleaning up.

karlpinturr (author)TheSmurf2011-02-06

From a fairly brisk skim-through, it appears to me that the usb is actually an alternative method for charging the batteries IN the Altoids Tin, not for charging anything outside it...

wow dude im in 5th grade at 10 years old and i can do it without looking

dasimpson1981 (author)2010-09-29

they is a big problem with this unit that i see and have teasted
the solar panels to the joule thief dose sound a good idea but dose not work as expected.
yes it ups the voltage but in doing so you lose the ampage needed to charge the batterys.
i found i had to leave the batterys to charge for longer due to the little ampage comming out of the jt unit.
now connecting the solar panels direct to the battery with a diode inline to stop discharge thru the panels would be better.
also haveing the panels in parrale for more ampage and a single battery would be better that is if the usb jt unit will work correctly from the 1.5 volt to up it to the 5 volt needed.
now the joule thief from the battery to the usb seems a good idea if it works correctly.
running a secondary coil on the jt connected to the voltage regulator would be better if it works as this will draw less power from the bettery then if it would wired to the led output of the standerd jt

dasimpson1981 (author)2010-09-28

what is the cap there for also have you checked the aa batterys in a device to see if they do fully charge or not ?

lm13700 (author)2010-05-18

you should use a schottky diode at the output instead of the 1n4001
a schottky has a lower voltage drop

imakethings (author)2009-08-04

what is the final output voltage?

andrew101 (author)imakethings2009-08-15

5V. he used a voltage regulator. the second joule theif, if made correctly, can output well over 100 volts.

PirateLabs (author)andrew1012010-04-20

You can easily get over 2,000 volts from a well designed JT circuit using only a single AA battery.  I have been able to run over 400 leds from a "dead" AA battery.  Check out my videos on youtube for more on the joule thief circuit.

Great project, well done.


andrew101 (author)PirateLabs2010-04-20

cool whats your channel name?

PirateLabs (author)andrew1012010-04-20


It is:


If you have any questions, jet let me know.  Check out the Joule Thief topic over at and you will see many great variations on this circuit.  I thought I was doing some nice things with it but these folks really have gone beyond anything I would have thought of.  I am still learning and also I like to share what I have learned, which is how I learned.


botronics (author)2010-03-19

Funny how your schematic drawing does not match you work, but looks a lot like mine! You can draw your own schematics by downloading ExpressPCB schematic for free at

flying pie (author)botronics2010-04-18

because its yours

TheSmurf (author)2010-03-11

So cool!

knektek (author)2009-12-28

is this basically increasing the voltage and then dropping it again?

blackdogg (author)2009-12-10

there is anough place to put the solar pannels in the box too, so it wont break in your pocket like mine...

808create (author)2009-09-26

It seems that I've seen what looks like a joule thief on circuit boards of various electronics I've vivisected over the years. Can they be re-purposed?

808create (author)808create2009-09-26

I just looked at my defunct 3 year-old HP motherboard, and there are 2.

ironsmiter (author)808create2009-11-23

The PARTS for a joule thief are usually available in most electronic gadgets.
but with the exception of solar garden lights, very few complete JT circuits are present.

They can be re-purposed fairly easily. In fact, most of my joule thief components have come directly from ancient(p2 and older era)defunct laptops. The newer laptops tend to have surface mount components that are difficult for me to work on, without proper magnification(which I don't have in my "recycled electronics" shop area).

I THINK what you are refering to, that you found on t HP motherboard, is the ferrite cores. The types and sizes of core vary, but all will work in a JT circuit. you may just not have optimal efficiency. Usually not a problem though, as you're STARTING with "dead" batteries otherwise destined for the recycler. Wasted 'free energy' is still free.

ironsmiter (author)2009-11-23

L7805 has a max input voltage of 30V....
we've been discussing this chip on another 'ible.... :-)

So, selection of components and toroid winding are somewhat critical, as the USB output joule thief can EASILY overvolt the L7805.
For long term operation and reliability any how.
It's a fairly robust chip, and properly heat sinked, can survive much greater adversity than it's spec sheet lists. especially at such low currents.

adnimo (author)2009-09-27

you should use heat shrink tubing next time, chances are the electrical tape will fail eventually, specially with the irradiated heat from the sun. also, try using a germanium diode as well, they have lower breakdown voltage (a third of silicon's), using a germanium transistor will also help you obtain high output with lower input but they are relatively hard to come by in some places.

theseventhsage (author)2009-08-30

Please give any suggestion to the "Instructables the Movie" at

fransch3 (author)2009-08-19

This section is not very clear is there any chance of a diagramme

imakethings (author)2009-08-17

can i use a 4v 150ma solar panel?

codex653 (author)2009-07-17

good job! i like it!

aceopspadeshearts (author)2009-07-12

Its LM 7805 by the way ...=)

toxicgasleak (author)2009-06-28

Can anyone give examples of common items I can use as a toroid?

hominid (author)toxicgasleak2009-07-06

Compact flouro lights have them inside if you have a broken one, or defunct computer power supply.

fabrivassa (author)2009-06-11

It's 'were' non 'wear'

nunepi (author)fabrivassa2009-06-11

sorry and thank you I'm a ESL so I i do that some times

fabrivassa (author)nunepi2009-06-11

well, I'm not even English! :D

bigredxyz (author)2009-04-20

excelent project but i'm a little confused here... is the power given to the usb independent of the batteries?? if so, how are you regulating the voltage? i thought joule theifs output around 50V. great idea none the less

The Wolf (author)bigredxyz2009-05-23

hmm you could charge 5+ usb devices at the same time

nunepi (author)bigredxyz2009-04-20

Hello I'm not an engineer I'm more like a tinkerer. So there will be holes in my reasoning and design. But you right, regulator is needed, I will make amends.

godsfshrmn (author)2009-05-14

I'm completely new to all of this. What is the purpose of the transistor and toroid? What prevents the AA from overcharging? Thanks!

nunepi (author)godsfshrmn2009-05-14

some things did not work the way i was thinking they would, so I'm redesigning and will post updates

Yerboogieman (author)2009-04-25

You should take a picture testing this with a multimeter.

nunepi (author)Yerboogieman2009-05-04

I got busy. but yes I just got my multimeter will add results soon

laurensickles (author)2009-04-22

youre my idol this is so cool

tsaylor (author)2009-04-21

Does the solar charge the batteries and the usb device as totally separate operations, or does the usb charge from the solar and the batteries?

nunepi (author)tsaylor2009-04-21

solar charge batteries, batteries are connected to usb thru joule thief, there are no on/off switch on solar so technically it is connected to usb too , I need to add voltage regulator for usb, will do it today and update also need new schematics

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