Joule Thief Battery Charger

[Afrotechmods]

Problem is since the output voltage is completely unregulated and there's nothing in the way of charge termination you might end up popping your batteries. If you build this circuit keep an eye on the battery voltages and their temperature.

[senfdame]

1.  Build Joule Thief battery Charger
2.  Buy 1000 hamsters
3. ???
4. Profit!

[apepex]

Very helpful! I searched all the parts and it was too expensive, so I went to the local walmart and bought the energizer battery charger, took it apart and put it all together. It works great!

[Miata]

Instead of winding a coil you can use a pair of through-hole or surface mount inductors (look like resistors) & dirt cheap, For even smaller size and better control you can use a dedicated boost converter chip, no transistor, and just one inductor since it will pulse by itself. Look inside a cheap solar powered garden light to see how this is done.

[MrEunderhill]

I remember seeing a circuit like this in an electronics book years ago back before the internet was around. The main difference was a transformer was used to step up the oscillated DC voltage and then ran through a bridge rectifier.

[oldscoolgaming.]

I have been experimenting with charging two 1.5v AA batteries from 4 small, parallel wired solar panels all day.At the moment I have them joined up to a jewel thief, the volts seem to be creeping up slowly, even in quite low light.I have been looking for a way to improve the circuit, and yours looks worth a try.

[donaldsmith]

The cap after the diode isn't needed. In fact some think that a high frequency changing a battery helps batteries that are getting where they don't want to take a chance anymore because it can clean the surface of the inside parts, but I have not done any tests

[cinmay]

It would be nice to add some battery protection circuits to protect the battery against overcharging etc.

[gregorykusiak]

I’d love to know how to modify this circuit to use a 12v solar panel to charge 12v batteries

[neodiy]

How many amp does it produce cause it should produce at least 300 mA or more in order to charge a battery

[ralph]

Hi, What type of cap did you use for C-2 your output and what type of rectifier diode D-2 . I am going to attempt doing this of the glass of a USB plasma ball. I know it sounds crazy and I am sure a lot of people would ask me why do I want to do that, but I have found that there is a lot of power coming from the glass of a USB plasma ball and just for fun I want to find different ways to turn it into usable energy. I am sure that I will have to rectify the imput some since the 20 KHz frequency coming from the glass is like a very strong radio signal but like I said fun. I will share back on my results. Thank you.

[andrewfarley]

I have a small array of solar cells that produce around 2.5 v max. I want to be able to charge either a phone or battery bank, both of which draw 1A and 5v. Is there anyway this is possible as i built the circuit but my output voltage drops to basically 0v when the phone or power bank is hooked up. (It produces around 7V when nothing is hooked up to the output.)

[rossosrepairs]

could i replace the one 330uf cap with a parallel set up of 2 330uf 200v caps

[cyberstar]

is there a limit on the voltage input and voltage load? or does this basically double the voltage of anything going through it?

[unpackit]

Good Day!. what is the size of the wire that you have used;gauge

[kokoilie]

In the before schematic shouldn't the 1k resistor be between the transistor and toroid instead of being up there, or it doesn't matter as long as it's in-line with them?

[girishnimje]

Make what u have done is right i love it
but i think the schematic circuit u provided is wrong i have tried a lot but it does not work out for me n i did not get what the two dots mean near torroid

[realflow]

hook a joule thief to a speaker... any sound you make in the room at all will light an LED fully... lol.. use a capacitor to build up a charge on the output to help light an LED better.. Pretty close to free energy but technically not free. as the dust particles and air moving around in the room will make tiny vibrations touching the speaker. causing the tiniest voltage to be created..

[masbrosis]

gan rangkaian sederhana tanpa baterai output 3volt gmn gan?

[tedcerdania]

sir, is it possible to charge a six AA rechargeable batteries by a 2.3V dc source?