Archive | 23:59

Lemon Juice Batteries and Joule Thieves

1 Feb

To kick off February Project Month, I wanted to explore lighting LEDs with small voltages generated by lemons.   By using the evilmadscientist joule thief circuit, one can power a 3 volt LED from sources as low as 0.3 Volts such as dying batteries.   I wondered whether a joule thief could power an LED with low voltages generated by lemon style batteries.  To begin, I created a cleanly packaged design for a copper/foil battery that could reliably read 1V on the voltage meter.

I created an instructable on how to create my 1 Volt Cell from 2 Pennies and Foil.  The design uses dish soap instead of lemon juice which I found intriguing and slower to evaporate.

1V cell measuring 1.2 Volts on a Multimeter
1V cell measuring 1.2 Volts on a Multimeter

I then created my joule thief by following these instructions on How to Make a Joule Thief.  The video shows the entire process of building.

Joule Thief Working with 1.5V Battery

Joule Thief Working with 1.5V Battery. Click for more pictures.

The joule thief worked like a charm for regular batteries generating about 1.5V.  It appears however, that my 1 volt battery design did not source enough current to generate the required 3 volts in the joule thief’s inductor.  This experiment is still far from conclusive however because there are more efficient joule thief designs that utilize capacitors.  I will also try testing a similar penny battery design aimed to generate 1.5 Volts.

Comments and insight are welcome.  Thanks!