Lemon Juice Batteries and Joule Thieves

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

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. 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!

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