Salt water cell – Take 1

While I wait for all my electrode materials to arrive, I began my testing of the salt water battery system with what I have available.

My first test uses a carbon rod and a zinc plate. The result was a very small voltage; even after putting two cells in series this was only enough to light a single red LED:



I then tried to increase the voltage by dividing my system into eight cells in series:


This still only provided a few milliamps at 5.3volts


Back to the drawing board

The saltwater battery

A salt water battery is a wet-cell battery that uses salt water as its electrolyte. Normally wet-cell batteries use acids for their electrolyte. Car batteries use sulfuric acid – nasty stuff. The goal of this project is to to use safer materials than those found in normal batteries. Cadmium, Sulfuric Acid, Potassium hydroxide are all not good for the environment or for people.

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My research begins with trying for find out what the two electrodes should be made of to provide the most power out of the saline solution I have chosen. I have decided to work with salt water that has a similar salinity to sea water. I feel using elements and liquids that are commonplace will help people best understand what the battery is made up of. Lead and acids have nasty connotations.

The salinity of seawater according to wikipedia is around 3.5% salt
The salinity of seawater according to wikipedia is around 3.5% 


Finding information on what the best electrodes to use has proven to be much more difficult to weed through via research on the internet. Let down by hours of weeding through eco-friendly-energy-snake-oil, I decided to order samples of common electrode materials and test them in different combinations myself.

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Project Development – First Class

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    • Dream – My dream is to create a personal light that runs via a natural battery and includes a level of interaction that brings with it excitement and enjoyment to its owner. The goal of this light is for it to be an object that comes closer to eco-friendly than its plug-in counterparts. Additionally it should be more than just a utility ‘lantern’ source of light. I like to think of lighting as universal to everyone who can see. I want to design a light that can be used by any person anywhere on the planet. 
    • Vision – I would like this light to be powered by an electrochemical source that is less harmful to the environment than typical batteries. A simple salt-water battery or something organic in nature would be ideal. That materials that make up the enclosure should be more eco-friendly than just plastic as well. The light itself should be at least bright enough to allow its owner to read with. I have been experimenting with remote-phosphor LED lighting, and I think using blue LED’s to light a white phosphor plane would be a novel addition to the project.

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  • Goal – This semester at ITP I would like to build a working light that operates via an organic battery. The battery will power an LED array as well as a microcontroller that will adapt the output of the LED array in terms of mood and intensity for the user based on readings from a proximity sensor.
  • Plan –  (35% chance things go this way)
    • 2/10 – Research saltwater batteries and useable electrodes
    • 2/17 – Order and test different electrode materials to find the best combination
    • 2/24 – fine tune battery
    •  3/2 – fine tune battery and DC/DC boost circuit, research high efficiency LED’s
    •  3/9 – create LED array, research low energy atmel MCU’s
    •  3/23 – Decide on proximity sensor, proof with chosen MCU
    •  3/30 – rough draft of all circuity for project
    •  4/6 – finalize circuitry
    • 4/13 – Work on enclosure / form
    • 4/20 – Finalize enclosure
    • 4/27 – User testing, maybe build two
    • 5/4 – have at least two units built