DIY battery cells are very exciting to make at home. It becomes more interesting if the raw materials are easily available and cheap to your wallet. In this project we will use water as the electro-chemical solution in which the electrodes will remain immersed. This cell works on the principle of ion exchange between the water and the metal electrodes. The salts and acids present in tap water migrates to the electrodes causing the flow of electron particles, thus yielding electrical power. Though the output voltage of this cell is too small, it is sufficient to drive a low voltage digital clock.
Difficulty level: Moderate. You may require basic knowledge.
Time required: The maximum time required for this project is 1 hour.
1. Two empty bottles or jars to store the water (capacity – 1 liter)
2. Connecting wires (one red colored, one black colored and the last one of any other color)
3. A low voltage digital display clock
4. Two copper leads
5. Two zinc leads
6. A thick needle to punch holes
7. A soldering iron
8. Transparent adhesive tape
Estimate cost: The average cost involved in this project is about $1-$2 (if you buy the copper and zinc leads).
- First, make the electrodes of the water cell. Connect the red wire, that is the positive terminal to a copper lead and the black wire or negative terminal to a zinc lead.
- Now use the left wire of any other color to connect the rest two pieces of leads. This interconnected electrode assembly is used to connect the two water cells in series in order to double the output voltage.
- Next, fill two bottles or containers with tap water and place them side by side. Punch two holes (with the needle) in each of the bottle caps for fixing the metallic electrodes inside the bottles.
- Now, insert the positive copper lead inside the left bottle and the negative zinc terminal inside the right bottle. Thereafter, put the zinc lead of the interconnected electrodes assembly into the left bottle (having a copper lead already) and the copper lead into the right bottle (having a zinc lead already).
- Take out the dead battery from the digital display clock and identify the positive and negative terminals very carefully.
- Next, connect the positive (red wire) and negative (black wire) terminals from the water cell to the corresponding points in the clock with the help of a soldering iron.
- Fix the clock to the bottles or any fixed support with the help of the transparent adhesive tape.
- You have completed making a digital clock powered by the electro-chemical energy of water. As soon as you connect the terminals, the display will flash up and show you time (you will have to adjust the time for the first time).
Frequently asked questions
1. How long will this water powered cell work?
Well, this one is going to work satisfactorily up to 1 month or so without affecting the display. However, if the water used bears more salt (varies from place to place), the cell will work effectively for a longer time. After that just change the water of the two bottles to recharge the cell.
2. How can I make this clock look attractive?
You can make use of a box, cut a hole in the front to mount the clock, place the bottles inside and color the outer surface to make it look stylish and beautiful.
1. Always use a low voltage digital clock for this project. It is because the output voltage of the water cell used here is very minimum. Thus, you should use a clock which uses very less power to run.
2. Change the water in the bottles at least once in a month to get best results.
3. Don’t use thick wires for the connections. This will cause the voltage to drop as a result of which your clock may not turn on.
Things to watch out for
1. Make sure that you don’t short the positive and negative terminals in any part of the entire circuit. This may damage the internal circuitry of the watch and ruin it.
2. Make sure that there is no leakage of water from the bottles, or they will flood your table.
3. Identify the positive and negative terminals at the back of the clock very carefully. Never connect the wrong wire to the wrong terminal.
4. Don’t forget to maintain the color code of the wires as described above. This will help you avoid any confusions. Always connect the red wire (positive terminal) to the copper lead and the black wire (negative terminal) to the zinc lead.