Testing different electrolytes at home for DIY batteries.

For each DIY battery you make, you have dissimilar metals, like copper and zinc. But sometimes they are not always metal, like the aluminum foil and activated charcoal battery. In order to test the power output of different electrolytes we must make all other variables the same. Here's what you will need:

1. Penny
2. Nickel, post-1964 (1964 was a transition year so some nickels contain silver, get a nickel post-1964 to make sure it has no silver)
3. 2 wires each with an alligator clip.
4. Multimeter. If you want to use a USB meter instead you will need to buy this USB to test hook adapter.
5. 3 beakers or glasses. Plastic cups can work also. 
6. Salt
7. Vinegar
8. Lemon juice
9. Measuring spoon of 1 teaspoon
10. Measuring beaker of 100ml. If you don't have a beaker use a measuring cup for liquid measurements, not dry measurements.

Above: I use different containers, and I found a 60ml measuring cup!

Above: Find some wires with alligator clips on both ends. Hook the red wire to the nickel (+, red) and the black wire to the penny (-, black).

Now put 100ml in a glass, put both the penny and nickel in the water, and turn the multimeter to measure DC voltage. We get about 147millivolts with plain water, that's not enough to even light an LED.

Remove the penny and nickel. Now take the 100ml of water and add one level teaspoon of salt to it. Stir it well. Now put the penny and nickel back into the water. What voltage does the voltmeter read now?

If your multimeter reads a negative voltage it just means you have to switch the probes around. A negative voltage won't harm your multimeter. 

Remove the nickel and penny and add a second teaspoon of salt, stir it well. Put the nickel and penny back into the saltwater. How much voltage is being generated? How many amps?

Discard the salt water and rinse the glass well. Now make these solutions and test the voltage and amps they output. Write each result down.

1. 50ml water, 50ml vinegar. 
2. 50ml water, 100ml vinegar. 
3. Discard vinegar water and rinse glass well. 
4. 50ml water, 50ml lemon juice. 
5. Discard lemon water and rinse glass well. 
6. Add 100ml of soda. Take a voltage reading. Write it down.

What happens to the voltage and amps in each case? By adding more vinegar or lemon juice (both acids), does the voltage go up or down? What kind of voltage does soda give? Sodas are very acidic so they should work very well.

Summary
You can search the internet for different kinds of metals. Certain combinations of metals give higher voltages, and some give more amps, and some give a longer run time. Likewise, the stronger acids can also have an effect on voltage.