Emergency Battery in the Wilderness

Step 3 Testing the Battery

Now when you take a light from a bycicle and connect it to the battery, it lights up! I don't have access to such a light at the moment, so I just tested it with my multimeter. In the picture below, i had the meter set on a range of 10 Volt, so as you can see it reaches 1,9 Volt, that's almost 1,5, which is the common battery voltage and used in almost all flashlights. I think you could use this battery in a flashlight aswell, but if you just remove one coin, aluminum, and paper towel(together one battery), the voltage will decrease a bit, because the batteries are in a series. So by just adjusting the length a bit, you can get the desired voltage! If you double the length, the voltage doubles aswell.

What you see is an electric current based on a redox reaction with copper and aluminum in a sour environment. If you're not familiar with redox reactions you can learn more about them here.