Making a battery out of a potato isn’t exactly exciting. Most people have either seen it done or taken a class where they were forced to do it. Making a battery out of 110 pounds of potatoes, however, is something else entirely.
In a nutshell, potato batteries use the tuber’s phosphoric acid and the reaction between some zinc and copper to generate power. Boiling the potatoes as well as using multiple slices between the zinc and copper improves the generation.
The folks at BatteryBox decided to see if they could charge a phone (specifically a Samsung Galaxy S3) using a potato battery. In theory, doable, but the problem really became figuring out exactly how big of a battery they needed, and the actual work of building it.
In the end, the ludicrous endeavor required 110 lbs of russet potatoes, 36 feet of copper and zinc metal tubing, but they got it to charge. How effective was it? The battery gained five percent over five hours.
Useful in a post-apocalyptic pinch maybe, but you’re probably better of with a traditional backup battery.