A battery and a banana are the same when considering energy:
A battery when connected to a device produces electro-chemical reactions and contains one or more cells. The same thing can be tried out with fruits also. There are many fruits which can be taken into account. A lemon shows less amount of voltage when seen through a multimeter rather than a banana which shows a higher voltage. This was because of the acid present in the a fully ripped banana. The acid is called ascorbic acid. This acid has a higher pH level than compared to the pH of the citric acid found in lemon.
This shows that a banana plant is not so expensive and reliable for the production of renewable energy and a battery is also inexpensive, reliable and stable.
