One day, I went to a forest region in India. I have charger but I am not having a power bank with me. In that forest I stayed in a tree house,there was no plug to charge my mobile. In such situation we can use this type of power bank. It is cheaper than the normal power bank. It can hold the charge up to 7 days. But there is a disadvantage in this power bank i.e it is an use and throw power bank and we can't recharge it.

Step 1: NEEDED MATERIALS

1.Cardboard

2. Aluminum foil

3. Blade

4. Cutter

5. Scissor

6. Non concentrated sulfuric acid

7. Insulating tape

8. Waste mobile charger

9. marker

10.Bowl

Step 2: CUTTING THE CARDBOARD AND THE ALUMINUM FOIL

Place the blade on the cardboard and the aluminum foil and draw the outline of the blade using the marker. Then cut those outline.

Step 3: SOAKING THE CARDBOARD PIECES IN NON CONCENTRATED SULFURIC ACID

Pour the non concentrated sulfuric acid in the a bowl and soak the cardboard pieces for 5 min.

Step 4: BATTERY

Take the blade and pieces of soaked cardboard and aluminum foil. Place the soaked cardboard on the blade and place the aluminum foil on the cardboard,again place the blade on the aluminum foil and place the cardboard and aluminum foil on it. Like that do it for 5 times.At last place a blade alone on the aluminum foil. Combine all those card boards, aluminum foils and the blade by an insulating tape.