How to make a 12 volt Battery Using 18650 lithium ion cell

How to make a 12 volt Battery Using 18650 lithium ion cell

I made this battery using 18650 Lithium ion cell, I used 3 cells to make this project 

I connect them in series connection And each battery nominal voltage is 3.7 volt and I use 3 battery so total voltage is 11.1 volt approxe.

So their is a question in your Brain how its provide 12 volte, because I mention in Thumbnail I will teach you to make 12 volt Battery.

So 3.7 volt is the nominal volt of battery and maximum voltage battery is 4.1 volt of this lithium ion cell

and connect the 4.1 volt of each cell in series connection and voltage is increased up to 12 volt

Components-

I used only 3.7 volt cell (x3)

A  PVC Pipe peace

A SPST switch 

And some peace of wire

Circuit Diagram -