Powerbank / single external battery for small independent lighting or smartphone charging.
This tutorial presents the manufacture of a very simple powerbank allowing the feeding of a small lighting or the charging of a smartphone via a USB socket. It is made from lithium-ion cells recovered from used laptop batteries.
Lithium-ion batteries can be particularly dangerous. Their charges and discharges must be protected with a suitable electronic circuit. In addition, short circuiting a cell can cause it to explode: It is therefore imperative to handle them with care: gloves and goggles.
Removable computer batteries are mostly made up of lithium-ion cells in series or parallel with an input charge / discharge regulator. When a battery is faulty, it is very likely that only one of the cells or even just the regulator fails. It is still possible to reuse the others.
Why reuse this type of cells / batteries?
Technical data :
The realization of a powerbank from lithium-ion cells requires cell recovery as well as the acquisition of an electronic module charge / discharge. 2 options are available later:
The simplest option (explained in this tutorial) is the use of a single lithium-ion cell. This option requires only to validate the proper functioning of the cell by a voltage test.
The second option is to couple several cells together according to their load capacity. This requires more complex manipulation available ici.
Note: Safety equipment is to be worn throughout the realization.
Note: As a safety measure, pay particular attention to the fact that the "+" and -" of cells never come into contact.
1) The + of the cell is located on the side of the groove on the cell.
2) The minimum voltage reached by a discharged lithium-ion cell is 2.5V. If the voltage is lower, it can go to recycling.