DIY 11200mA power bank with laptop batteries

Today I am going to make an USB power bank, using 4 laptop batteries. It happened that my colleague had 4 laptop batteries with 18650 lithium batteries. The 2800mA battery can provide very sufficient power. Now let's see the specific DIY process.

1. Remove the 4 18650 lithium batteries from the notebook batterys. At this time, a battery box is needed. After a round of online searches, I finally found a battery box that can install 4 18650 batteries, and it can provide charging functions and USB ports.

2. Open the battery box and you can see that there is already a PCB inside. The battery box can be installed with 4 18650 batteries.

3. The PCB in the battery box provides the functions of charging, discharging, power detection, protection circuit, etc. This also saves a lot of effort, and it is more difficult to make such a PCB by yourself.

4. Look at the interface again, the interface is still quite rich, you can use 5V power to charge or use USB to charge.

5. There is a power detection LED and a power detection button next to the battery box, which is convenient for checking the power level at any time.

6. Since the 18650 battery removed from the notebook is connected by a metal sheet, it is necessary to completely separate the 4 batteries.

7. Look at the information on the battery again. The battery is a 2800mA lithium-ion battery produced by Samsung, 4 pieces totaling 112000mA, which is enough to charge the iPhone4 four times slowly.