18650 power bank soldering


Once I found out about the magic of the 18650 battery and the numerous power banks available I just had to order some. This power bank caught my eye because it had a power level screen and could output 2.1Amps so it could charge a table if needed.


What I didn’t know was that it wasn’t like all the other power banks because they didn’t have springs to hold the battery’s in place. I kinda felt cheated because the photos didn’t show the inside so you wern’t to know it didn’t have springs

Caution before starting

Before we get started, You can’t turn off a battery. I know this sounds stupid but you have to be very careful when dealing with lithium battery’s. They can explode so please be careful

Pre paring the battery’s

Now on with the installing of the battery’s. This isn’t the first time ive played around with battery packs that needed soldering. The hardest part about soldering battery’s is trying to get the solder to ‘stick’ to the battery. First you will need to remove the chrome from the battery’s.



The easiest way it to sand down the positive and negative terminal ether by hand or using a dremel if you have one. You dont need to sand them that much just so it removes the chrome. Once you have done all 4 battery’s you can move onto the soldering.

Soldering the batterys

Line up your battery’s with the positive terminal at one end and negative terminal at the other than strap them all together with some electrical tape like so.


The reason I strap the battery’s together is so they’re easier to handle and solder together.

cut some small strips of wire with the ends tinned and tin the battery terminal too. You will need to apply quite a lot of heat to tin the battery terminals so be patient and you might want to use a little flux


Solder each battery to each other like so. You will need to keep the solder to a minimum because it’s quite a tight fit in the enclosure.


Once you have all your battery’s soldered together you will need to solder a wire from the last battery to the respected pads on the PCB.



Remember to test the circuit out before we go any future in the assembly.


Like I said before it’s a tight fit getting it all back together. I found it easiest to put one said of the battery’s in first then pull the other side open and force it in, be careful with the wires because they can get snagged and pull off. Next up press the power button into place and don’t forget the LED surround then slid the PCB USB ports first then secure with the supplied screws.


Lastly apply the stick on-screen covers and your all done.


I thought I would test out the output voltage to see how close it was to 5v, As I suspected it was more like 5.15v


Also when the packs is not on it leaks 3.23v and the screen very faintly glows in the dark

But the good news is that it will charge an iPad out of 5v 2.1amp USB port



2 responses to “18650 power bank soldering

  1. Get some laptop pulls, usually one or two cells in the 7-9cell laptop battery goes bad, they are already matched and aged with each other…much safer than trying to use mix and matched batteries like that, still very cool build great job!

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