3D Printed 12000mAh Power Bank

Introduction: 3D Printed 12000mAh Power Bank

About: I'm a software developer who loves working on DIY electronics projects.

One can never have enough power banks!

I had a few LG HG2 18650 3000mAh cells that I wasn't using, so why not 3D print a case and make a beast of a power bank?! :D

Please Note:
This is NOT my design. All credit goes to
Kim3DIY for his amazing work!
Here is his Instructable:

Step 1: Tools Required

Here are the tools you'll need:

  • 3D Printer - I used my Anet A8
  • Soldering iron
  • Solder wire (flux core preferable)
  • Electrical wire
  • Glue Gun
  • Wire cutters
  • Screw Driver

Step 2: Components

Step 3: Print Parts

I used the following Thingiverse item:


Printed on the Anet A8 with the following settings:

  • Layer Height: 0.2mm
  • Filament: CCTree PLA 1.75mm
  • Infill: 10% - you should go higher - 20-30%
  • Print Temperature: 190/60
  • Print Speed: 60mm/s
  • Travel Speed: 120mm/s

Step 4: Solder Wires to Battery Holder

I used red for positive and black for negative.

Step 5: Solder Power Bank Module to Holder

Make sure you got the polarity correct.

  • The red wire should go to the BAT+ on the board
  • The black wire should go to the BAT- on the board

Step 6: Insert Batteries and Test the Module

Before you hot glue the battery holder and module into the case, insert the batteries to test if everything is working correctly.

Make sure you get the polarity correct!

You don't want to connect this cells in the wrong polarity - it will damage(burn) the module!

The cells are connected in parallel - all the positives will connect to the +'ve rail and all the negatives will connect to the -'ve rail.

Since they are in parallel and each cell has a rated capacity of 3000mAh, this will result in a total capacity of 12 000mAh!

Step 7: Insert Components Into Case

I had to sand down the reset button part a little and drill the hole in which it goes.

Other than that, everything should fit snug :)

I then used hot glue to secure the components and LCD

Step 8: Screw Lid and Print Labels

I used 4 x M3 screws to secure the lid on the case

I then used my label maker and printed some labels :P

Step 9: Done!

There you have it!

All you have to do now is wait patiently as it charges up.


It takes a while since the charging board only allows ~300mA of current to charge the cells. Unfortunately, this means that it'll take ~40 hours of charging from 0-100%.


The power bank has two ports, 1A and 2.1A. When you connect something the LCD will indicate which port you are using.
The module has a button which performs the following:

  • Long Press = Turn on/off the power bank
  • Quick Double Press = Turn on/off LED torch

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    5 years ago

    That is a nice looking powerbank! One question: shouldn't each cell be monitored/charged individually to prevent overcharging/over discharging?

    Yasthil Bhagwandeen
    Yasthil Bhagwandeen

    Reply 5 years ago

    Hi @ThomasBuildThis :)
    Thanks for the complement! :D

    You are correct! In this application, each cell isn't monitored individually for over charging/discharging. Since these batteries were brand new and all had approximately the same voltage when I connected them, they should be fine. The power bank module is essentially treating them as one large 3.7V 12000mAh 18650 battery. I could quickly remove the cover and charge the cells individually every few months - just for peace of mind. This wouldn't be ideal, but an option :D

    It would be a cool idea to add a balance charging port so I can balance charge the cells :)

    I'm also considering allowing another way to charge the cells. Charging at 300mA is too slow! :P
    Tempted to do this upgrade...

    Thank you! :)

    Yasthil Bhagwandeen
    Yasthil Bhagwandeen

    Reply 5 years ago

    I've been thinking about this and I think I made a mistake.
    I don't think you can balance charge the cells if they are in a parallel configuration!
    It'll only work if they are in series :)

    SerS 19
    SerS 19

    Reply 5 years ago

    Yup, I also think there's no way to control/balance batteries that are in a parallel config. And for that reason, the best bet is to buy them brand new and check they all have the same capacitance (mAh.). It is not a good idea to use the parralel config with any kind of batt unless you really know what you are doing. For example, a guy I know noticed a bad cell in his "bank" because that cell was always getting hot (due to overcharging).

    Yasthil Bhagwandeen
    Yasthil Bhagwandeen

    Reply 5 years ago

    Hi SerS 19,

    I agree 100% :)
    I used brand new LG HG2 3000mAh cells which I tested before connecting them in parallel.
    Yeah, these cells are really dangerous so guys must be careful when using them!


    5 years ago

    You actually didnt put random numbers as a clickbait, well done :)

    Yasthil Bhagwandeen
    Yasthil Bhagwandeen

    Reply 5 years ago

    Hahaha! :D
    Thanks @tutdude98! :)