Repair a Dead Power Bank || Repair and Replacement




About: I am Electrical Engineer who love to discover new things with the help of science and nature around me. I try to make it possible by seeing and imagining the things and finally converting them into practical...

One of my friend recently gave me a power bank which was completely dead. He is not using so he decided to gave me. So in this instructable i will show you how to repair such power banks with some repair and replacements. The batteries inside the power bank was corroded, so i tried to remove them out and gave a new life. I will share some simple tips in order to how to remove such corrosion even with home made solution easily available in our Kitchen. You can also replace new batteries for full capacity of power bank.

Small Introduction: Portable Power Banks are comprised of a special battery in a special case with a special circuit to control power flow. They allow you to store electrical energy (deposit it in the bank) and then later use it to charge up a mobile device (withdraw it from the bank). Power Banks have become increasingly popular as the battery life of our beloved phones, tablets and portable media players is outstripped by the amount of time we spend using them each day. By keeping a battery backup close by, you can top-up your device(s) while far from a wall outlet.

The Power Banks we're talking about are good for almost any USB-charged devices. Cameras, GoPros, Portable speakers, GPS systems, MP3 players, smartphones and even some tablets can be charged from a Power Bank - practically anything that charges from USB at home can be charged from a Power Bank - you just have to remember to keep your Power Bank charged, too! Power Banks may also be known as Power Stations or Battery Banks, too.

If you liked my project please CLICK Vote!

Lets Get Start!

Step 1: Disassembly

First Disassemble the power Bank carefully. You need to apply little bit of force but be carefull not to break the circuit board inside. Do not forget to take safety precautions.

Step 2: Checking for Problems and Errors

Here observing carefully in my case i found corrosion/rust over all my individual Li-ion battery . So in order to remove this use white vinegar and rub over the surface where corrosion/rust is present. This will clean the contact surfaces of the battery and now we are ready to solder all batteries together.

If you don't have White vinegar the you can do it via making your own solution .Follow these steps-

This process uses two solutions, one is regular table salt and vinegar. Any kind of vinegar will fine here. Its the acidity and corrosiveness of the salt and vinegar together that you want. The other solution is Sodium Bicarbonate/baking soda, and water. This is used to neutralize the corrosive properties of the other solution, and to further clean the battery terminals.

Step 1: Take off the Battries.

Step 2: Get 2 containers, one for each solution.

Step 3: Get 1 tablespoon of raw salt, and put it in one of the container. Fill up the rest of the container with vinegar, and stir the both together. Generally we put as much salt in the vinegar as will dissolve.

Step 4: Get 1 tablespoon of Sodium Bicarbonate(baking soda) and add it to the other container. Fill up the rest with water, and stir well. Add more baking soda to make it cloudy. The amount is not important, as long as it is alkaline to cancel the acid of the vinegar solution.

Step 5: Take the cotton ball or any cloth piece and rub over the battery terminal

Step 6: After 2 minutes or so, the terminal will look very shiny and new after appplying the vinegar solution. The acid and salt in the solution is etching away the oxides, exposing the bare metal. Make sure the metal is uniformly shiny. Leave it in longer if it is not perfectly clean throughout.

And you are done!! Shiny new battery terminals are ready for soldering.:)

Step 3: Plan for Repair and First Charging!

Check the Charging PCB with the help of multimeter, whether you are getting desirable output voltage or not. The nominal voltage of Li-ion cells is 3.6V-3.7V. I am getting output voltage of around 4.1volt that is enough to charge li-ion battery.

Now its time to solder the batteries. Unluckly while observing carefully i found that one of my four battery is dead because it was sweeled from the upperpart that simply means it wll not work. So i contuinuied my soldering part with just 3 batteries. Offcourse this reduced my Power bank capacity.

So lets do some Calculations over that.

Step 4: Calculation for New Capacity of Bank

In order to calculate overall capacity of bank we have to first determine the capacity of individual battery . So for this we have one formula:

Capacity of one cell(Battery)= Total Capacity of power bank / No of cells

= 10400 / 4

= 2600 mAh

That means the capacity of one cell is 2600 milli ampere hours(mAh)


2.6 Ampere hour(Ah)

New capacity of power bank = Capacity of one cell * No of cells working cell left

That is,

=2600 * 3

=7800 mAh or 7.8 Ah

Our power Bank capacity reduced from 10400mAh to 7800mAh.

Step 5: Packing and Testing

Enough Calculation, now its time to put all together. Pack the powerbank once again by installig batteries and other necessary parts.

Bring back the USB cable and Plug and finally just check weather powerbank starts cahrging or not. And wow we gave a power bank a new life with capacity of 7600mAh.

Step 6: Enjoy With Enough Power!

You can see after charging powerbank a little bit, it is now ready to use:)
You just gave a new life to a dead power bank;)

Now use and Enjoy.:D

This marks the end of this instructable. Hope you liked it.

Please vote for the project and share if you think it was awesome.

Don't forget to follow for more cool projects!!

YouTube channel:

Fell free to have any query. Hope you liked my instructable.

Share and Vote Thanks.

***If you liked my project please CLICK Vote! ^ Above ^ Thank You***



    • Tape Contest

      Tape Contest
    • Trash to Treasure

      Trash to Treasure
    • Arduino Contest 2019

      Arduino Contest 2019

    18 Discussions


    Question 19 days ago on Step 1

    When I conect power bank with mobile it showing negtavie chargng it means ?

    1 answer
    kavish laxkarrandipc

    Answer 4 days ago

    That simply mean you have interchanged the connection with +ve and -ve...So just interchange the connection from inside the power bank


    Question 3 months ago on Step 6

    Hi...myself krishanu...I had purchased ambrane power bank ...but the usb slots are not working several times I have given to change it..but no I want to buy a new body and a circuit for it..maa the batteries are ok...please tell me where to buy and how to replace it...


    Question 12 months ago

    How to remove the USB port? Please Sir


    Question 12 months ago on Step 2

    Sir I want to remove from the power bank


    Question 1 year ago on Introduction


    i have one doubt on New power bank.i bought a 10,000 Mah Power bank for mobile charging. but it is getting the input power instead of this not getting a full charge and not providing the output. it means its not giving charge to any mobile. in this circumstances what can i do..? kindly help me to solve this issue.


    1 year ago on Introduction

    I received a new White colour power bank I want to change it .I want to a brown colour power bank plz change it.


    1 year ago


    In case all li-ion cells were bad would it work with 3pcs Ni-MH 1.2V cells in series?

    Your help will be very much appreciated.


    1 year ago

    This is really sketchy. Your cells leaked electrolyte and yet you still reuse them. Replace the 18650s. Also If you want more veiws you should consider changing your title image


    1 year ago

    Those cells are not genuine 2600mah cells, their capacity is lower so final capacity would be lower, try finding panasonic 18650 with 3ah, that would increase capacity to 12000mah

    3 replies
    kavish laxkarCekpi7

    Reply 1 year ago

    Yes you are true we can increase or decrease the overall capacity of power bank. We cant say the actual capacity of complete bank without disassembling them.
    The more the individual capacity of battery the more the capacity of complete power bank:)
    Hope you like it.

    Cekpi7kavish laxkar

    Reply 1 year ago

    I like it, but i dont think you understand me, these cells that you have put inside are not genuine 2600mAh, their capacity is usually alot lower since these are probably chinese reused cells (look on youtube)

    kavish laxkarCekpi7

    Reply 1 year ago

    Yes they are not genuine .We can't trust manufacturers without looking inside. Also it seems that they are lesser than 2600mAh. Calculation i did here is for education purpose.:)


    1 year ago

    hello, i think that you can replace dead cell by 18650 li-ion.
    But I have never tested it

    1 reply
    kavish laxkaronion2

    Reply 1 year ago

    Offcourse we can change with new ones. But it even better if those old get newer life. We saved few boucks instead..:)