Powerbank has become a device that can help to guaranty consistent supply of energy to modern electronics device ranging from mobile telephones, electric fan, home electronic appliances, to laptop computers.  The size of any power bank determines its area of application.

Though it is speedily gaining ground in many applicable areas, the use of mobile power banks for the recharging of smartphones appears to be dominating in number than other areas of application.

The reason being due to the consistent use of the smartphone to access the internet and carrying out other tasks using the phone.

It leads to speedy depreciation of the battery energy and the only way to keep such phone ON is by replacing the dropped power percentage using the mobile power bank in the absence of supply of any other form electricity.

Mobile Power bank
Mobile Power bank

Since it has become a norm and practically become a habit for many people using the mobile power bank for their phone and other devices, it has equally become necessary to discuss about it maintenance.

Mobile power bank comes in different sizes as well as different cells. The size and cell type determines its approach for maintenance.

This posts will guide you on how to carefully carryout a repair on damages that occur in any of them. However, we shall focus on the most popular type of mobile power banks using the LiFePo4 battery cells.

Mobile Power bank
Mobile Power bank

These days you will come across rechargeable radio set, MP3 player, and other these sets of appliances are using the LiFePo4 battery cells as its power bank embedded into the device.

Similarly, the repair approach of these appliances embedded power bank is the same with that of the mobile power bank we will be discussing here.

Procedures for the repair of damaged mobile power bank

The following are procedures you should employ in repairing your damaged mobile power bank:


Just like in every maintenance operation, the first operation is to carryout physical inspection of the power bank and ascertain if the actual cause of the power drop or damage is not from a disconnected wire or wrongly connected wire within the power bank or the USB cable connecting to it.

Get a multimeter and check for the presence of power in the power bank, if it still leads voltage and current then the problem will probably be coming from the cells and will need you to access the inside.

If no signal is received from the multi-meter it could mean a different cause of the problem and such will require further troubleshooting externally because it could be that the power bank is not receiving power during charging as a result of damaged charger or other sources.

At this stage there are many work to do just to be sure the fault requires accessing the inside. If it does require it then proceed to the next stage.


Without finding the fault externally using the testing tools at your disposal, you can proceed further to dismantle the power bank to search further and know the root cause of the problem. Carefully loose the casing and access the cells wrapped together that formed the power bank storage unit.

You can now proceed to the next stage.

LiFePO4 Cells and Multimeter
LiFePO4 Cells and Multimeter


Testing the cell of the power bank is the next action once you are able to access its power terminals. Use the multimeter to test the cells individually. In a normal situation you will be getting similar voltage range from the cells and the defective cells in their mist will give out very low voltage or no voltage at all.


Identify those cells that gave you poor or very low voltage during the testing stage and detach them out from the storage unit. Look for another LiFePo4 battery cells with the same rating of the ones that are good and use the cells to replace the detached ones.


Replacing the detached cells with news ones implies putting it back the way it was with the defective ones. This could require soldering operations depending on how the power bank was made. Work like this one is very tedious and requires a great deal of patience to get it right.

While doing this, you need to put the polarity of the cells into consideration, the positive + terminal should be soldered to the corresponding terminal the way it was with the cells you detached.

If you do not know the polarity of the cell use the multimeter to detect it by testing with the red and black terminals from the meter If wrongly placed the meter will read in negative direction in that case the opposite terminal is the true polarity of the cell.

LiFePO4 Cells and Multimeter
LiFePO4 Cells and Multimeter (reading negative)
LiFePO4 Cells and Multimeter
LiFePO4 Cells and Multimeter (reading positive)


If you have successfully made the necessary replacement of the cells, the next action is to assemble back the power bank and its casing. While coupling the power bank, be careful not to damage any soldered unit inside.

Also use proper wrapping for the cells and ensure there is no space inside the casing that permits the wrapped cells to move freely in case of fall or sudden shock. Equally spend time to couple the power bank properly using the appropriate coupling methods.


The next step is to test if the power bank is working as expected after the repair. Using its charger, plug it into an alternating current and allow it to charge for some time.

If the power range increased more than before then the repair was effective, but if it doesn’t work, then there is a mistake in the whole process and you may need to repeat it again.

Philip Nduka

Philip is a graduate of Mechanical engineering and an NDT inspector with vast practical knowledge in other engineering fields, and software.

He loves to write and share information relating to engineering and technology fields, science and environmental issues, and Technical posts. His posts are based on personal ideas, researched knowledge, and discovery, from engineering, science & investment fields, etc.

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