Power Bank Xiaomi 20800: step-by-step repair instructions

Xiaomi Mi Power Bank’s 20,800mAh external batteries are rightly considered among the most reliable on the market, and its aluminum body not only gives the device a premium look, but also provides efficient heat dissipation. But even the best lithium polymer cells degrade over time, losing their original capacity. If your power bank starts to discharge quickly or stops holding charge, replacing the internal cells can give it a second life.

The process of disassembling a monolithic aluminum case requires accuracy and understanding of the design of the device. Unlike plastic counterparts, there are no visible screws or latches, which often confuses users. The attachment of internal modules in the Xiaomi 20800 is carried out by fitting tightly into the aluminum pencil and fixing with plumes, not screws to the body. Violation of the integrity of the case when unsightly opened can lead to dents that will spoil the appearance of the gadget.

Before starting the dismantling, you need to assess the risks and prepare a specialized tool. Working with lithium batteries always involves the risk of short circuit or mechanical damage, which can lead to fire. In this article, we will discuss in detail the algorithm of actions that will safely extract the insides of the device and replace the spent batteries with new ones.

Preparation of the workplace and the necessary tool

You can't disassemble electronics properly without a properly organized workspace. You'll need a clean, well-lit surface, free of metal objects that can accidentally close the circuit boards. The main tool will be a thin metal blade or mediator, and a suction cup for working with dense enclosures. Be sure to prepare a plastic map or a special tool for snapping latches so you don't scratch aluminum.

To work with internal components, you must have a tweezer with curved ends and a set of screwdrivers, although this model may not have screws. It is critical to have a multimeter on hand to check the voltage at the terminals before soldering. If you plan to replace the elements, you will also need a soldering iron with a thin stinger, flux and solder, as well as insulating tape or shrinkage.

• 🛠️ Thin metal spatula or scalpel to open the cap USB.
• 🔦 Powerful flashlight to inspect internal connections and search for hidden elements.
• 🧤 Dielectric gloves to protect against static electricity and fat.
• 🔋 New 18650 battery cells with overheating protection.

⚠️ Warning: Before starting any work, make sure that the device is completely discharged or, conversely, has a minimum charge to reduce the risk of sparking in case of accidental closure of the board contacts.

Special attention should be paid to ventilation, soldering or possible deformation of batteries can release harmful substances, work in a ventilated room, away from flammable materials, Safety in this process is the number one priority, as a damaged battery can behave unpredictably.

Algorithm of opening of aluminum housing

The most difficult part of the process is to start disassembling without damaging the appearance of the device. The Xiaomi Power Bank 20800 housing consists of two main parts: the top cover with connectors and the bottom panel connected by pressing. USB-And there's a plastic stub that's held on a glue or a tight fit.

Carefully tuck the plastic insert with a thin blade or needle. Move around the perimeter, gradually freeing the edges. Don't use excessive force because the plastic can crack. Once the plug is removed, you will access the insides, but the main unit still sits tightly inside the aluminum tunnel. Sometimes, you need to gently tap the device on the soft surface on the opposite side to extract it.

If you can't remove the module with your hands, you can use a suction cup, attach it to the end of the inner block, if there's something to catch on, or you can carefully charge the board from the connectors. The main thing is not to deform the aluminum body, because it is almost impossible to straighten the dents on anodized aluminum without traces. The mechanical strength of the case depends on the integrity of its walls.

Dismantling of electronic boards and diagnostics

Once you remove the internal module, you'll see the controller's main board, which is connected to the battery cells via nickel tape or wires. A 20800 mAh model typically uses four 18650 elements connected in parallel, the board is fixed to a plastic frame or directly to the cells using double-sided tape.

To access the battery contacts, you need to disconnect the connectors or unfurl the nickel plates. Be extremely careful: short circuits of the plus and minus even on one cell can cause instant heating and energy release. Before weeping, be sure to isolate the contacts of neighboring elements. Diagnosis begins with a visual inspection of the board for swollen capacitors or traces of burns.

If there are no visual defects, go to the measurements. The normal voltage of the serviceable cell 18650 should be in the range from 3.0 to 4.2 Volts. Values below 2.5 V often indicate a deep discharge and irreversible degradation of the element chemistry. Xiaomi uses quality cells, but their resource is also limited by the number of recharge cycles.

Replacement of battery cells 18650

The process of replacing the batteries requires soldering iron skills. Old batteries must be removed by cutting off the nickel tape or carefully soldering the contacts. When installing new cells, polarity is critical. The mixed plus and minus are guaranteed to disable the controller board on the first turn on.

Use only quality cells from proven manufacturers such as Panasonic, Samsung, LG or Sony. Cheap counterparts often have real capacity at times less than claimed and can be dangerous to operate. Before installation, align the voltage on all new cells so that currents do not flow from one battery to another inside the assembly.

• ⚡ Clean the contacts of new elements with small sandpaper before soldering.
• 🔥 Use a fast-acting solder to avoid overheating the insides of the battery.
• 🧪 Treat soldering places with alcohol to remove flux residues.
• 🔒 Insulate the side walls of batteries with heat shrinkage or tape to avoid circuiting.

⚠️ Warning: Never try to solder directly onto the battery body while holding the soldering iron longer 2-3 Local overheating can damage the internal separator and cause the element to explode.

To connect the elements, it is better to use finished nickel tape and spot welding, but at home, neat soldering is also acceptable. The main thing is to ensure reliable electrical contact and mechanical strength of the assembly. After installing new cells, assemble the chain and check the total voltage at the output of the controller board before the final assembly of the case.

Device assembly and testing

The final step is reverse assembly. Make sure all the wires are laid properly and not clamped with the case. The board should sit tight, no backlashes. If the native tape has lost its properties, use the new two-way adhesive tape, but don't overdo it with the thickness of the layer so that the module enters the aluminum pencil.

Insert the assembled module into the body. It should enter with moderate force. Lock the end cap, applying a thin layer of glue around the perimeter, if necessary for leakage. Charge the device from the network to 100% and try to charge the smartphone from it. Xiaomi controller must correctly display the charge levels through the device. LED-indicator.

Notice the heating of the case during charging and discharging. Light heat is allowed, but the device should not burn the hands. If there is a strong heating at one particular point, immediately stop using and check the assembly for circuits. A properly assembled power bank works silently and steadily.

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Tip: After replacing the batteries, conduct 2-3 full charge-discharge cycles so that the controller is calibrated and correctly displays the real capacity of the new cells.

Frequently Asked Questions (FAQ)

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Proper replacement of power cells can increase the autonomy of your device at times, returning it the functionality of a new gadget for a fraction of the purchase price.