Xiaomi’s portable chargers have proven to be reliable travel companions, but even the best technology requires maintenance over time. The 20,800 mAh model is often heavily operated, which can lead to reduced capacity or mechanical damage to the body. Owners looking to extend the life of the gadget or replace the broken elements often wonder about the possibility of self-intervention.
You should immediately warn: opening the device automatically voids the official manufacturer's warranty. If your external battery is warranty-servicing and has visible seal marks, it is wise to contact an authorized service center. However, if the warranty has already expired or damage to the housing does not allow you to use the device safely, careful disassembly becomes the only option.
In this guide, we will take a closer look at the process of dismantling Mi Power Bank 2 and earlier versions at 20800 mAh. You will learn what tools will be required to work, how to safely disconnect the plumes and what to pay special attention to when working with lithium polymer batteries.
⚠️ Attention: Lithium polymer batteries contain high energy, it is strictly forbidden to pierce, bend at a sharp angle or heat the internal cells above 60 degrees Celsius, this can lead to fire or explosion.
Before you start to physically affect the body, you need to prepare the workplace. The ideal option is a table with good lighting and an antistatic mat, although at home you can also use a clean, dry surface without a pile. All the small parts are better placed immediately in a magnetic tray or container with cells, so as not to lose screws of different calibers.
Tools and workplace preparation required
The use of inappropriate items such as knives or sewing needles often damages plastic latches and scratches on the aluminum case. You will need a minimal but efficient set to work with Xiaomi Power Bank 20800.
The main tool will be a set of precision screwdrivers, most often in the design are screws with slits PH00 or PH000, may also need a flat screwdriver 1-2 mm wide to snap the internal clips, plastic mediators (poodzher) or old plastic cards are indispensable for opening the case without damage.
- 🛠️ A set of screwdrivers with magnetic tips (cross-haired) PH00, PH000 flat)
- 🔧 Plastic mediator or shoulder blade for opening (spudger)
- 🔦 Bright lamp or table lamp for illumination of internal components
- 🧤 Antistatic gloves to protect the board from static electricity
It's important to have good lighting in the work area, and inside the power bank case, there are small connectors and plumes that are easily damaged when visibility is low, and some craftsmen use a magnifying glass or binocular microscope if they have vision problems, because accuracy is critical.
☑️ Preparation for disassembly
Before starting work, it is strongly recommended to discharge the battery to a minimum, but not to full zero, this will reduce the risk of short circuits in case of accidental damage to the contacts during the dismantling process. However, storing a fully discharged lithium battery for a long time is also harmful, so the replacement procedure is better done immediately after preparation.
Design analysis and search for hidden screws
The Xiaomi Mi Power Bank 20800 external battery is all-metal, giving the impression of a monolithic design, and at first glance it may seem that there are no screws at all, as the manufacturer strives for minimalism and smoothness of surfaces.
In some revisions, screws may be hidden under rubber plugs in USB ports or under technical information stickers. In a 20800 mAh model, the most common hidden mount is under the decorative panel or in the recesses closed with rubber legs. Thermal exposure is rarely used, unlike smartphones, since the glue is used minimally.
The challenge is that screws are often covered with plastic plugs that need to be gently tucked in with a thin tool. Don't put too much effort into breaking the plastic. If the screw isn't visible, it may be hidden under a layer of glue or a sticker that you have to gently cut with a scalpel.
Where to look for the screws in different versions?
Once you've found and unscrewed all the visible screws, don't rush to separate the halves of the case. Make sure you don't miss the fastener under the logo sticker. Sometimes manufacturers hide one control screw there to prevent unauthorized opening. Use a flashlight by driving them along the shell seam to see the shadows from the screw hats.
The process of opening the body and dismantling elements
When all the screws are removed, the most important step is the separation of the case. Xiaomi Power Bank's aluminum halves are connected using dense seats and plastic latches. This is the perfect stage for a plastic mediator or a thin plastic card.
Start inserting the mediator into the joint between the top and bottom covers in the area USB-Move slowly along the perimeter of the device, and you'll hear the characteristic clicks, which are plastic clips, and the key here is not to use a metal tool that can slip and damage the battery or the control board.
Once all the latches around the perimeter have been snapped, gently lift the lid. Don't make sudden movements, as there may be short plumes inside that connect buttons or indicators to the main board. A sharp jerk will cause the contacts to break, which will require soldering to recover.
- 👆 Insert the mediator into the junction of the case at an angle 30-45 degree
- 🔊 Listen to the snaps of the opening latches around the perimeter
- 🚫 Avoid using metal blades to avoid short circuits
- 👐 Hold the body with both hands so as not to drop the internal components
⚠️ Attention: When you split the body, watch the plume of the indicators. In the 20800 mAh model, it can be glued to the inside of the lid. Unplug it slowly, without jerking.
Inside, you'll see two or four cylindrical elements (depending on the modification, in version 20800, these are often dual blocks) and a controller board. The board is usually fixed with screws or inserted into slots. To extract it, you may need to unscrew several more screws that fix the metal frame or the board itself.
Replacement of battery cells and work with the board
The main reason for disassembling power bank is to replace worn-out batteries. The 20800 mAh model usually uses 18650 elements. It is important to understand that simply replacing them with new ones is not enough: you need to consider the characteristics and method of connection.
The batteries in the bank are connected in series and parallel. When replacing, it is important to use cells with the same internal resistance and residual capacity. The ideal option is a new set of 4 or 6 identical cells from a proven manufacturer (Samsung, LG, Panasonic), using old batteries from laptops is not recommended, since their life is already exhausted.
Replacement of the elements will require spot welding. It is highly undesirable to solder batteries with a conventional soldering iron: overheating can damage the internal structure of the element and even cause it to swell. If there is no spot welding, you can use ready-made nickel tape and contact welding, or (with great care and rapid warming up) soldering, but the risk is great.
| Parameter | Original | Recommended replacement | Critical significance |
|---|---|---|---|
| Type of element | Li-Ion 18650 | Li-Ion 18650 (High Drain) | Only 18650. |
| Nominal voltage | 3.7 V V | 3.6. to 3.7 B | Not more than 4.2 V |
| Single-cell capacity | 2600-3400 mAh | 2600-3400 mAh | Same for everyone. |
| Max. Discharge current. | 10-20 AA | 10-20 AA | At least 10 A |
When installing new elements, pay attention to polarity. The repolyse during assembly is guaranteed to disable the charge controller, and the device will stop working. Check the connection circuit before the final assembly. It is also recommended to wipe the contacts with alcohol to remove oxides.
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Use a multimeter to check the voltage on each new element before installation. It should be in the range of 3.6-3.8 V. If the voltage is below 2.5 V, the element requires pre-pumping or disposal.
Device assembly and initial start
The assembly is done in reverse order, but requires even more care. Make sure all the plumes are stacked in their channels and not clamped by the body. The controller board should sit tight, without backlashes, but without undue pressure on the components.
When connecting the halves of the case, first snap one side, then the opposite side, moving towards the center. Do not use glue to fix the lid unless the design provides adhesive strips. The original Xiaomi Power Bank is held on screws and latches, which allows you to disassemble the device again if necessary.
After assembly, connect the device to the charger. Indicators should light up, showing the charge process. If the indication does not appear, check the connection of the plumes and the integrity of the fuse on the board (if it is available and available for inspection).
- 🔌 Connect a charger with a power of at least 2A for the primary charge
- 👀 Watch for indicators: they should flash or burn
- 🌡️ Check the body temperature after 10 minutes of charging (must not exceed 40).°C)
- 🔄 If the device does not turn on, repeat the connection check
The first charge-discharge cycle can take longer than usual. This is normal for calibrating a BMS (Battery Management System) controller. Let the device charge to 100% and then fully discharge it by plugging in a smartphone.
Common mistakes in self-repair
Even experienced craftsmen sometimes make mistakes, and newcomers to electronics repair can face unforeseen problems. One of the most common mistakes is to damage the plume when a sloppy autopsy is done. Thin conductors break instantly, and it's very difficult to repair them without a microscope and a soldering station.
Another common problem is the use of substandard batteries. The market is full of counterfeits that are labeled as 3000 mAh, but actually have 1000 mAh. Installing such cells will lead to the fact that the power bank will work unstable and quickly discharge. Always check the weight of the battery: a quality 18650 can not weigh less than 45 grams.
⚠️ Warning: Never close the battery plus or minus with metal objects.Short circuit causes instant heating and can lead to burns or fire.
Static electricity is also often overlooked. In dry environments, a spark of static can penetrate sensitive controller chips. Working in antistatic gloves or periodically touching a grounded metal object (for example, a heating battery) will help avoid this problem.
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The key to success is accuracy and the use of the right tools. Don't force the process if something doesn't unscrew or open, look for a hidden screw or latch.
Understanding these nuances will allow you to successfully repair and bring your portable battery back to life. Remember that each step requires calmness and concentration. If you feel insecure at some point, it is better to stop and consult a specialist.