Xiaomi Redmi Note 5A Prime, released in 2017, has proven to be a reliable budget device, but time does not spare lithium-ion batteries. If your device began to quickly discharge, spontaneously turn off when charged 20-30% or inflated, then replacing the battery is the only effective solution to prolong its life.
The recovery process requires carefulness, as the body is made of metal and the interior is quite dense. The nominal capacity of the original BN42 battery is 3080 mAh, and the deviation from this value in a smaller way indicates the need for urgent intervention. In this article, we will discuss in detail each step of the procedure.
Before you start, you need to prepare the workspace and tools, and you need not only a new battery, but also a specific set of screwdrivers, because the screws in this model are different sizes and types of hats. Incorrect tooling can lead to damage to fasteners or failure of threads.
Diagnosis and selection of components
Before you start disassembling, make sure that the problem lies in the physical wear of the battery, and not in software failure or malfunction of the power controller. Check the usage statistics in the Settings → Battery menu, paying attention to sharp spikes in percentages or abnormally high consumption of background processes.
When choosing a new battery for the Redmi Note 5A Prime, it is critical to avoid cheap analogues of unknown origin.The market is full of fakes that can not only hold the charge, but also pose a security threat due to the lack of quality protection boards.
- 🔋 Original - marking BN42, 3080 mAh capacity, logo MI case.
- ⚠️ Quality copy – may have a capacity slightly below the declared, but stable operation of the controller.
- ❌ Cheap analogue - no protective markings, light weight, bloating after a month of use.
Pay attention to the date of production of the battery. Even if the battery is new, but has been in storage for more than two years, its chemical activity has already been reduced. Look for the release date marking on the plume or body of the battery itself.
Tools and training required
To successfully perform the replacement procedure, you will need a minimal but specific set of tools. Standard household screwdrivers may not be suitable due to the specifics of the screws used in the design of Xiaomi.
First of all, prepare a heating element. The glue holding the back cover softens at about 80-90 degrees Celsius. Using a hair dryer is possible, but a professional thermophen or pre-heater will significantly speed up the process and reduce the risk of damage to the display from local overheating.
- 🔧 Screwdriver kit: cross PH000 Torx T5 (squirrel).
- 🎴 Plastic mediators or shoulder blades for opening the body.
- 🌡️ Hair dryer or heater plate for softening glue.
- 🧲 Magnetic mat for sorting screws of different sizes.
Be sure to turn off your smartphone completely before work begins. Even when the battery is off, the battery is energized, and accidental short circuit of the connector contacts with a metal tool can disable the motherboard power controller.
☑️ Ready for repair
Rear cover removal process
The Redmi Note 5A Prime has an all-metal body that is glued around the perimeter, which creates additional difficulties compared to plastic counterparts, since the metal conducts heat to the adhesive layer less well and requires longer warming.
Heat the perimeter of the device evenly, paying special attention to the corners and areas around the camera lens. Do not hold the hair dryer at one point for too long so as not to damage the display or internal plastic elements. After warming up, insert a thin mediator into the junction between the frame and the cover.
⚠️ Warning: Do not try to cover the volume or power buttons, there are plumes and antenna inserts that are easily damaged by a sharp tool.
Swipe the mediator along all the faces, gradually unplug the lid. The movements should be sliding, parallel to the plane of the smartphone. If the lid does not respond, repeat the heating procedure without using excessive force.
What to do if the lid is cracked?
Disconnecting the plumes and removing the old battery
When the back cover is removed, you will see the internal layout, and the battery access in the Xiaomi Redmi Note 5A Prime is partially blocked by a metal plate and a main camera module, and you need to act consistently and without haste.
First, unscrew the screws that lock the metal protective plate over the plume connectors. The number can vary depending on the revision of the board, so carefully monitor the length of each screw when you twist.
| Component | Type of screw | Number of | Location. |
|---|---|---|---|
| Connector plate | Cross (small) | 4-6 pcs. | Central zone |
| Battery anchorage | Cross (medium) | 2 pcs. | The bottom part |
| Camera module | Cross (small) | 1-2 pcs. | Upper left corner |
Remove the plate and gently disconnect the main display plume and battery connector. To turn off the battery, you better use a plastic blade to eliminate the risk of short circuit. Once the connector is turned off, you can start removing the battery itself.
The battery in this model is glued to the frame on a double-sided tape. To extract it, you can use special pull strips (if they are preserved), medical alcohol to dissolve the glue or carefully warming the back of the smartphone.
Installation of a new battery and assembly
Before installing a new battery, you must carefully clean the seat of the residue of old glue and tape. The surface must be smooth and fat-free for the new battery to be reliably fixed. Use isopropyl alcohol and a lilaless napkin.
The new BN42 battery should be re-painted with two-sided tape if not applied by the manufacturer in advance, which will prevent the battery from shifting when the smartphone falls and the appearance of extraneous sounds (rattles) inside the case.
- 🧼 Degrease the seat with alcohol.
- 🩹 Stick a new Scotch on the case or battery.
- 🔌 Connect the battery connector before clicking.
- 🔩 Twisting all screws in reverse sequence.
Connect the display plume and check the device before final assembly. If the screen catches fire and the phone responds to charging, you can start fixing the metal plate and gluing the back cover.
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Use a B-7000 or T-8000 glue to fix the back cover. Apply it with a thin strip around the perimeter, avoiding getting inside the camera and speakers. The time for complete polymerization of the adhesive is 24 hours.
Primary calibration and verification
After the smartphone is assembled and the first switch on, the system may not display the charge level correctly, since the power controller has not yet “acquainted” with the characteristics of the new battery.
Discharge the smartphone until it is completely turned off (0%), then charge when it is turned off to 100%. After reaching full charge, leave the phone on charging for another 1-2 hours, this process will help the controller write new minimum and maximum voltage values.
⚠️ Warning: Do not use third-party applications to “calibrate” the battery, they only reset the statistical file in the Android system, but do not interact with the physical controller of the battery, and in some cases may even harm the battery.
For the first few charge-discharge cycles, observe the behavior of the device. If the phone warms up in the battery area when it is down or discharges quickly, there may be a manufacturing defect or a connector contact problem.
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A full calibration of a lithium-ion battery takes 2 to 5 full charge and discharge cycles. Don't expect perfect performance immediately after replacement.