Why one headphone Xiaomi discharges faster than the second: expert analysis

The situation of one headphone discharges faster than the second is one of the most common complaints of owners of Xiaomi wireless headset.Users often notice that the right or left module shows 10% charge, while its “brother” is still running at 60-70%.

In most cases, the root of the problem lies in uneven use times or the way you connect to your smartphone. However, ignoring this symptom can lead to a deep discharge of the battery, after which it will be extremely difficult to restore the device to work. It is important to understand the physics of the process: the lithium polymer batteries used in Redmi Buds and Mi True Wireless are sensitive to charge-discharge cycles.

This article is a technically sound guide to help you identify the cause of the imbalance and eliminate it.We will look at both software failures of the firmware and physical degradation of components so that you can extend the life of your favorite headset.

⚠️ Note: If the charge difference between the headphones is more than 30% after full charge in the case, immediately stop active use and proceed to diagnosis.Ignoring can cause the battery to bloat.

Physical causes and wear of batteries

The first thing to consider is the physical state of the food. TWS-Xiaomi headsets use miniature batteries that lose their capacity over time. If your headphones are more than two years old, asymmetric wear is a natural process. It is often the case that one channel (usually the right one, which is the master device) is loaded more heavily and goes through more charging cycles, which leads to a faster degradation of the cell chemistry.

The second important factor is the quality of the contact in the charging case, where the bottom of the seats and the headphone contacts accumulate oxidation, dust and earwax over time, which creates high transient resistance, which causes one of the headphones to charge not fully or very slowly, visually it may look like normal charging, but the actual indicator shows false data.

Temperature is also critical, because if you keep a case in your pants pocket or leave it in the sun, one earphone can get hotter than the other because of the design of the case, overheating accelerates the chemical reactions inside the battery, irreversibly reducing its life, check if the cover of the case fits tightly and if there is any mechanical damage to the case.

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Check the contacts with a cotton swab dipped in isopropyl alcohol. Oxidation is a common reason that one earpiece does not gain full charge in a case.

Software failures and controller calibration

Often the problem is not the physical battery, but the calibration error of the power controller. The battery management system (BMS) can misread the voltage, giving the wrong percentage on the smartphone screen, in which case a software failure creates the illusion of a quick discharge of one of the modules.

The calibration process involves completely discharging both headphones to the point where they stop turning on, and then charging them off for a long time.This allows the controller to re-determine the Li-Po capacity limits of the element. It’s also worth checking for firmware updates through the Xiaomi Earbuds or Mi Home app, as manufacturers often release patches that correct the logic of energy saving algorithms.

Another reason could be that the headphones are out of sync, and if the devices are out of touch, they can run in different power modes, and one headphone can try to keep connected to the phone while the other is in sleep mode, which is what causes the imbalance, and factory resets usually solve this problem.

Features of the Master and Slave modules

It is important to understand the architecture of your Xiaomi model. TWS-Headsets are divided into Master (leader) and Slave (subject) devices, although in new models with MiroConnect technology or analogues, this boundary is erased. Naturally, the module performing double work (reception) + Transmission, consumes more energy.

Usually the right earpiece is the master, but under certain conditions (e.g., if you get the left one first), the roles can switch. If you notice that the earpiece you take out of the case first is discharged, it's a feature of the connection protocol. In some use cases, such as when calling, the load is distributed unevenly due to the noise-canceling microphones.

There are models where one earbud is always the main one for touch commands. Constantly polling the sensor also contributes to charge consumption. If you use touch control on one side often, this earbud will run out faster. Check in Bluetooth settings if the smart ear detection feature is activated, which may not work correctly on one of the sensors.

Diagnostics through application and system logs

For accurate battery diagnosis, it is recommended to use not only the standard Bluetooth menu, but also specialized utilities. The Xiaomi Earbuds app (for MIUI/HyperOS) or third-party programs like Battery Charge Limit (require root) can provide more detailed information. Pay attention to cell voltage, if the application allows you to see it: a difference greater than 0.1-0.2 V indicates a physical malfunction.

Android system logs (Settings → About Phone → Version of the kernel, multiple taps) can find information about the power consumption of a Bluetooth profile. If one of the A2DP or HFP channels consumes an abnormally high amount of resources of the smartphone processor, this can indicate a bad signal and constant reconnection, which “sets” the battery of the headphone, which tries to hold the connection.

It's also worth testing in isolation, connecting your headphones to another device (tablet, laptop), if the problem is 100% identical, it's the headset, and if the other device is even, it's the Bluetooth module of your smartphone or its software.

Instructions for full reset and reconnection

If physical methods don't work, you need to perform a hard reset, which will remove all pairing profiles and return the headphone microcontroller to its original state. For most Xiaomi models (Redmi Buds 3/4, Mi True Wireless 2/3), the procedure is as follows.

Place both earbuds in the charge case and leave the lid open. Find the function button on the case (usually hidden or located on the end). Press and hold it for 10-15 seconds until the indicator flashes white or orange (depending on the model).

It is important to do the reset correctly, otherwise the configuration will not update. Make sure that the case is at least 30% charged at the time of reset, and the headphones sit tightly in the sockets. If the indicator does not respond, try charging the case for 30 minutes before the procedure.

adb shell am start -n com.mi.global.bcs/.activity.MainActivity

For advanced users: there is a possibility of resetting through ADB-commands if the headphones are connected as an Android audio device, but the standard button method is more effective 99% of the time.

⚠️ Warning: After reset, the headphones may behave like a new device. Make sure you delete the old Xiaomi Buds profile from your phone's memory before re-pairing, or the settings conflict may recur.

When repairs or replacements are needed

If neither calibration nor resetting nor cleaning the contacts helped to level the discharge, there was likely irreversible degradation of the lithium cell. The internal resistance of the battery has grown so much that it cannot hold the charge under load, in which case the software methods are powerless.

Repairs TWS-Xiaomi headphones are often economically inefficient, as the cost of the original battery and work can be up to 70% of the price of a new device. However, if the headset is warranty (usually 12 months), feel free to contact the service center. Asymmetric discharge is a guarantee if there are no traces of mechanical damage or moisture intrusion.

When you replace your battery yourself, be aware of the risks. Inside the headphones, you use batteries without overcharging protection (this is the function of the headphone board itself), and a careless opening can lead to a short circuit or fire. Use only a specialized tool and thermophen to soften the glue.

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If after 3 cycles of full calibration the difference in charge persists, it is a physical malfunction of the battery, requiring replacement of the battery.