When the external battery Xiaomi Mi Power Bank 3 20000mAh charges unnaturally long, often puts users at a loss. a device that should be ready to work in a few hours, can remain in "charging" mode for more than a day or not to gain capacity. This does not always indicate a breakdown of the energy storage itself, but you can not ignore the problem, as it can indicate wear of the elements or a malfunction of the control controller.
In most cases, the reason lies in the incompatibility of the power supply used or damage to the cable. Xiaomi power banks support fast charging protocols Quick Charge 3.0 and Power Delivery, but activate them only if the appropriate equipment is available. If you connect the device to a normal USB-A computer port or a weak 1A adapter will take a long time to recover.
Next, we will discuss in detail all the technical aspects that affect the rate of replenishment of energy, you will learn how to distinguish the software failure of the controller from the physical degradation of lithium polymer cells, and what steps you need to take to restore normal operation of the gadget.
Previous articleThe Anatomy of Charging: How Xiaomi Power Bank 20000 Works
To understand the delays, you need to understand the architecture of the device: Inside the case Xiaomi Mi Power Bank 3 are three high-density cells, each about 6660 mAh, connected in series or in parallel depending on the modification, the total energy consumption is 20,000 mAh (74 Wh), which is a significant volume for portable electronics.
The charger is controlled by a dedicated chip controller that supports two-way fast charging, and Negotiates (adjusts) voltage and current with the adapter connected, and if handshake is not passed, the system goes into safe mode with minimal current, which leads to a 3-4-fold increase in charging time.
Technical details of the controller
Inside the device, a Texas Instruments chip or similar is used to convert voltage and protect against overheating. It is she who decides to go into fast charging mode.> It is important to understand that the declared full charging time (about 4.5 hours) is only relevant when using the original power supply with support for 27W or higher. Using standard charges from older smartphones can increase this time to 10-12 hours or more. The effect of the cable and power supply on speed The most common mistake of users is the use of poor-quality or too long cables. The resistance of the wire directly affects the voltage drop. If the cable is thinner with a 1.5 meters or has a critical charge length, the controller can also play a role of the power supply. Adapters with less power 18 WWs will not be able to physically charge the battery with capacity 20000 Moreover, some cheap power supplies have unstable output characteristics, which causes the Power Bank controller to constantly reset the connection and start the negotiation cycle anew. 🔌 Use Type-C to Type-C or Type-A to Type-C cables with the label 3A or 5A. ⚡ The power supply must support the protocol. QC 3.0 or PD 2.0/3.0. 📉 Avoid cables longer than the length of the cable. 1 Just a meter to quickly charge large tanks, check the connectors for oxidation or dust, even microscopic contamination in the port. USB-C It can prevent the contacts responsible for transmitting data about the charging protocol from contacting tightly, leaving only the lines of force. The internal logic of the Xiaomi controller is programmed to protect the cells, if the temperature inside the case exceeds the permissible norms (usually higher). 40-45°C), the system forcibly reduces the charging current or completely stops the process. In winter, the situation may be reversed. 0°C chemical reactions within the element are slowed down and charging may become impossible or extremely slow.The controller will not apply high voltage to the cold battery to avoid loss of metallic lithium and irreversible damage to the structure. ⚠️ Warning: Never leave the overbank to charge in direct sunlight or on heaters. Overheating is the main enemy of the durability of Li-Pol batteries. The optimal temperature range for fast and safe charging is from +10°C +30°C. If the device is hot to the touch, let it cool before connecting to the network. If external factors are excluded, the problem may lie in the degradation of the battery cells themselves. Over time, the internal resistance of the battery increases. The controller, seeing a sharp surge in voltage when the current is applied, may mistakenly interpret this as a full charge or malfunction, cutting the process. For diagnostics, you can use the "pumping" method. Fully discharge the device (before turning off the indicators), and then put on a low-current charge (for example, from a USB port of a computer) for 1-2 hours. After that, switch to a powerful power supply unit. Sometimes this helps the controller to readout. Symptoms Possible cause Indicators Blink Short circuit or overload Disconnect load, check cable Charging goes up to 50% and rises Degradation of one of the cells Replacement of elements or recycling Strong heating of the case Controller Failure or KZ Stop using dangerous! Charged only in the off state Software failure logic Full discharge and long charging Software failures and the need to reset Although in Xiaomi Power Bank there is no operating system in the usual sense, the controller microprogram can malfunction. Sometimes short-circuiting (for advanced users with a multimeter) helps, but it is safer to use natural discharge. Frequent use of the function of "small current mode" (for charging headphones or fitness bracelets) can also affect the logic of operation. Make sure that you do not activate this mode accidentally with a double-press of a button, since it limits the output current, but should not affect the input. When it is time to think about replacing the device, the Lithium-polymer battery resource averages 500-800 full charge-discharge cycles. If your bank is more than 3-4 years, the controller is actively using this indicator, it can safely stop using this charge. Even if the device continues to work, the risk of fire or chemical burn becomes critical. Li-Pol elements are not repaired, they can only be replaced, but in monolithic cases Xiaomi it is often economically impractical. ⚠️ Warning: If you notice that the body of the superbank has swelled and stopped lying flat on the table, immediately dispose of it. Modern models are highly energy efficient, and if an old device charges for 20 hours instead of 5, its efficiency drops dramatically. Most of the energy goes to heat, not to storage. FAQ: Frequently Asked Questions: Can I charge Xiaomi Power Bank 20000 from a laptop? Yes, I can, but it will be very slow. USB laptops usually give a current of 0.5A or 0.9A. For a capacity of 20,000 mAh, this will take more than 24 hours. Also, a laptop can sleep or limit port power to save its own battery. 100%, But the phone is not charging enough, and that's a sign of a memory effect of the controller or a battery degradation. 3000 mAh is 100%. It requires calibration to discharge completely. Is it normal for the overbank to warm up when charging? Light heat (up to) 35-40°C) in the area of the connectors is normal, there is a process of voltage conversion. If the case is so hot that it is unpleasant to hold in your hand, it is a sign of malfunction. How to turn on fast charging on Xiaomi Power Bank? Nothing to turn on. Connect the device with a Type-C cable to a power supply with support QC 3.0/PD. The fast charging indicator (usually green or flashing) will light up automatically if the protocol is agreed.