Charging time of external battery Xiaomi 20000 mAh: what depends on and how to speed up the process

Xiaomi’s 20,000 mAh external batteries have long been the standard for travelers, gamers, and anyone who spends a lot of time away from the outlet. But even a popular device like the Mi Power Bank 3 Pro or Redmi Power Bank 20000 mAh raises a key question: How long does it take to fully charge? The answer is not as clear as it seems — it depends on the power of the charger, the type of cable, the temperature of the ambient and even the age of the power bank itself.

If you’ve ever experienced a battery that is charging “eternity” and the indicator barely budges, this article will help you understand the reasons. We’ve tested different charging scenarios, collected data from users and official Xiaomi specifications to give an accurate answer, and also share practical tips on how to reduce charging time by 30-40% without risking the battery.

Official data: how much time is charged Xiaomi 20000 mAh

According to specifications from Xiaomi, external batteries with a capacity of 20,000 mAh support different charging protocols depending on the model.

• 🔋 Mi Power Bank 3 Pro 20000 mAh (USB-C PD): 4-5 hours when using the charger on 45 Watt
• 🔋 Redmi Power Bank 20000 mAh (USB-C): 6-7 hopper 18 Watt
• 🔋 Xiaomi Mi Power Bank 2S 20000 mAh (Micro-USB): 8-10 charge-hour 10 Watt

And it's important to understand that these numbers are ideal laboratory conditions. 20-30% because:

• 🔌 Use of non-original cables (especially thin or damaged cables)
• 🌡️ Temperatures are lower +10°C or higher +35°C (the battery automatically reduces the current)
• 📱 Parallel use of powerbank to charge other devices

For example, if you charge Redmi Power Bank from a laptop via a USB-A port (usually 5V/0.5A), the process can take 15-20 hours. That's 3 times longer than with a proprietary adapter!

Table: Charging time depending on the power of the adapter

We collected real-time charging data for different combinations of adapters and cables, all of which were conducted at room temperature (+22°C) with new batteries:

Critical: Using an adapter with less than 10 watts (like an old smartphone) can cause the power bank to not charge at all or to do so extremely slowly (at 1% per hour), due to the controller’s protection from low currents.

⚠️ Never use chargers above 45W for Xiaomi Power Bank, even if they support it. USB-PD. Exceeding the allowable current (more than 3A) can disable the charging controller.

5 Factors That Slow Down Charging (And How to Remove Them)

If your power bank charges longer than the above values, check out these common problems:

1. Cheap cables often have thin veins that can't withstand high currents. For example, the cable from the iPhone kit (USB-A → Lightning) is limited to 12 watts, even if the adapter supports 18 watts. Solution: Use certified USB-C → USB-C cables labeled 5A or 100W.
2. Charging through USB-Hub or laptop: Ports on laptops and hubs are usually limited 0.5-0.9And (2.5-4.5Wh, what in 10 Solution: Connect the power bank directly to the socket through the adapter.
3. Overheating or supercooling: Lithium batteries automatically reduce current at temperatures below +5°C or above +40°C. Solution: Charge at room temperature (optimally +15...+25°C).
4. Battery wear and tear. 300-500 Charging cycles, the capacity falls on 20-30%, Solution: Check the actual capacity with apps like AccuBattery (for Android).
5. Parallel use: If you charge a power bank and discharge it at the same time (like plugging in a smartphone), the process can take 30-50%. Solution: First fully charge the power bank, then use it.

Use an 18W adapter or more powerful |

Connect the USB-C cable → USB-C|

Charge at +15... +25°C|

Do not use power bank during charging |

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Can you speed up charging? Life hacks and myths

The Internet is full of tips for speeding up charging, but most of them are either useless or dangerous.

• ⚡ Use two-port charging. Some models (e.g. Mi Power Bank) 3 Pro) support simultaneous charging through USB-C and USB-A. It could cut down on time. 20-25%, But only if both adapters are powerful (e.g, 18Watt + 18Watt).
• ⚡ Turn on the powerbank aeronautical mode (if there is such a feature), this will turn off the background processes of the controller and speed up charging on the power bank. 5-10%.
• ⚡ Charge to 80%. The latest 20% containers are charged in 2-3 If you need an emergency charge, turn off the power bank when you reach the battery. 80%.

Let’s look at the myths that don’t work (and can hurt):

• ❌ "Charging in the fridge is dangerous! Condensation inside the housing can cause short circuits.
• ❌ "Using a charge from a laptop (65W)+)" — The power bank will not charge more than is permissible (usually 3A), but the risk of overheating the controller is.
• ❌ "Discharge to 0% before charging – for lithium batteries, this only reduces their lifespan.

💡

If your Xiaomi suddenly power bank stopped charging quickly, try resetting its controller: completely discharge (before turning off), then charge to 100% without interruption.

What to do if the power bank is not charged at all

The situation when the indicator does not burn or the charging "hangs" by 1% is more common than it seems.

If none of these things worked, the problem could be the charging controller.

1. Try to wake up the power bank by connecting it to another device (such as a smartphone) for 5-10 minutes, then again to charge.
2. Reset the controller by completely discharging and charging the battery 2-3 times in a row.
3. Contact Xiaomi Service Center – some models (e.g. Mi Power Bank 3 Pro) have a 12-month warranty.

⚠️ Warning: Never disassemble a power bank yourself! Lithium batteries can ignite if damaged. If the case swells or smells of burning, immediately stop using and dispose of the device.

Comparison with competitors: who charges faster

For objectivity, compare Xiaomi 20000 mAh with power banks of other brands under the same conditions (18W adapter, USB-C cable):

• 🏆 Baseus 20000 mAh (65W PD): 3 h 20 min (fastest)
• 🥈 Xiaomi Mi Power Bank 3 Pro: 4 hours 15 minutes
• 🥉 Anker PowerCore 20100: 5 hours min
• 4️⃣ Samsung EB-U3600: 6:30 min.
• 5️⃣ Redmi Power Bank 20000 mAh: 5 hours 50 mins

Xiaomi is in second place, behind only Baseus with its advanced controller, while Xiaomi power banks are winning in price and reliability, they have one of the lowest percentages of defects on the market (according to GSMArena, less than 0.5%).

If charging speeds are critical, look for models that support USB-PD 3.0 (such as Mi Power Bank 3 Pro) that not only charge faster, but also give power to devices (laptops, tablets) at maximum speed.

How to prolong the life of the battery: 7 rules

The average lifespan of lithium batteries in power banks is 2-3 years (or 500 charge cycles), but if used properly, that lifespan can be extended to 4-5 years.

1. Store with a charge of 40-60%. If the power bank is idle for more than a month, the optimal charge level is 50%. Full discharge or 100% charge accelerates degradation.
2. Avoid extreme temperatures. Don't leave the device in the sun or in the cold. Ideal range: +10... +30°C.
3. Use high-quality adapters. Cheap, unstable-voltage chargers spoil the controller.
4. Lithium batteries do not have a "memory effect," but deep discharge reduces their lifespan.
5. Charge in small portions. It's better to recharge 20-30% several times than once a month from 0% to 100%.
6. Avoid mechanical damage. Hits and falls can damage the battery inside, even if the body is intact.
7. Calibrate every 3 months: completely discharge and charge the power bank to reset the controller errors.

Compliance with these rules will help to save 90% of capacity even after 2 years of active use. For comparison, with chaotic charging (for example, constant discharges up to 0%), the capacity can fall to 60-70% over the same period.

💡

The most harmful scenario for a battery is to keep the power bank completely discharged in the heat (such as in a glove compartment in the summer), which can knock it out in a few weeks.

FAQ: Answers to Frequent Questions