Xiaomi Mi Power Bank 3 20000 mAh has become one of the most popular external batteries thanks to a combination of capacity, compactness and price. But many users face the confusion: how long does it take to fully charge the device? The answer is not so unequivocal – time depends on the power of the charger, the type of cable and even the ambient temperature.
In this article, we’ll break down all the nuances, from standard charging times (3-12 hours) to ways to speed things up without harming the battery. 18W charge the superbank in 5-6 hours, and cheap "nouneim" on 5W — We'll also uncover the myths of "first charge" and explain how to properly store the device so that it lasts 5 hours.+ years.
1. Xiaomi’s standard charging time of 20,000 mAh: table by adapters
The Xiaomi Mi Power Bank 3 battery capacity is 20,000 mAh (74 Wh), but the actual available capacity is about 12,000-13,000 mAh due to voltage conversion losses. Charging time is directly dependent on the power of the power adapter. Below is the table for the original USB-C → USB-C cable (or USB-A → USB-C with Quick Charge support).
| Adapter power | Type of charging | Full charge time. | Notes |
|---|---|---|---|
| 5W (standard USB) | Normal. | 10-12 hours | Minimum speed, not recommended |
| 10W | Normal. | 6-7 hours | Average speed for budget adapters |
| 18W (Xiaomi original) | Quick Charge 3.0 | 4.5-5.5 hours | The best option for speed/safety balance |
| 30W+ (PD-charging) | Power Delivery | 3-4 hours | Maximum speed, requires a USB-C cable → USB-C |
| 65W+ | Super Charge | 2.5–3.5 hours | Possible overheating with prolonged use |
⚠️ Note: If your overbank charges for more than 12 hours with an adapter 18W+, Check the cable, it's probably not fast charging or damaged. Use only certified cables. USB-IF marked 5A.
Use Power Delivery (PD) or Quick Charge (QC) adapters to speed things up. For example, the Xiaomi GaN Charger 33W reduces charging time to 3.5 hours and the Baseus 65W to 2.5 hours. However, the constant use of heavy-duty adapters (65W+) can reduce battery life by 10-15% due to increased heat generation.
2.Why does the overbank charge longer than the stated time?
Even with an 18W adapter, your Xiaomi 20000 mAh can charge for 7-8 hours instead of 5.
- 🔌 Low quality cables: Cheap cables have thin veins that limit current to 1–1.5A 2–3A.
- 🌡️ Overheating: at temperatures above 30°C controller of the overbank automatically reduces the charging current.
- 🔋 Battery wear: After 300-500 cycles, capacity drops by 20-30%, and charging time increases.
- 📱 Parallel use: if the overbank charges the phone at the same time, its own charging slows down 1.5-2 times.
To check the actual charging speed, use apps like AccuBattery (Android) or CoconutBattery (iOS/macOS). Connect the Verbank to the phone via OTG-adapter - the program will show the current current (in mA) and voltage.
How to check the power of the adapter without applications?
⚠️ Warning: If the verbank heats up above 40°C while charging, immediately disconnect it from the mains.°C can cause the battery to bloat. Normally, the temperature should not exceed 35.°C.
3. Optimal charging algorithm: how to extend the service life
Xiaomi’s lithium polymer batteries are designed for 500-800 charge-discharge cycles, and to maximize this period, follow the rules:
- Avoid full discharge. Start charging at 20 to 30 percent of the remaining amount. Deep discharge (below 5 percent) reduces battery life by 2-3 times.
- Don't hold it 100 percent long. Once you reach 100 percent, disconnect the power bank from the grid -- maintaining maximum charge all the time accelerates degradation.
- Use a "sparing" mode. Charge to 18W, not 65W, which reduces heat generation.
- Store at 40-60% of the charge. If you do not use the superbank for more than a month, discharge it to 50% and store it in a cool place (10-20 ° C).
For models Xiaomi Mi Power Bank 3 Pro (with display) is available Low Current Mode – it reduces the charging current for delicate devices (earphones, fitness bracelets). Activated by double press of a button.
Use the original Xiaomi cable|Check the adapter voltage (not lower) 5V/2A)|Charge at room temperature (20–25°C)|Do not connect the load (phone) during the first charge|Wait for the full cycle (0% → 100%)-->
4. Myths about the first charge: what is true and what is not
There are a lot of tips on the Internet for the "correct first charge" of the superbanks, let's take a look at the most common ones:
- ❌ "You have to completely discharge and charge 3 times. Lie. This is true for nickel metal hydride (Ni-MH) batteries of the 2000s".
- ✅ "The first charge must be full (0% → 100%)" True, but with nuances. It's for calibrating the controller, but not for "swinging" the battery.
- ❌ "Charge strictly 12 hours. Lie. Time depends on the adapter (see table above.
- ✅ "You can't interrupt the first charge. Really. Interrupting can knock the calibration of the charge indicator.
The only rule for the first charge is: use the original adapter (or certified analogue) and wait for the full cycle.
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If the charge indicator is 100%, but the overbank discharges quickly, calibrate: completely discharge it (before turning it off), then charge it to 100% without interruption. Repeat 1-2 times.
5.How to speed up charging without harming the battery
If you need to charge the overbank urgently, use these methods (battery safe):
- Use it. PD-charging 30W. Power Delivery adapters (e.g. Xiaomi) 33W Anker 30W) Reduce time by 30-40% compared to standard 18W.
- Charge at 20–25°C. At low temperatures (below 10°C), the current automatically decreases. In heat (above 30°C), the risk of overheating.
- Turn off the load. If the overbank charges the phone at the same time, its own charging slows down 1.5 to 2 times.
- Use a short cable. Cables longer than 1 meter lose up to 20% of power. The optimal length is 30-50 cm.
⚠️ Note: Do not use "turbo modes" (e.g. Xiaomi HyperCharge) 120W) They're designed for smartphones with cooling systems, overheating the battery of over 45.°C can lead to irreversible damage to cells and risk of fire.
| Acceleration method | Saving time | Risk to the battery |
|---|---|---|
| PD-charging 30W | 30–40% | Low. |
| Charging at 20°C | 10–15% | Absent. |
| Short cable (30 cm) | 5–10% | Absent. |
| Charging without loading | 50% | Absent. |
| Adapter 65W+ | 60% | High (overheating) |
6 Storage and transportation: how not to spoil the overbank
Improper storage is one of the main reasons Xiaomi’s superbanks fail prematurely.
- 📦 Storage charge: 40-60% Fully discharged or 100% charged battery loses capacity 2-3 times faster.
- 🌡️ Temperature: from 10°C to 25°C. Cold (below 0)°C) the battery may temporarily lose up to 30% of capacity.
- ☀️ Avoid direct sunlight. Ultraviolet accelerates the degradation of lithium-polymer cells.
- ✈️ Aircraft: Verbanks up to 100 Wh (27,000 mAh) are allowed in hand luggage. Xiaomi 20000 mAh (74 Wh) is standard IATA.
If you don’t plan to use the powerbank for longer than 3 months, do a quarterly “preventive” charge-discharge (0% → 100% → 40%) to prevent deep discharge and prolong life.
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Optimal storage conditions: 50% charge, 15-20°C temperature, dry space, under these conditions, the battery loses no more than 5% capacity per year.
7. Frequent problems and their solutions
If your Xiaomi 20000 mAh is acting strangely, check out these points:
| Problem. | Possible cause | Decision |
|---|---|---|
| Not charging at all. | Cable/adapter damaged | Try another 18W+ cable and adapter |
| Charging too long (>12 h) | Weak adapter or battery wear | Use it. PD-charging 30W. If it doesn’t work, replace the battery. |
| It's discharged fast. | Calibration of the indicator has failed | Perform 2-3 full charge-discharge cycles |
| Heated above 40°C | Failure of the controller or cells | Stop using, contact the service |
| Not included after storage | Deep discharge. | Try to "resuscitate" with a current limiter (3.7V, 0.5A) |
If the superbank stopped holding the charge after 1-2 years of use, the lithium polymer cells are likely to be worn out. ~1500–2500 ₽), It is often cheaper to buy a new one.