Which is the best 20000 mAh power bank?

Xiaomi is known among the masses not only for inexpensive smartphones, but also for various accessories for them, including power banks. We tested the most popular model – Xiaomi Mi power bank 2 20000mAh. Today we will figure it out, is 20000 mAh power bank good or not.

Appearance and dimensions of Xiaomi 20 000 mAh power bank

Xiaomi Mi power bank 2 with a capacity of 20,000 mAh looks almost unchanged in comparison with the first generation: a glossy plastic surface with protruding “points” that prevent slipping, the ends contain service information on one side and two USB connectors with microUSB on the other. The edges are substantially rounded, making it comfortable to hold with one hand, but the same is true for its predecessor.

The difference lies in the actual size: the new product has become narrower and slightly lower (135.5 × 67.6 mm versus the old 141.9 × 73 mm), but has grown fatter to 23.9 mm from 21.8 mm. You cannot put a new can under a smartphone, but the weight (331 g) predetermines that using an external battery in this way is inconvenient, it must be carried in a bag or backpack, and from there the cable must be pulled.

Information about the charge level is reported by four diodes, which is effective in batteries with 5000mAh or 10,000mAh, but not enough for a twenty-thousand model. If there is no discomfort at a high charge level, then the last active diode is confusing, since it burns with the remaining 2500 mAh and 100 mAh. Here the manufacturer should take an example from TP-Link TL-PB15600.

How much is 20000 mAh power bank capacious?

The first and second generation Xiaomi Mi power bank 2 20000mAh are the two most popular power banks.

The first place says that Internet users are interested in high-capacity batteries, and the Xiaomi brand attracts buyers. The last passage in the case of power banks is logical due to good quality and pleasant prices, but not everyone needs an impressive capacity.

The power bank must solve one problem – to provide enough power for the devices to operate during the period “from outlet to outlet.” If we talk about daily use, then this is the time from wake up to lights out, lasting from 18 to 22 hours on average, depending on the specific situation, that is, Xiaomi Mi power bank 2 20000mAh is needed only for those who use one or two smartphones and a tablet.

The rest should look at less capacious, but lighter and more compact models that fit in a pocket and in size will allow you to hold both a power bank and a smartphone in one hand. A long cable is necessary for a capacious representative of the Xiaomi family (a short one is included in the kit), but in urban mode the cord will interfere and cling to turnstiles, door handles and other protruding blocks of the urban environment.

So how much is 20000 mAh power bank capacious? In general, we can say that it is excessively capacious for an urban environment. For most users, the capacity of the Xiaomi Mi power bank 2 20000mAh will be excessive for constant use, but it will be necessary for hiking, camping, travel and flights, especially with transfers and overnight stays in transport.

A family of three can charge smartphones once and add energy to the tablet, on which the child watches cartoons, and mom and dad watch TV shows. At the same time, a long cable will not interfere, since the power bank will be used stationary, and not on the go.

Tests of Xiaomi 20 000 mAh power bank

Xiaomi Mi power bank 2 20000mAh at a voltage of 5.1 V provides a capacity of 14,000 mAh (which is honestly written on the end of the device). This is 1300 mAh more than the first generation:

In addition, the new power bank, in addition to its size and capacity, has redesigned energy output modes: 5.1V / 2.4A, 9V / 2A, 12V / 1.5A are available, which covers most of the basic fast charging variations from many manufacturers. Almost any device with support for accelerated power recovery will charge from Xiaomi Mi power bank 2 20000mAh quickly, albeit slower than from a specialized charger.

Xiaomi Mi power bank 2 20000mAh lasted 4 full charges of iPhone 7 Plus (2900 mAh) and one more charge from 2% to 9%, in the second test the device charged iPad Air 2 (7340 mAh) from 2% to 100% and again from 3% to 83%. The charging speed of the iPad matches the charging from the included power supply, the iPhone charges in 1 hour 50 minutes, the Nexus 6 recognizes the smart Quick Charge 2.0 fast charging mode.

The battery is fully charged in 8 hours from the unit with support for Quick Charge 2.0, while Xiaomi practically does not heat up. The device operates in the «passstra» mode (charging from an outlet and simultaneously supplying power to connected devices), the output can be 3.6 A in total from two USB connectors, but even with such loads, the case remains a little warm.

Two simultaneous connections are not an advantage, but a necessity for such capacious power banks

The manufacturer claims that it has implemented temperature protection, protection against short circuit, overload of the output current and overvoltage (including the output), misuse of connectors, and prevents the device from overcharging or unnecessarily discharging. A standard set for power banks is present.

Thus, answering the question, is 20000 mAh power bank good or not, we can confidently say that it is definitely yes.

Is 20000 mAh power bank allowed in flight?

Almost all modern airlines are allowed on board with Li-Pol or Li-ion batteries with a capacity of up to 100 W·h or up to 160 W·h with a Lithium content of no more than 2 g. For example, in the new MacBook Pro 16, the battery has just been adjusted to a value of 100 W·h so people can fly safely. However, it is important to remember that such batteries cannot be checked in luggage, but must be taken with you to the salon. For example, if you are carrying a gyro scooter in your luggage, then you need to remove the battery from it, isolate the contacts and take it with you in your carry-on luggage. The same applies to additional batteries for a camera or medical equipment. In general, batteries cannot be transported separately in checked baggage. In addition, do not be surprised if your external battery disappears from your suitcase upon arrival.

Now let us find out how much 20,000 mAh is in normal Wh. Usually, on good batteries, the capacity value is also written in Wh, however, if you do not have such an inscription, then it is not difficult to calculate the capacity in Wh. It is important to know one thing, almost all modern power banks are equipped with Li-Pol or LiFePO4 (lithium-ferrum-phosphate) batteries. They, in turn, have a rated output voltage of 3.7V. Now, to calculate it is enough to convert mA · h (milliampere-hours) to Ah (ampere-hours), simply dividing the value by 1000. Then multiply the indicator by the nominal voltage.

20,000 / 1,000 = 20 A·h

Next, you need to multiply A·h by the rated voltage of 3.7V.

20 A·h х 3.7V = 74 W·h

That is, an external battery for 20,000 mAh will have a capacity of 74 W·h. However, even if we imagine that the nominal voltage of the batteries in your power bank is 5V, its capacity will be exactly the same 100 Wh. Recall that most airlines’ requirements are limited precisely at this level, which means that this value does not exceed safety standards.

Therefore, the answer to the question, is 20000 mAh power bank allowed in flight – yes, you can. The truth is, you should take into account the rules of different airlines, they may differ slightly and you should take into account their requirements. For example, Aeroflot allows batteries up to 100 Wh in carry-on baggage. It is also worth considering the number of gadgets that you take with you. However, we often fly to exhibitions with backpacks packed with equipment and have no problems. Therefore, you probably will not have them either.


Xiaomi Mi power bank 2 20000mAh is not suitable for everyday use in the city due to its mass and size, but if less capacious options cannot cope with the loads, you will have to come to terms with these shortcomings.

Powerbank offers a minimalistic design, copes well with high loads (does not heat up) and takes into account the mandatory requirements in the form of two connectors for energy output and the «passstra» function, and several power modes solve the problem of charging different devices. The only serious drawback is the uninformative indicator of the level of the remaining charge.

The plastic case does not require buying a cover to protect other devices from scratches, and the cost allows you to buy a gadget in a pair to a more compact city power bank without waking up the «toad». At the same time, it does not give away cheapness, but is perceived, as it should – a utilitarian and convenient accessory. Thus, on long trips and flights, where dimensions are the last thing, Xiaomi Mi power bank 2 is exactly the battery, which is the best 20000 mAh power bank.

Finally, we note 5 main reasons to buy exactly Xiaomi Mi power bank 2 20000mAh:

  • minimalistic design;
  • high-quality assembly;
  • reliability and durability
  • excellent work under high loads;
  • allowed to take on the plane in most airlines