Xiaomi 20,000mAh Powerbank review & capacity test

This is the newest Xiaomi powerbank offering, the 20,000mAh model with QuickCharge. It was released about 4 months ago, but I did not order and decided to wait for a price drop. Ironically, the price went up instead and bumped from $31.99 release price to $39.99 current price. Final price from banggood was $35.00 with the use of a coupon.

-Rated capacity: 19,202/20,000mAh min/typ (68.47/72Wh)
-Rated output capacity at 5.1V/1A: 12,700mAh
-Efficiency >90% at 5.1V/1A
–6x LG cells, most likely LG 3,350mAh 18650F1 same used in the 10,000mAh version
-Output: 5V/3.6A total, 5V/2.1A max each port
-Input 5V/2A 9V/2A 12V/1,5A
-Weight: 338gr

Box & contents:
Simple cardboard box, it came with a short USB cable and user manual.I have several of that cable and they’re really nice, can easily handle 2A and any type of quickcharge.

Build quality and ports:
All-plastic construction, but it feels solid in hand. The finish is shiny and has tiny dots on the surface to improve the grip. It weight less than 2x 10,000 xiami power banks (207gr).

On the front, two USB output ports and one microUSB input. 4 LEDs indicate the remaining capacity.

A single button on the side to operate.

Specs shown in the back, most powerbanks don’t show these specs, because it could confuse regular users not familiar with the technical terms like “output capacity”.

Charge test:
Using different chargers should give you different charge rates. Testing done with a YZXstudio usb power tester, without any kind of cooling. Powerbank was empty when the test started.

Samsung 5V/2A adapter: 5.14V/1.92A for 9.8W input

Samsung fast charge 9V 1.5A adapter: 9.2V/1.72A for 15.8W input. I only tested this 3 minutes and it did not drop.

Tronsmart 3-port 48W quickcharge adapter: fresh connecting with both devices at room temp, it draws up to 12.2V 1.72A for 20.4watts. (That’s a lot of power!) but then it drops and after a couple hours it stabilized at ~1.5A for 18.5W.

I left the powerbank to charge at this rate until full, and the hottest it got was 56°C external. I pulled out the usb cable and the metal of the usb connector was even hotter at 64°C. I’m sure the internal component gets really hot, don’t know if charging at this rate could affect the lifespan of the circuit.
Charge test #1: 0-100% from a 12V quickcharge source:
Time: 6hr 45min
Input energy: 89.3Wh
Charge efficiency: 80% (72Wh/89.3Wh)

With all the heat that’s been generated, 80% charge efficiency is pretty good in my opinion. and this was utilizing the quickcharge chipset at the highest possible charge rate, if you were to charge this power bank at lower power, efficiency could be even higher due to less heat in the process, this is applies with nearly all electronic devices. Keep in mind that this is charge efficiency, how much energy required to charge the pack/actual energy of the pack.

Charge test #2: 0-100% from a 5V/2A source
Time: 9hr 50min
Input energy: 88.5Wh
Charge efficiency: 81%

Surprisingly the efficiency remained the same with a much lower charge rate.
Discharge Test:

Discharge is done by using a USB load tester, it will be set 1A and 2A. These discharge devices are great for testing the maximum possible output of a power source, they are “dumb” in the sense that it it is simply a resistor that shorts the V-/V+ of the usb to burn the power. In this case mine uses 2x 10W1RJ wirewound resistors. I added some heatsink for more effective fan cooling.

To measure everything I’m using a modified Portapow premium USB power meter. It’s been modded with a 18650 and now it can operate for a week non-stop. A regular USB tester would get way too hot and I don’t want to put my expensive meter at risk.

Discharge test #1 at 5V/2A:
Average discharge power: ~9.8W
Time: 6 hours
Output capacity: 11,837mA
Output energy: 59.3Wh
Efficiency: 83%

I expected a higher efficiency, at least 87%. Maybe the cells need a few cycles to achieve optimal capacity. Will test again with the same parameters.
Discharge test #2 at 5V/1A:
Average discharge power: 4.87W
Time: 12hr 52min
Output capacity: 12,883mAh, rated 12,700mAh
Output energy: 64.5Wh
Efficiency: 89%

This powerbank is rated 90+ efficiency at this rate, I got 89 (based on maximum typical capacity, not minimal).
To make these numbers easier to read I made this chart, note that some test are still pending:

Output coding:
Charging a Samsung S6 and an iPhone 6 at the same time did not show any problem. In the case of the samsung you see two different codings, this happens when the device being charged interferes with the identification due to the presence of signals on its own D+/D- lines. In simpler words, the device is “asking” for quickcharge but the power bank is only able to supply DCP 1.5A, this is fine as the maximum charge rate of the S6 is 1.7A with a regular 5V 2A adapter.

So far I’m happy with this power bank. It can charge all of my devices, delivers rated capacity and the build quality is high and on par with other xiaomi products. I hope my review was useful to you…

-A few more cycles to see if there’s change in capacity
-Discharge test at 5V 3A and charge test at 5V 1A
-Long term testing

Nice! I did the same test and wrote about it about a month ago on my blog.
My results :

portapow clone (the grey one) :
• In: 16,705mAh
• Out: 11,707mAh
• loading time : 11 hr 27 min @ 5.10V

yellow YZXStudio :
• In: 16,568mAh
• Out: 11,649mAh
• Loading time : 12 hr 7 min @ 5.10V

Full table with some other powerbanks to compare :

I’m working on the QC charging of it now.
Love those YZXstudio meters, got the old ones with the oled display (ZY1230 & ZY1231) almost a year now, and the QC load quite recently. Thinking about getting the green one (ZY1266) too, with built-in bluetooth for logging.

And I also own that other meter you have there :slight_smile:
Nice to see more people are getting in to this kind of testing and reviewing.

Welcome to BLF!

Good to have you here, which is your blog where you perform these tests? Those charts are loaded with tons of info, very well done.

Seems like we both got very similar results from the 2A discharge test, 11,707 vs 11,837mAh. BTW my discharge tests were done with the Portapow, I only use the YZX meter for short tests or where it doesn’t get too hot.

I already ordered the new version green ZY1266 meter from Franky, as well as the 1-3A QC USB load with fan cooling. I’m most excited for the microusb input port to measure the resistance of USB cables, normally that requieres a complicated setup. Does the bluetooth function requiere a special program to receive the data or there’s an existing app?

Thanks for the warm welcome. Stumbled across here by accident, and I ’m not regretting that :slight_smile:

My blog is (mostly) in Dutch over at http://dodgereviews.tweakblogs.net/ for now, but I’m working on something else in English, just need to get my WordPress skillz back up to par again.

There is a Chinese program from YZXStudio, or so Franky tells me.
Whether there’s going to be an English version is unknown at this point.

Also very excited for the new green meter, for exactly the same reason.
I’ve been thinking about a decent way to test cables without lots of converters to distort the results.

If you want to try your luck it’s 29.69 @ gearbest with code E2WBANK :exclamation:

Did a little test with QuickCharge on it last week…
I needed to charge SOMETHING with QC to test my new charger, right? :wink:

1st cycle on an anker 40W, 2nd on an Anker 60W, 3rd&4th cycle on an Aukey 40W 5-port that does QC, for comparison you know :wink:

Hi, please can anyone test if this powerbank can be used as UPS? Really thanks a I didn’t find any info about that.

As a UPS for what? It’s only 5V, so….
I suppose you could use the passthrough charging ability, but I don’t know how long it would survive always being connected to a charger…

Passthrough is not possible with this powerbank…

Edit: it does actually support passthrough, but not when charging in 9 or 12V

For a proper 5V UPS you can make your own with a 2x or 3x TP4054 board in the input side and a high efficiency single Li-ion to 5V on the output side, and with a pair of 26650.

Thanks for replies guys :). Shame that it does not even support passthrough charging :cry: . It looks, that just Xiaomi QC 10000mAh can be used as UPS. (btw UPS for the router 12V i got stepup 5V -> 12V)

Are you sure about that? In my review I remember testing it and it does, at 5V.
Just tested it again to make sure, and it looks like it does support it.

Nice review! :+1:


Thank you for the detailed review.
I am interested if you have tested 5V passthrough with 1A load and 2A input? I want to have uninterrupted power on the output no matter what happens with the input (on/off).

I recently bought one from their official indian webstore with the sole intention to rip the batteries out. I pried it open and I can confirm that this powerbank model cannot be opened without permanently damaging the cover. Once you open you cannot put the cover back on. It was sealed with clips, all of which face inwards and break if someone tries to open it. Guess they never wanted anyone to open it, more like a one time factory close sealing .It took some effort to take the cover off with the tip of a large knife. The cover will also get deformed due to this.

Batteries inside are definitely genuine LGABF1L11865 model. This powerbank costed only as much much as 2 of these batteries sold in retail. Wow!! 6 batteries for the price of 2.

Batteries were soldered in parallel with a thin tape shaped sheet of metal. Took that off with some force. Charging board also had a thermistor to monitor battery temperature. I’m gonna salvage that component.