Xiaomi Mi 2 Powerbank 20,000mAh Review - New 20Ah King?

so basically the PLM05ZM is THE BEST power bank of the world at the momentā€¦!
of course among the 20k power banksā€¦. going OVER is just stupid and corrupts portability

I received a new USB load and meter today and was able to do some output stress testing.

5V: No problem up to 2.4A, output voltage gets a significant bump above 1.5A.

9V: No problem up to 2.4A.

12V: Fine up to 2.2A, which is 26W of power. No phone is every going to draw that much power from a USB-A.

Hi, can you introduce the USB load and meter?

AVHzY CT-2 / KT001 meter and YZXstudio ZL1100 load. Testing the offline curve recording functions right now. I had the ZY1276 but the AVHzY is superior in every way.

Thanks, will34.

Maybe you could do a quick-look mini-review of this USB meter in a separate thread? Looks interesting. Just did a Google search, it looks like the CT-2 is also marketed as the KT001 (Power-Z) and the Kotomi Premium (Kotomi ā€œPreā€).

Many new USB meters with more powerful features have just arrived the past year, though one important functionality is interfacing with a PC software and to be able to record/graph/chart data values (which the ZY1276 unfortunately does not ā€” it only outputs raw values, but no in-house PC software that can do graphs other than read values).

Of course, one other thing is whether the USB meter is as accurate as it says (4 decimal places is already very accurate, in my opinion). Unfortunately, would need specialized equipment (like HKJ) to verify that theyā€™re really preciseā€¦ Iā€™d like to think that the ZY1276 is factory-calibrated to be accurate (canā€™t be sure if it really is thoughā€¦)

Another thing is to allow the USB meter to be powered independently (so it doesnā€™t drain a minimal current from the USB power device it is testing, which affects the result) ā€” ZY1276 doesnā€™t have this, but it looks like the KT001 can have independent power source so as not to affect results of the device being measured.

I especially liked the efficiency ratings :slight_smile:

Recharge time 6hr 11min @ 12V/1.6A max (with QC)
I donā€™t have a QC charger, but I do have a charger that can deliver 3.5A over a standard USB micro cable.
So my question is: Can the PB charge fast without QC but high amp ā€˜regularā€™ charge at 5v?

I made a video about this powerbank, where I also test charging with 5V nonQC.
Seems to top out at about 2A.

[quote=will34]

What are the advantages of the AVHzY CT-2 / KT001 over the ZY1276 ?

[quote=angerdan]

Better interface, easier navigation with 3 button, QC trigger, MFi authentification, USB PD support, PD listener, more user friendly Desktop app, internal memory for 5 graphsā€¦ and the list goes on :smiley:

Thatā€™s a shame because that means a very long charging time for such a beast.
I have 26800 EasyAcc with 2x2.1A. I wouldnā€™t want to go back to even slower charging.
Often it doesnā€™t matter it takes many hours to charge, but sometimes, like between flights, itā€™s ā€˜essentialā€™ to charge as quickly as possible.
Where ae the powerbanks that charge 60% in 15 mins like modern phones?

In the future, USB-C with PD will be integrated in planes. So in a few years thereā€™s no need for charging between flights. By the way, how about chargers in trains in the countries youā€™re traveling?
https://www.ifpl.com/ifpl-deliver-fully-integrated-usb-in-seat-power-solution/
https://www.ifpl.com/wp-content/uploads/2018/02/IFPL-2018-02-AIX-Period-1-Media-Release.pdf
https://apex.aero/2017/09/29/ifpl-solutions-airlines-c-future

Your EasyAcc 26800 contains 99Wh, so to charge it from 0-60% in 15m, 240W would be needed.
I doubt that a reliable phone will pump up from 0-60% in 15m without increasing degradation of the battery.
Modern smartphone batteries ale LiPo batteries and degrade faster. Also the have only 1-1.5Ah, so with 2C 50% in 15m are possible.

With 18650 cells 1.5A-3A are regular. Only few cells can be charged with up to 6A, like the Sony Konion US18650VTC6.
An 4x18650 powerbank charging each cell at 3A you already have 44W of energy consumption. No USB power plug offers 9A at 5V to charge a powerbank with this current.

Even powerbanks with 12V/2A input can be charged with not more than 40W.
https://www.amazon.co.uk/Poweradd-Pilot-Pro2-Multi-Voltage-Notebooks/dp/B013HXKZYW
https://www.amazon.co.uk/Laptops-50000mAh-Portable-External-Notebook-Most/dp/B07CZDX2ZG
https://www.amazon.co.uk/MAXOAK-Capacity-50000mAh-Portable-Notebook-Most/dp/B00YP823NA
https://www.amazon.co.uk/LitioniteĀ®-Tanker-Aluminium-connectors-Smartphone-Black/dp/B01LZXPMXM

I just take my 12A charger with me :slight_smile:
6x3.5A + 3x2.5A + 3x1.5A all a 5v. Simultaniously. Not even expensive. I love that thing :slight_smile:

OnePlusā€™ Dash Charge pushes 4A @5v. (20Watt)

I think itā€™s no problem to build a 9A charger but the cables would get overly kinda thickā€¦
But 3x 3A should be possible.

Anyway, charging at the max. theoretical speed is possible isnā€™t even my main point. There is a lot between 2A and 9A (or more as my PB fits 8 cells)

My fav charger

Sorry if this has been asked before, but has anybody observed unusually slow charging with this model? Mine has started to charge at 0.92A throughout the entire charge cycle and iā€™ve confirmed that itā€™s neither a charger nor cable problem, my 5000mAh Xiaomi charges consistently at 2A, while this 20000mAh always did 1.42A max.

Not really, experience with my PLM05ZM.

Since I have a USB meter (actually I have several) I notice it usually registers 5.01v without any load (just USB meter), but when loaded a bit, the voltage can dip to say 4.94v, but at other times, just replugging the same device (smartphone), the voltage will instead go up with load.

My smartphone charges at max 1.74A (tested with several USB meters and using different power outlet chargers/powerbanks). But when display is ON, the max charge rate is 1.15A, again only when the smartphone is less than about 75% full (if more than 75% full, the charge rate will not reach 1.74A but will be lower).

Anyway, what Iā€™m mentioning is that sometimes replugging the smartphone on the PLM05ZM, the voltage is up to 5.15v, then the charge rate can reach 1.74A. But when the voltage is around 4.94v, the charge rate is just up to 1.3-1.4A. Iā€™m not very sure how to trigger the powerbank to have voltage go slightly up or down thoughā€¦

The smartphoneā€™s charge current DOES appear to correlate with the voltage itā€™s sensing (which can also be affected by the cable used ā€” using a worse quality cable will have lower charge current)

" voltage gets bumped from 5.0V to 5.2V. "

https://imgur.com/a/Z1sdYDN

This is why I see these spikes in the graph (USB24C USB meter)?

I am charging with an Orico charger, which has max 2.4A/port, but it is only charging with ca. 2A. It is normal?

1. Yes this is normal. This is done because of the resistance of the cable, so the charger bumps the voltage to 5,2V so the phone/powerbank receives 5,0V.

2. It has 2,4A max output, but the device decides what current it is charging at. In this case, it is 2A. So, perfectly normal.

Cool, thanks for the answer. :slight_smile:

This powerbank will ā€œboostā€ the output voltage when the current exceeds 1.5A, it is programmed to always do it because it has no way to detect cable resistance (for that you need feedback on the other end of the cable). but in your case the spikes are due to drops in the current draw.

Some manufacturers claim their powerbank being smart and will detect voltage drop across the cable/connectors and compensate for that, but theyā€™re just being programmed to ramp up the voltage according to the current.

The Micro USB has an maximum rated current of 2.1A, and the 2.4A rating was designed for Apple which implemented 12W charging for their iPads. So even if your charger has a higher amp rating, no device with Micro-USB input should exceed 2.1A on the input side (in theory)

Thanks for that explanation, I have also been wondering how ā€œpowerbanksā€ can really detect voltage drop since the drop is on the other endā€¦

I do notice several such behaviors, USB voltage increases a bit when current increases, different chargers/powerbanks implement them slightly in diffferent ways at different voltage thresholds (I use EBD-USB+ to do a current load sweep and notice the voltage changes).

For smartphones (mostly Iā€™ve only checked a few older Samsung phones, and they typically charge to 1.8A max current at USB 5v. Itā€™s only some powerbanks that Iā€™ve noticed charging at 2.0A or sometimes spiking over 2.0A charging current)ā€¦

The Xiaomi powerbank in particular, seems to continuously ā€œtestā€ the charge current and voltage every now and then, at least thatā€™s my understanding of the ā€œspikes/dipsā€ when I try to graph the Mi powerbank when it is getting chargedā€¦

Looks like Banggood pulled the olā€™ switcharoo. The link in the OP takes you to the old version. 3.7v (74wh) instead of the 3.85 (77wh). Didnā€™t notice it till I got mine today. Not a major deal for me but you all should be aware if you are looking for the one in the review.