USB power meter/tester thread - YZXStudio, Power-Z, RDTech and more.

There is a choice for the HD35+UM24C in the link above that I provided.

It’s a really useful tester, as it can trigger protocols like QC 3.0, and can draw up to 35W of power if the port can output it.

Awesome thanks… Got the tester and load ordered.

BTW, guess what I just found:

A QC 3.0 to VOOC/Dash Charge converter.

Meaning we can now have powerbanks with Dash Charge :wink:

Video review about the YZXStudio ZY1280 from dodge_911:

There is now also several UM25 clones which are several dollars cheaper than the RuiDeng UM25/25C that are selling for the cost of a UM24, but the AliExpress sellers don’t mention if it is the UT25 or UT25C with Bluetooth options:
DIY More UT25/25C

Also there seems to be another new company selling a unit similar to the UM25 I have never seen before selling on Banggood:

New models out: RD T66 & TC66C

I recently bought a J7-c “4-way” USB Digital Tester and I can’t seem to find anything that’ll put out more than .7 amps. Even my wall chargers listed as 2.1A won’t do it (to my iPhone 8) nor will a battery saying 2.1A output.

Do I need a special cord for my iphone to draw 2.1A?

Got the TC66C incoming for a video :)

So if I gather correctly, the ZY1280 can convert QC to PD 2.0? That’d be pretty nice. Any other device with a similar feature but a simpler to use UI? These single button devices are not my favorite.

This would allow reusing all the useless QC ports… the LVSUN LS-PD87-2C / HyperJuice 87W alone would charge both of my laptops and my phone (45W, 30W, 15W, all USB C).

See, the problem is that it’s power limited.

QC Type A chargers, which encompass almost all of the chargers on the market, are limited to 18W output, which would only be useful with some low power USB PD devices like the Pixel.

Something like QC 4.0 would work, but the protocol already includes compatibility with USB PD, so that’s not useful.

I dunno man, 京东(JD.COM)-正品低价、品质保障、配送及时、轻松购物! and both advertise 40W over USB A.

Oh that’s the second QC 3.0 Type B charger that I’ve seen.


Excuse me, what…? QC 2.0 had a Class B , QC 3.0 had no thing/ What I am missing?

There are type A and type B QC chargers.

Before USB PD was more standardized, there were different types of QC 2.0/3.0 chargers.

Type A on 2.0/3.0 was limited to 18/24W.

Type B on 2.0/3.0 limit was raised to 60/100W.

Considering how quickly usb-C PD is getting standard on laptops and phones, I don’t think USB-A would stay relevant for long for high power charging.

PD is getting things straighten up and more and more reliable chargers are coming to the market. Gone are the days where PD power supplies would maintain high voltage output even after cable reconnect which was the #1 reason for device failures. Most chargers now won’t even put out 5V unless communication with receiving device has been enabled and PD direction has been set.

I have a surface pro 6 which I use a Chinese engineered adapter to charge with a PD adapter and USB C cable. It works by “tricking” the power supply to put out 15V. It’s been working great so far.

Many phones have skipped any other type of quick charging technology and do the jump to PD directly, like iPhones. However data transfer protocols over USB-C is still a big ugly mess and would probably take a few years for most devices to standardize.

I have on the way the new zendure Supertank and Superport, both offering 100W PD 3.0. The powerbank its a bit of overkill because at highest output I would drain it completely in less than an hour. And because it was designed for these large loads, it’s not very efficient at lower power drain levels. I plan to review it when it arrives but I don’t really have the tools for a super detailed review. This is why I haven’t bothered to work on a omnicharge ultimate review either, great device btw, extremely versatile.

Well, from what I have seen phones go in every direction but USB C PD. Like, Huawei released a 10V 4A (WTF?) charger last fall — I guess 12V 3A USB C PD wasn’t good enough? There’s all that crap Oppo pulls off… And did Samsung stop their bullshit USB A QC - over USB C charger as they did with the Galaxy Book 12? That was some major standard breaking sorcery I am telling you.

Laptops, yeah, those have standardized on USB C PD very quickly.

You need a “good” cable, but most cables can do it. The thing is, 2.1A is the peak, and phones might only use it for initial charging (<50%). I think I’ve only seen the X series go above 2A. My 7+ maxes out at about 1.8A.

Most quick charge phones charge at 1.7A up to 80-90. The iPad Pro charges at more than 2 amps until 90 or so.

I’m ready to graduate from the more typical cheap, hard-to-read USB meter I have and onto something better, like an RD UM25 or UM34. Now trying to decide between the two.

I may be missing something, but on balance, I can’t discern why the UM34 would be favorable over the UM25, given the small price difference.

Am I missing something? Are there testing scenarios that escape my mind for which the UM34 is suitable but the UM25 is not?

The UM34 supports Dash Charge/VOOC protocols.