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

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 https://www.hypershop.com/products/hyperjuice-87w-dual-usb-c-charger-with-qc-3-0-usb-a both advertise 40W over USB A.

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

Nice.

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.

According to RD’s own comparison table, they both do, and the UM25 supports Huawei’s fast charge protocols in addition.

That would be a minor consideration anyway, since I don’t envision a device that utilizes yet another proprietary fast charging standard in my future. I’m fine with USB PD and hope that’s where it will be centered. QC has enough critical mass to continue, and QC4 will have PD compatibility, which will help.

On paper, the 25 is superior in almost every regard, except that it has a USB 2 and not USB 3 port, but I’m not sure how relevant that is when these meters are only taking power measurements.

That’s why I’m puzzled.

By my testing, only the UM34 supports Dash Charge/VOOC charging via a USB-A port.

Thanks. Those are the kind of nuances I seek.

The sales material associated with the early reviews of the UM25 did not indicate that support like the current table does, so I guess it was added to the UM25 in an update at some point.

Do you have the C version? I figure it’s better to have it, than regret not getting it, but the mention of ads in the smartphone app would be a bummer.

Yes, I do have the UM25C, UM34C, and recently acquired the TC66C.

Only the UM34C supports Dash Charge due to the additional pins of the USB 3 connector on that meter.

No ads in the smartphone version.

I’ve already received the RD TC66C, however when I connect it between the charger’s cable and the smartphone, it doesn’t charge:

If I connect the YZXStudio between the wall charger and the cable it charges to 1.7 amps aprox. Where could the problem be?

Does anybody know how to contact RD’s tech support? On AliExpress’s page there isn’t any email available.

RD TC66/TC66C Type-C PD trigger USB-C Voltmeter ammeter voltage 2 way current meter multimeter PD charger battery USB Tester

It seems like the data lines are not receiving any signal. It shows 0V - & + and default 1.5A DCP. The YZX meter detects the load and is forcing the charger to put out a different charging protocol and it starts to charge. There is voltage reading at the end of the cable so I guess the issue is at the phone’s side.

It could be many reasons this happens and without knowing which phone, charger and cable you’re using there’s no way to troubleshoot. Have you tried to manually trigger PD or QC 5V? In theory that should work.