[Review] RD UM34C Usb Meter With Bluetooth Connectivity - 26/07 Updated with Voltage/Current Graphs

bilakos10 · 2018-07-09T19:25:06.000Z

The UM34C was sent to me by RD Official Store in AliExpress for review.
Here's the product's page: RD UM34C

The USB meter comes in a simple tin box with a plastic display window.

The meter is seated inside a laset cut foam mold to protect it during shipping.

The device itself is using a quite big 1.44 inch color display with quite a sharp, for the application, resolution.
I found the viewing angle to be surprissingly good.

The back side of the meter has just a plastic piece to protect the pcb's components from an accidental short.

The upper side of the device utilizes a regular microUSB port along with two buttons used for controling the displayed information and a Bluetooth switch.
The manufacturer recommends that the maximum current through the port shouldn't exceed 2A, but my tests showed that the port can withstand higher currents than the ones stated.

Following the previous pattern, the lower side of the device implements a type-c port alongside with two more buttons.
The max recommended current through the port is 4A.

Powering on the device, introduces the user to the basic info screen.
(The 5 available info screens can be scrolled through using the lower two buttons)
The basic info panel displays the following info:
Voltage (V)
Current (A)
Power (W)
Capacity(mAh)
Energy (mWh)
Resistance (Ω)
Internal temperature of the meter (C)

The second screen except from the basic readings, introduces the voltage measurements of the data lines along with the current charging mode.

The third panel is used for displaying the basic stats of a charge cycle along with with a recording indicator and the nominal amperage after which the data recording starts (0.10A in our case).
The recorded data can then be extracted in Excel format through the dedicated Android application.

The fourth screen is a quite interesting one as it's used for measuring the resistance of a cable.
In order to get a measurment, an adjustable electronic load is needed in order for the meter to record the voltage drop across the cable and thus its resistance.

The follow up panel shows a graph of Voltage against Current over time.
It allows for a graphical representation of a power supply's performance under different loads.

The final screen allows the user to adjust some parameters in the way that the data is represented as well as set the screen's timeout.

Using the provided Android application, the user can have live access to the live data as well as control the device.
As seen, the applications gains access to every piece of information that the meter can display and also allows the user to tweak some of the available parameters.
Also, all of the saved data can be easily pulled into an .xls document.

To sum everything up, I was pleasantly surprissed to finally see a budget USB meter that can provide such a wide range of information.
I double verified the all the recorded data with two other of my usb meters and every reading seemed to be on point.

Update

Here's a few Voltage / Current graphs I created using the UM34C combined with the LD25 electronic load.

Here's a quick clip to show you how to use the cable's resistance measurement mode of the meter.
www.youtube.com/embed/mY5AZ2KPL40

angerdan · 2018-07-15T12:13:51.000Z

Thanks for the review!

bilakos10 · 2018-07-15T19:08:09.000Z

angerdan:

Thanks for the review!

You are welcome mate

angerdan · 2018-07-15T19:54:18.000Z

I’m curious about an YZXStudio ZY1280 vs. RD UM34C shootout
Only the ZY1280 seems a bit expensive with ~$60.

Review request for HKJ [USB Power Devices] USB Power Devices

YZXStudio ZY1280 [image] http://www.kaayee.com/product/yzxstudio-zy1280-usb-meter-qc4-pd3-0-mfi-pps/ https://www.fasttech.com/product/9654021-yzxstudio-zy1280-usb-power-meter-power-delivery https://www.ebay.com/itm/ZY1280-USB-Power-Monitor-Current-Voltage-Capacity-Quick-Charge-QC4-PD3-0-MFI-PPS/173408572140 https://aliexpress.com/item/YZXstudio-Farbe-Meter-USB-Strom-Spannung-Kapazit-t-Schnellladung-QC4-PD3-0-MFI-PPS-Protokoll-Tester/32851111369.html . . QooPow™ qualMeter (Basic) [image] …

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

The new ZY1280 appears to be the upgrade from the ZY1276 / ZY1276P(Plus?). The ZY1278 appears to just be the USB-C (only) version of the ZY1276. Check the official YZXStudio store in TaoBao here: https://item.taobao.com/item.htm?id=549902607690 using Google Translate to translate the marketing blurb for the new meters:

FlashPilot · 2018-07-25T16:58:23.000Z

Thanks for taking the time to post your review. For my purposes, I just couldn’t justify the offerings from YZXStudio (although Ive almost pulled the trigger more than once). RD’s offerings make far more sense at their price point.

Are you still pleased with the meter?

bilakos10 · 2018-07-25T18:35:13.000Z

FlashPilot:

Thanks for taking the time to post your review. For my purposes, I just couldn’t justify the offerings from YZXStudio (although Ive almost pulled the trigger more than once). RD’s offerings make far more sense at their price point.

Are you still pleased with the meter?

Yeap, still absolutely pleased with it.
Recently I also used it combined with the company’s electronic load to benchmark some of my chargers and powerbanks.

Tomorrow I hope to get some free time to post my findings

duramax · 2018-07-25T18:39:47.000Z

This was a great review, many thanks. Didn’t know such a product existed.

bilakos10 · 2018-07-26T19:24:52.000Z

I updated OP with 5 Voltage/Current graphs (3 powerbanks and 2 Xiaomi chargers)

RD_tech · 2018-07-27T06:10:10.000Z

it is good meter , hope you like it

RD_tech · 2018-07-27T06:12:34.000Z

YZX usb meter is very good, but the price is too higher …
but RD (ruideng meter ) is cheaper and have more function.
for “”UM24C”:https://www.aliexpress.com/item/RD-UM24-UM24C-for-APP-USB-2-0-LCD-Display-Voltmeter-ammeter-battery-charge-voltage-current/32845522857.html?spm=2114.12010108.1000023.1.5aa25437tcldCc” and “”UM25C”:https://www.aliexpress.com/item/RD-UM25-UM25C-for-APP-USB-2-0-Type-C-LCD-Voltmeter-ammeter-voltage-current-meter/32855845265.html?spm=2114.10010108.1000023.3.39efe6d4UQtfqh”: , it can support PC software and android APP, APP can support 21 kinds languages
and
APP and PC software can export data by excel. it is easy to research the data…

but YZX meter did not have ,
For UM34C, it support USB 3.0 and Quick charge recognition mode:QC2.0、QC3.0、APPLE 2.4A/2.1A/ 1A/0.5A、Android DCP、SAMSUNG, support support OPPO phone VOOC, OnePlus DASH
Though UM34C and UM25C have Type-c port , but there is not trigger, only support type-c charge, not recognition

although for data or some function, it is not better than YZX meter, but for the price , it is already best …
for USB load, there are many choice , LD25/LD35
If someone need more cheaper meter, but colorful display, there is also choice
AT34

Waiting for everyone to discuss …

bilakos10 · 2018-07-28T18:48:16.000Z

Since quite a few guys are interested in the meter, here's a quick video of the process you have to go through to measure a USB cable's resistance.
www.youtube.com/embed/mY5AZ2KPL40

BlueSwordM · 2018-07-28T22:31:30.000Z

Wait, RDTech, the UM34C support VOOC charging pass through?

You’ve got a buyer now.

bilakos10 · 2018-07-29T03:42:25.000Z

BlueSwordM:

Wait, RDTech, the UM34C support VOOC charging pass through?

You’ve got a buyer now.

Not a representative of RDTech, but judging by the fact that the Type C port is rated up to 4A, it’s safe to assume that it will support VOOC just fine

RD_tech · 2018-07-29T14:16:20.000Z

yes, friend
it support …

Pfeffernuss · 2018-09-19T19:25:02.000Z

RD tech:

yes, friend
it support …

Received the UM34C today, plugged it into my OnePlus (VOOC/Dash) charger and it displays “Unknown”.

So it appears to not recognize/passthrough VOOC (here)…

BlueSwordM · 2018-09-19T19:45:35.000Z

I meant as a pass through.

That means you can monitor current when a phone supports Dash/VOOC charge. It’s one of the only USB meters which can do this.

It can’t recognize natively the protocol unless it is activated by the phone already.

Pfeffernuss · 2018-09-19T20:23:07.000Z

BlueSwordM:

I meant as a pass through.

That means you can monitor current when a phone supports Dash/VOOC charge. It’s one of the only USB meters which can do this.

It can’t recognize natively the protocol unless it is activated by the phone already.

I stand corrected! The device indeed passes through the fast charge signal (shown by the blue instead of “normal charge” orange LED on the phone) at >15W.

It does display QC2.0 though instead of Dash/VOOC but that’s no biggie.

Screenshot from phone app

Thanks for the heads up!

Edit: the 15W was with a longer USB C (Dash compatible) cable, with the original cable the result is even better (+/- 18W right now)

RD_tech · 2018-09-20T03:36:55.000Z

Pfeffernuss:

RD tech:

yes, friend
it support …

Received the UM34C today, plugged it into my OnePlus (VOOC/Dash) charger and it displays “Unknown”.

So it appears to not recognize/passthrough VOOC (here)…

Hi friend
I guess you misunderstand something , our meter show QC2.0 and QC3.O, for other mode , it only show unknow , but it indeed support , our device is a meter, not decide the mode, ok ? in fact , for any quick charge, you should check the voltage and current fit dash fast charger or not , ok ?

RD_tech · 2018-09-20T03:43:18.000Z

I don’t agree with you , our meter can support , there is not any problem, but our meter don’t show dash fast , because our meter only detect charge signal , ok ?
you can check the current and voltage fit that standard or not, ok ?
our meter is only a meter, not charger, don’t put all charger problem on our meter, ok ?
for example ruler, it is just tool, not decide your length, you have different hair style , different shoes, stand straight or not . those can decide your length, not the ruler, only the ruler range can decide it support 2M, 3m, or 4M, understand ?

RD_tech · 2018-09-20T03:43:27.000Z

BlueSwordM:

I meant as a pass through.

That means you can monitor current when a phone supports Dash/VOOC charge. It’s one of the only USB meters which can do this.

It can’t recognize natively the protocol unless it is activated by the phone already.

I don’t agree with you , our meter can support , there is not any problem, but our meter don’t show dash fast , because our meter only detect charge signal , ok ?
you can check the current and voltage fit that standard or not, ok ?
our meter is only a meter, not charger, don’t put all charger problem on our meter, ok ?
for example ruler, it is just tool, not decide your length, you have different hair style , different shoes, stand straight or not . those can decide your length, not the ruler, only the ruler range can decide it support 2M, 3m, or 4M, understand ?