WEB- U2 USB Meter/Monitor UPM Quick Look

Official specifications

  • Product Model: U2
  • Voltage measurement range: 4-24V
  • Voltage measurement resolution: 0.0001V
  • Current measurement range: 0-5A
  • Current measurement resolution: 0.0001A
  • Capacity accumulation range: 0-99999Ah
  • Energy accumulation range: 0-99999Wh
  • Temperature range: -40℃~180℃ / -40℉~356℉
  • Display screen: 1.77 Inch color TFT 128×160 display
  • Product size: 52.5mm x 34.5mm x 13.0mm

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Interface #1.1 Simple interface and large font
Interface #1.2 Six-digit display
Interface #2 Capacity and Energy
Interface #3 Equivalent Resistance
Interface #4 Fast Charging Protocols
Interface #4.1 Confirmation of Entering Trigger and Detection Menu
Interface #4.1.1 Trigger and Detection Menu
Interface #4.1.2 Trigger and Detection Menu
Interface # Auto Detection
Interface #5 Summary
Interface #6 Cable resistance measurement
Interface #7.1 V/A Curves
Interface #7.2 D+D- V/A Curves
Interface #7.3 Offline Data Curves
Interface #8.1 Settings
Interface #8.2 Settings
Interface #8.3 Settings

PC Program


You may need an on screen translator.


Current Accuracy (Brightness Level 1, Loaded)
V A Display A
5 1.00145 0.99942
1.50035 1.49757
2.00060 1.99643
9 1.00145 0.99944
1.50045 1.49725
2.00060 1.99652
12 1.00145 0.99958
1.50095 1.49784
2.00060 1.99642
20 1.00161 0.99957
1.50125 1.49823
Voltage Accuracy (Brightness Level 1, Unloaded)
V Display V (5 Digits) Display V (6 Digits)
5.04615 5.0448 5.04481
9.07260 9.0706 9.07061
12.1102 12.106 12.1067
15.1193 15.115 15.1156
19.9804 19.975 19.9758
Own Current Consumption
V mA, Display On mA, Display Off
Brightness Level 1, USB HID Port On
3.81 20.61 18.27
5.05 20.66 18.43
9.08 20.77 18.46
12.12 20.82 18.50
15.13 20.87 18.62
19.99 20.91 18.71
Brightness Level 1, USB HID Port On, w/ External Power
3.81 0.04 0.03
5.05 1.94 1.68
9.08 20.71 18.33
12.12 20.72 18.35
15.13 20.74 18.54
19.99 20.93 18.61
Brightness Level 1, USB HID Port Off
5.25 19.98 5.53
  • The accuracy of the current is good, but the voltage is not. The voltage needs to be recalibrated.
  • When brightness level is set to 1 and USB HID Port is on, own current consumption is around 21mA with display on and 19mA with display off. When USB HID Port is set to off, it becomes about 20mA with display on and 6mA with display off.
  • The internal resistance is about 32mohm (Includes both connectors).
  • The lowest working voltage is about 2.9V, but it needs to be read in the dark.


This UPM begins to consume external power once the input voltage is lower than the external supply voltage.

—- FW v2.4 —-

  • It behaves like a source with power limited when it triggers/requests the last PPS APDO. When the requested output voltage exceeds the nominal Prog voltage, the it limits the requested output current such that for a PDP Rating of x Watts the requested output current limit is calculated as RoundDown (x/requested output voltage) to the nearest 50mA. So you won’t get the max power even if the source is not PPS power limited.

UPDATE 8/14/2018

  • I overestimated its algorithm. When the requested power (output voltage * max output current) exceeds the PDP, it limits the requested output current such that for a PDP Rating of x Watts the requested output current limit is calculated as RoundDown (x/requested output voltage) to the nearest 50mA. Let’s say, PDP = 30W, Requested Output Voltage = 11V, and the Requested Output Current will be PDP/Requested Output Voltage = 30W/11V = 2.73A RoundDown to the nearest 50mA = 2.70A. So you won’t get the max power even if the source is not PPS power limited.


It has some software issues when powered by an external power source, but no such issues without an external power source.

The PD Listener loses packets even when using external power and operating correctly.

Ah and Wh calculation errors. This happens when USB HID PORT is turned off and the screen is off. Some data seems to be missing when the screen is turned off.


The highlights of this UMP are the interesting action recognition and g-sensor. Other than that, the rest is not very impressed. The factory voltage calibration is not done well. And the own current consumption is a little bit high when the USB HID Port is on. Also, the performance of drawing curves is not very good. In addition, the PC program is very simple and crude. However, new firmware is released often. Hope some of the issues will be fixed in the future.

Mutual Support

The following is a list of files discovered, created, modified, or provided by U2 users to help others. If you are a U2 user and would like to add your work to this list, please leave a comment or contact me.

Thank you all for your hard work!


31 thoughts on “WEB- U2 USB Meter/Monitor UPM Quick Look

  1. PC software 4.0 is available, same link as 3.0:
    The new software version requires firmware 5.5 to connect, so don’t try to use it if you have a fake U2!
    Lang.ini has a few new strings, the English translations are easy to obtain with Google Translate.
    My U2 is genuine, firmware 5.5 introduces a new line in the auto-detection screen listing the PD modes. With older firmware you had to enter the trigger mode to see the modes.


  2. Firmware version 5.5 was released (Release note translated whit google):
    1. Optimize the automatic detection interface UI
    2. Reserve Bluetooth APP upgrade interface


  3. Firmware version 5.4 is out on the same link with following changes:

    2019-01-30: V5.4 (New Year’s Edition, I wish you a Happy New Year)
    1. Optimize Emark detection
    2. Amend some typos
    3. Improve the MFI test process


  4. Official software support:

    U2 Manual:http://www.witrn.com/witrn/u2/WEB-U2_userguide.pdf

    U2 PC Software v2.3:http://www.witrn.com/witrn/u2/U2X上位机和升级软件V22SP3.rar

    U2 Firmware v5.2:http://www.witrn.com/witrn/u2/U2_固件.zip


  5. Here is changelog ytanslated by Google:
    2018-9-6: V3.4
    1. Optimize PD protocol to improve PD direct charge mobile phone compatibility
    2. Optimize other details
    2018-9-18: V3.6
    1. Optimized for automatic detection and identification of Kunxing PPS charging head
    2. Fix the PD sniffing interface into the voltage constant bug
    2018-10-09: V4.0
    1. Optimize the identification of the latest PPS headers
    2. Optimization Q4+ new head recognition logic
    3. Adjust the SAMSUNG 5V 2A test standard


  6. Hi, tank’s for your work and your help (sorry for my english…)
    On amazon spec, he have wifi “802.11abg” and bluetooh logo on his back, how to use it ?



    • Hello Jimmy,

      Nope, there is no wifi nor bluetooth available on this meter so far. It’s just a PCB without a wifi or bluetooth module. Bluetooth connectivity will appear in a future firmware upgrade, but you will need to purchase their bluetooth module.

      Hope this answers your question.


  7. Thanks again Magicmeter! With the lang.ini we have the U2Meter.exe in ENGLISH!!! Fantastick guys! We can make some of the Chinese products a decent product! I wish they have done this on their own! But thanks to you all supporters, I have mine on version V3.3 and in English!


  8. Hello,
    firstly I want thanks for nice videos.
    I order this meter via Taobaoring and they said that they will get firmware and software from seller but they didn’t sent it to me for longer then month. Do you know from where I can get new firmware and software?
    Also there is bluetooth but I cant see for what it used as I think only cable is used to connecting to PC.


    • I got everything from my seller. I will give you a link to the package I received.

      Yes, only cable connection is available so far. Bluetooth connectivity will appear in a future firmware upgrade, but you will need to purchase their bluetooth module.


  9. Great details and nice documentation! Do you know if this unit can be programmed? If yes, how is it done? I just purchased one but it came with a very old version and lots of chinese characters, so I’m not happy with it. Do you know, or someone who does know how to update the firmware? Thanks! Tony PS: Sorry, do not have a website so I uploaded a very bad video to youtube – that is what put in its place.


    • Hello Tony,

      Q. Do you know if this unit can be programmed?
      A. The WEB- U2 can be programmed, but only the developer can do this. It is not open source.

      Q. Are all of these devices just the exact same copies under many names?
      A. Nope, they are different. Different brands and different developers.

      Q. I’m sure they all can use the same firmware – or am I wrong?
      A. Since these devices are different, they cannot use the same firmware.

      Q. Do you know, or someone who does know how to update the firmware?
      A. Please contact the seller first. S/He should provide you with the software package and instructions.

      How to Change the System Language on WEB- U2

      1. Press and hold the M button and then connect U2 to a power supply.
      2. Release the M button when you see the setting menu.
      3. The 01 option is used to set the language, so long-press the M button to enter.
      4. Select a language you want, and then long-press the M button to save.
      5. Finally long-press the OK button to exit.

      Hope this answers your questions.


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