New USB-C Charging Meter from Plugable

USB-C charging demystified.

One of USB-C’s great potential features is the ability to charge in either direction, with much higher power levels than was previously possible with USB (up to 100 Watts). But USB-C is still maturing, and there are many combinations of chargers and devices which either don’t charge, or charge at a lower rate. And if you’re a hardware designer or tester you need to be on the lookout for unexpected results or problems. Plugable’s new USB-C power meter is an inexpensive solution.

The USBC-VAMETER is a compact USB-C multimeter designed to quickly show how your USB-C devices are behaving under a variety of scenarios.

The Plugable USBC-VAMETER is roughly the size of the average USB flash drive and was designed with portability and ease of use in mind, only showing essential information that users of all skill levels can understand. With three major points of information the VAMETER can quickly show how fast a device is charging by indicating voltage, amperage, and in addition the direction in which the electrical current is flowing. Users can calculate how much power a device using this simple formula: The power P in watts (W) is equal to the voltage V in volts (V) times the current I in amps (A), P = V × I.

Here you can see that the voltage is reported as 14.5V and the amperage is 1.77A which calculates to 25.66 watts. This would indicate that the system is charging at almost the maximum rate (29W for the model system the USBC-VAMETER is attached to).

The VAMETER is bidirectional and can be connected in any direction and it will indicate in what direction power is flowing. This is useful when you’re not sure if a device is drawing power, or pulling power. We took special care when designing this product to ensure that it acts as a transparent interposer – which means it should not interfere with the USB data (1.1 through 3.1 Gen 2), USB-C Alternate Mode video, or USB-C charging. It can be used inline with USB-C docking stations, chargers, USB-C accessories, etc. The meter is able to achieve this without interfering with normal USB-C operation as it only taps into the power (VBUS) and ground connections to measure their values and leaves all of the data lines untouched.

Common use scenarios would include the following:

  • Connecting between a USB-C host system like a laptop, tablet, or cell phone and a charger to monitor charge information.
  • Connecting between a USB-C host and docking station to monitor charge information.
  • Connecting between a USB-C host system and a USB-C bus powered accessory like an external hard drive, flash drive, etc to measure power draw of a device.
  • Testing for USB-C port spec compliance such as a VBUS hot condition, voltage drop under load, etc.

Where to Buy

11 comments on “New USB-C Charging Meter from Plugable”

  1. Joshua Henry Reply

    Hi Albert, Thanks for asking! We do not have a USB-A equivalent but you could use some USB-C to USB-A adapters with this product. During our testing we used a combination of USB-C to A adapters to essentially convert this meter into a USB-A version, but we don’t particularly recommend this as there are already a number of dedicated USB-A meters on the market that work very well.

  2. Wilkey Reply

    Is there anyway to invert the digital display? The product page on Amazon where I bought this shows right side up text when plugging in from the left side of the device. However, when it is plugged into the left side of my MacBook Pro, the digits are upside down. Thanks!

  3. Wilkey Reply

    BTW, I would add that when it is between my Anker USB-C hub and the MBP, my drives connected to the hub do not show up. It’s pass through charging my laptop, but the drives never mount. However, when I connect it between the wall and the hub, my drives mount and MBP charges as before.

    • Joshua Henry Reply

      Hi Wilkey,

      Thanks for asking. Unfortunately there is not. We’re looking to correcting the image to reflect the actual screen orientation. Sorry for any confusion there! For the Anker hub not working right, try fipping the USB-C connector 180 degrees and see if that helps.

  4. Wilkey Reply

    Oy, I’ll give it a try, but that means the display will be facing the tabletop so then I won’t even be able to see it. Let me ask this: will the VAMeter work properly when using a USB-C extension rated for a minimum of 20V 3A? I like the functionality of the meter but I have to find a way to set it up so that I can see the display from my seat. PS, what’s the approximate power consumption of the device itself?

    • Joshua Henry Reply

      Hi Wilkey, I mean flip whatever is connected into the USBC-VAMETER 180 degrees. It should work fine with an extension if the cable is built to USB-IF specs. The unit itself uses very little power, under 100mA.

  5. Wilkey Reply

    I tried it and here’s what I found. When I flip over EITHER the VAMeter going into my MBP OR the USB-C cable going into the meter, the drives are detected. Wow. While the USB-C connector is orientation insensitive, apparently what you wish to do with the connection is not. Anyway, really enjoy the VAMeter. Great build quality and clean display interface.

  6. Wilkey Reply

    BTW, I wanted to comment perhaps to inform any future revisions to the product.

    The orientation of the display on the shipping product *should* have been as depicted in the Amazon product page images. One reason has to do with Apple products in particular. Current MacBook and MacBook Pro have USB-C/Thunderbolt ports on either the left side only or both sides. On the MBP 13, only the two ports on the left side of the laptop can operate at the full speed of the TB3 spec because of internal controller/bus limitations. Thus, with my late-2016 MBP with TouchBar, I run the USB-C hub (and incoming TB3 dock) into a left side port to provide power as well as connectivity to my external drives including the Time Machine volume.

    This is optimal and really the only way to fulfill the promise of a “single cable” clean system.

    An additional factor that is not strictly Mac-related is that the majority of people, and by extension, computer users, are right handed. This means if a mouse is used, it will be on the right side of the keyboard. Having the laptop stick out on the right hand side intrudes into the space where mousing takes place.

    I’m sure you guys had sound engineering reasons for orienting it the way you did, but I just wanted to let you know my usage scenario. I don’t suspect it’s unique.

  7. Wilkey Reply

    Oops, typo. You may edit my last comment “Having the laptop stick out on the right hand side…” to “having the VAMeter stick out on the right hand side of the laptop…” and delete this comment.

  8. Wilkey Reply

    Well, it’s been a little while and recently Josh contacted me to test a revision to this device. I just received it and am pretty pleased to say that the display on the new unit has been inverted so that it reads right-side up when plugged in to the left side MBP ports. Initial observations show the voltage and current indications to be consistent with the older unit. I’ll be doing a little further testing to make sure there are no data or connectivity issues but if there are, I will report back.
    Thank you, Plugable, for being responsive in considering and effecting a helpful change. I know that you guys make good products…now I personally have experienced that you make them even better.

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