Diagnose your charging woes with Plugable’s tiny power meter [Review]


Plugable USBC-VAmeter review
The Plugable USBC-VAmeter tests the quality of the connections between your computers and chargers and other peripherals.
Photo: Ed Hardy/Cult of Mac

Your MacBook isn’t charging right and you can’t figure it where the problem is? Plugable’s USBC-VAmeter can help. Connect it to the power cable running to your Mac, iPad or iPhone to see the voltage, wattage and amperage.

I’m no electrical engineer, but I tested this miniature power meter. I found it both useful and kind of fun.

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Plugable USBC-VAmeter review

Suppose you have an accessory that’s not connecting. Is it even getting power? Connect the USBC-VAmeter and you’ll find out. Check to see which USB-C cables can handle the most current. This is also a quick way to see if something is wrong with your Mac, iPhone or iPad charger.

But there’s an important caveat. “This meter is not meant to replace professional USB-C test equipment; it is designed for quick/easy measurements for users of any skill level,” warns Plugable.

Hardware and design

The USBC-VAmeter is quite portable. It’s small enough to tuck into a gear bag, ready to be pulled out whenever you need it. Specifically, it’s 1.2 inches by 0.9 in. by 0.4 in, and less than half an ounce.

There’s a USB-C port on one end and a USB-C connector on the other. To test power flow, plug the meter into your Mac or iPad, then attach the cable cable.

I’m testing a new second-generation Plugable USBC-VAmeter. This has a brighter screen than its predecessor. And there’s now a button to rotate the screen so the information points toward the user.

Plugable USBC-VAmeter version 2 has better ports and a brighter screen.
The Plugable USBC-VAmeter is very portable — about the size of a USB drive.
Photo: Ed Hardy/Cult of Mac

Plugable USBC-VAmeter performance

This multi-meter can handle from 4V to 20V and 50mA to 10A. It supports USB 1.1 through USB 3.1 Gen 2.

It’s not compatible with Thunderbolt. But that’s an issue with data, not power. “No damage will be caused, but due to the extremely high bandwidth of Thunderbolt 3, you may encounter instability through Thunderbolt 3 accessories connected through this meter,” warns Plugable. “It is only designed to officially support USB 3.1 Gen 2 speeds at 10Gbps, not the 20 to 40Gbps of Thunderbolt 3.” (Note that Thunderbolt 4 didn’t bring significant changes for Mac users.)

In other words, you can use the accessory with your Mac, but it might interfere with very high-speed data connections. That’s not going to mater if you’re testing the wall charger.

I can confirm that the USBC-VAmeter doesn’t interfere with data running through the USB 3.1 cables it’s testing. It only taps into the power (VBUS) and ground connections.

Plugable’s little accessory displays voltage, wattage and amperage. Just as importantly, it shows the direction of power flow.

I’m not an electrical engineer, so my experience with those terms dates back to a single class I took at university. As such, I can’t take full advantage of the USBC-VAmeter’s capabilities. And an electrical engineer might want something more professional. Plugable warns the multimeter is +/- 3% to 5% inaccurate.

But even with my limited electrical knowledge I found it useful to be able to check whether my devices were getting power. And no real expertise was required to find out that one of my USB-C cables can’t handle anywhere near as much current as the others.

Plus, using this gadget is just interesting. For example, I’ve read that my iPad draws less power as the battery level gets closer to 100%. I can confirm that — the tablet draws about double the amps at 55% as it does at 95%. And I found myself testing all my gadgets to see how much power they use.

Plugable USBC-VAmeter final thoughts

The USBC-VAmeter is a handy little multimeter for non-professionals who want an easy way to look for electrical problems with their Mac, iPad or iPhone.

I found it useful and actually kind of fun.


Plugable sells the USBC-VAmeter through Amazon. The price is $29.95.

Comparable products

An alternative is the KJ-KayJI 2-in-1 USB Tester ($20.99). This can test both USB-A and USB-C. Given the lower price and additional capabilities, this might seem like a slam-dunk but I can’t recommend a product from a company I’ve never heard of before. I’ve tested many Plugable products in the past and they’ve always performed brilliantly.

Those looking for something more professional should consider the Klein Tools ET920 ($47.98).

Plugable provided Cult of Mac with a review unit for this article. See our reviews policy, and check out other in-depth reviews of Apple-related items.