USB 3.0 Tester, Eversame IPS Color Display Digital Multimeter Voltmeter Current and Voltage Monitor, DC 5.1A/30V/150W Power Meter Tester, Test Speed of Chargers, Cables, Capacity of Power Banks-Black

This compact tool has proven to be indispensable in my arsenal of repair equipment. It's incredibly useful for quickly identifying whether a device is receiving power properly, which saves me a ton of time and frustration. I appreciate its ability to eliminate guesswork by instantly indicating whether there's an issue or not, because I can't stand fumbling around with multiple cables, trying to diagnose a USB problem.However, there is one aspect where it falls short, data passthrough. Not being able to monitor the voltage and amperage while USB devices are in use can be somewhat limiting if want to keep track of fluctuations during use. Nonetheless, considering its affordability and ease of use, this USB Voltmeter remains a fantastic addition to my toolkit.

tells you what you want to know, good and inexpensive.

Works great!NOTE: this review is for the black "USB Safety Tester" version without a cord.There are 3 screens to cycle through:1) Big voltage, big current, watts, cumulative time, cumulative amphour, cumulative watthour2) voltage of all 4 pins (v-, d-, d+, v+), resistance (presumably between d- and d+), temperature, time, current3) ((redundant info found on screen 1 and/or 2))This meter works with quickcharge cables/supplies showing voltage >5V.Showing the voltage/resistance of the d- and d+ pins is great as it allows you to identify a capacity/type of charger connected.The screen is very poor quality. The viewing angle is almost nothing, you need to be looking right at it to read it.The A connector is reversable so you can connect it either way (up or down), useful if you have a laptop/plug that would otherwise result in the screen facing away from you. Note this makes the connector quite fragile as the plastic blade inside the connector is extremely thin and has 2 sets of pins on both sides.While the connector is reversable, the screen is not so you can end up viewing the screen but everything is upside down.The mode button also, when held, will reset the cumulative timers, and in doing so also make a horrible beeping noise (the beeping is also sounded when first powered up). I wish there wasn't a beep, it's quite annoying.

I bought this for developing my apartment emergency power system. The voltage and current readings were compared to a certified and calibrated fluke meter, and was roughly 1 to 2 percent off. Great accuracy.This handled the full 18 watts for Quick Charge 3.0 effortlessly.If you are a tinkerer working with USB power, this would be a great addition to the bench.

Nice USB monitor. I use it to monitor the charging performance of my solar panel and regular plug-in USB chargers. There are quite a few screens but I attached an annotated picture of the screen I find most useful. On this screen, you get a dashboard view of the charging performance, including:- Input voltage. For USB should be about 5 volts, plus or minus a few %- Input amperage - the larger the number, the faster the charge. This number is device-dependent. The charger will attempt to negotiate the fastest speed the device being charged can handle. Usually this is between 0.8A (slow) to 2.4A (fast)- Cumulative Charge in mAh - total amount of charging current passed though since reset (in mAh). If you're charging a 8000mAh power pack, for example, this number will go up to about 8000 (0-100%)- Cumulative Charge Time since reset- It also displays 3 other numbers which I find not as useful: total charge in W, Wh and charging temperatureOne thing I wish this had is a pigtail to on the male end to connect to the USB charging port. It doesn't, so I purchased a separate short USB extension cable (6in USB 2.0 Extension Adapter Cable A to A - M/F) for this purpose. Based on my test this doesn't reduce the charging performance.Attached is an annotated picture of the dashboard screen I find most useful, as well as the instruction sheet it came with. Instructions are a little difficult to understand due to translation.

Electronic devices are expensive! With new advances in battery technology it's quicker than ever to charge your items but there is a HUGE disparity in quality between cables and chargers. Some chargers and cables are so poorly made they can actually damage the device they are plugged into and cheap cables will make a HUGE difference in how fast the items will charge.This little digital power meter is a great device. With this I was able to determine that my stock Samsung "Fast Adaptive" charger was no longer putting out rated voltage and replace it with a better made aftermarket charger. This is also great for testing cables. Plug the Power Meter into the USB charger then plug the device to be charged into the cable you wish to test then into the Power Meter. I've been AMAZED at the difference between cables! As much as a full 1.5 volts difference! You'll also receive other useful information such as time until device is fully charged, wattage and more.The only complaint I have about this item is the lack of any sort of manual but luckily reviewer Opiedog came to the rescue in another post here called "The Missing Manual - J7-t (abridged)" which answers a lot of questions.Well worth the cost to have in your toolbox or in a drawer to answer questions about cables, chargers and battery packs. It might just save your phone!