YEREADW USB-C Tester Power Meter Review: Diagnose a Bad Port, Cheap

I bought the YEREADW USB-C Tester Power Meter specifically to diagnose a bad charging port. That use case has paid off. I have since left the meter inline on my desk charger, and even when I am not actively testing something, I find myself glancing at the screen. The screen shows you exactly what your charger and cable are pushing into your phone, your watch, your power bank — wattage in real time. For a gadget that costs less than a sandwich, it is the most useful $12 debugging tool I own.

What it is

The YEREADW USB-C Tester Power Meter is a small inline module the size of a matchbox, with a USB-C plug on one end and a USB-C socket on the other. You put it on the cable: charger → meter → cable → device. The meter shows you live voltage, current, and wattage. Most variants of this kind of meter also show accumulated mAh, elapsed time since plug-in, peak wattage, and the negotiated PD or QC protocol on the cable.

The specific model I bought is the YEREADW KWS-2303C. It is a 4 to 30 volt, 0 to 12 amp range, which covers every USB-C device I have including laptops that pull 100 watts. The display is a small color LCD with three or four fields visible at once. It comes with a small carrying pouch. There is no app, no pairing, no batteries — it draws a tiny amount of power from the cable itself.

The screen shows what I wanted to see: live voltage, live current, and a derived wattage number. It also shows accumulated mAh over the charging session. That last field is the one I did not know I wanted — it is a clean way to confirm how much a power bank actually pushed into your phone, or how much current a wireless charger pedestal is delivering over the course of a night.

Why I bought it

A USB-C port on one of my devices started flaking. It would charge intermittently, the connection felt loose, and I could not tell whether the port was going bad, the cable was going bad, or the charger itself was the culprit. I bought the YEREADW to find out.

The diagnosis took 90 seconds. I plugged the meter in, plugged in the suspect cable, plugged in the suspect device. The voltage reading was sitting around 4.5 volts under load on a port that should have been 5 volts clean. That is a dying port. I swapped the device to a different USB-C port. The meter immediately showed a clean 5.0 volts with the same cable, the same charger. Bad port confirmed, port avoided, problem solved. The meter paid for itself in that single test.

Living with it

I never removed the meter from the cable after that first test. It lives between my desk charger and my main work cable, and I look at the screen roughly every time I plug in a phone or a pair of earbuds.

When I plug in a phone, the meter shows a brief negotiation spike (the phone and charger settle on a voltage and current), then the screen settles into a stable wattage. A 30-watt phone charger can sit anywhere from 18 watts to 27 watts depending on the phone, the cable, the battery level, and the temperature of the phone. The meter shows all of that. There is a version of “is this charger still as fast as it used to be” that you can only answer with this kind of device.

When I plug in my smartwatch charger, the meter shows a stable 5 watts or so, which is normal for a wearable. The point is not that the reading is exciting — the point is that the reading is visible. Watching 5 watts arrive cleanly tells you the dock is fine. Watching the voltage sag tells you the cable is flaky. Watching a power bank deliver 18 watts slowly dropping over 90 minutes tells you the battery in the power bank is hitting its voltage sag point. These are all things the meter surfaces in a glance.

I also tried the meter in the cable tester role. It is not a real cable tester — it does not measure resistance or continuity or signal integrity. What it does is show you what a cable will pass. A bad cable with too-high resistance or a marginal wire will show up as lower than expected wattage. I confirmed one of my Anker cables was dropping voltage badly enough to slow-charge a phone that should have been fast-charging. I replaced that cable. Again, the meter paid for itself.

What I like

• Live V / A / W readout of exactly what your charger-cable-device chain is doing.
• Pass-through USB-C. No need to unplug or otherwise change the chain to use the meter.
• Useful for both diagnosis and idle curiosity. The “I just want to see what is happening” use case is half the value. You find yourself watching how much power the watch charger pulls, or the laptop, or the AA battery charger, or the in-car charger.
• Compact enough to leave inline. The meter box is chunky for what it is — larger than a normal USB-C connector — but it is small enough that it can stay attached to your cable on the desk without getting in the way.
• Bidirectional. Both ends are USB-C, you plug in either side. No “this end goes to the charger, that end goes to the device” mistake to make.
• Cheap. I paid $12-something for it. It is below the threshold for thinking about whether to buy it. If you have ever wanted to know why a device is slow-charging or why a power bank feels like it is not hitting its rated output, this is the price point.
• No batteries, no apps. It draws a tiny amount of power from the line and uses an LCD with no backlight. The one-button interface is a single physical switch on the side that rotates between display modes. No Logi Options, no Bluetooth pairing, no account.
• Confirmed a dying port for me within 90 seconds. That is the headline use case and the meter delivered.

What annoys me

• A lot of information on a small screen. The LCD shows voltage, current, wattage, accumulated mAh, elapsed time, and the negotiated protocol — six numbers on a screen the size of a postage stamp. At a glance, it is fine. To read precisely, you have to lean in.
• I could not find a clean way to change what is on the main screen. The single side button cycles through display modes, but none of them hides the dense field set. There might be a way to customize — the listing mentions a setting — but I have not dug in to find it.
• Bulky for what it is. The plug body is two to three times as thick as a bare USB-C plug. It will not seat cleanly next to another device on a flush charger. On multi-port chargers I had to give the meter the outside port so it does not physically interfere with the port next to it.
• Can be unplugged accidentally. If you are juggling the meter and a thick cable, the meter can come out of the charger mid-charge. Not dangerous, but worth knowing if you leave it inline.
• No logging or export. The screen is the only output. There is no app to capture the data, no log file, no way to graph a charge over time. For a quick diagnostic glance that is enough. For “I want to see my overnight charging curve” it is not.
• Protocol detection is not always accurate. It claims to display QC / PD / PPS protocol. In my testing the negotiated protocol field sometimes shows a vendor-specific code instead of a human-readable protocol name.
• Screen is hard to read in low light. The LCD has no backlight. In a dark room the screen is very dim. There is no “hold the meter up to see the reading” problem, but you do need some light.
• Not waterproof. Drop it in a sink and you are done. This is true of most electronics, but inline meters often sit near spills because they dangle from a cable.

Who it is for, who should skip it

This is the right tool for anyone who has ever looked at a USB-C device and wondered whether the charger, the cable, or the device was the cause of a slow or broken charge. If you have a dead or flaky port and you want to know which one without swapping parts, this answers the question in under a minute. It is also a fun thing to leave inline if you are the kind of person who likes looking at the numbers — voltage under load, the slow ramp of current as a phone negotiates a fast-charge, the mAh count after a full charge cycle.

Skip it if you only charge from one outlet and you have never had a charging problem. Skip it if you need a real cable tester that measures resistance or protocol-layer signal integrity. Skip it if you want a meter that logs to a phone app — get the BLE-equipped variants for that.

Verdict

For $12, this is the kind of diagnostic tool that is so cheap it is silly not to own one. It diagnosed a bad charging port for me within a day of being unboxed, and I have used it daily since to keep an eye on what my charging chains are doing. The bulky body and dense screen are real caveats. The single most important fact about this meter is that, in a year of use, I have never once been disappointed by what it told me.

Grade: A. Easy recommendation at this price point for anyone who charges USB-C devices.

For the nerds

• Model: KWS-2303C, sold by YEREADW.
• Range: 4 to 30 volts DC, 0 to 12 amps. Wattage shown up to 360 watts (V × A), which covers every USB-PD profile through PD3.1.
• Readout: Voltage, current, wattage, accumulated mAh, elapsed time, peak wattage, negotiated protocol (QC 2.0/3.0, PD 2.0/3.0, PPS, VOOC, FCP, SCP).
• Power draw: Quoted at under 5 mA. The meter pulls a tiny amount of current from the line it is monitoring. I have not seen it cause a charger to fail to negotiate a fast-charge profile.
• Display: Color LCD, no backlight, ~1.4 inches diagonal. Single side button to cycle through screens.
• Pack: USB-C male on one end, USB-C female on the other. The meter body is aluminum-and-plastic with a small carrying pouch in the box.
• No app, no pairing, no batteries. All monitoring is on-device.
• Not a real cable tester. Measures what a cable will pass, but does not measure resistance or signal integrity in the way a professional cable tester does.
• What I would change: Better screen — give it a backlight and let me pick which two or three metrics are on the main screen. Smaller body — the plug-in module is bigger than the connector itself by a lot.
• Caveats on protocol detection: The “current protocol” field sometimes reports a vendor code instead of a human-readable protocol name. The wattage and amp readings are still correct.

Check the current YEREADW USB-C Tester Power Meter (KWS-2303C) price and availability on Amazon.

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