YOJOCK J7-C USB-C Tester & Power Meter Review

I recently reviewed the superb Anker 737 Power Bank, which is the only power bank that has 140W PD 3.1, making it suitable for the Macbook Pro 16”. I have also reviewed many new power delivery plugs that claim to do 65W, 100W or 140W power delivery and a few portable power stations with 100W PD input/output.

So being able to measure the input/output of these devices is quite important. USB power meters are handy little tools for anyone that needs to check the power delivery performance of electronics.

In the past, I was using an Innovateking USB-C Tester, which was UBS-C only and claimed to measure 0-4A 3.7-30V. This meant it could handle up to 120W, and I paid £15 for it back in 2021.

I seem to have lost this in the mess that is my office, so I recently bought the Yojock USB-C tester for the same price, but this tester has USB-C, USB-A and microUSB making it a bit more useful for testing a wide range of devices.

Cheap vs Expensive USB-C Voltmeter Tester / Power Meters

At £15, it was cheap enough to be an impulse buy that I didn’t need to think about,

When looking on Amazon, there were options going up to £80, which can be linked up to a PC for more thorough data logging.

You then have a lot of options in the £30+ price range that have varying features.

My initial assumption was that the cheap options, such as my Yojock, wouldn't be able to handle the new higher-power delivery devices. However, this can go up to 32V and 5.1A for a theoretical peak 163W input/output. However, the measuring range is officially listed at 150W, which is higher than any power delivery charger on the market, therefore making it suitable for my needs.

One of the £30+ options I looked at is capable of 4.5V-50V and 50mA-6.5A, giving 325W but claimed support of USB-PD R3.1 Extended Power Range (101W-240W).

You then have the Innovateking-EU FNB48 for around £38. This does 4-24V and 0-6.5A with a monitoring capacity of up to 156W. That doesn’t seem like good value for money, but the main difference is that it supports multiple fast charging protocols, including:

• PPLE 2.4A, QC2.0, QC3.0, PD, Samsung AFC, Huawei FCP, Huawei SCP, VOOC/WARP, SuperVOOC, and MTK-PE.

This, therefore, makes it compatible with the likes of OPPO/Realme/OnePlus and Huawei.

Due to me testing a lot of devices, I probably should have bought one of the better power meters, but this works for now and I will inevitably lose it.

Specification / Features

• The USB tester can detects voltage, current, capacity, electric quantity, power, temperature, resistance, charging time and other data of the USB or type C port devices.
• It can also be used to test the capacity and electric energy of a power bank. Measuring voltage: 3.6V-32V; measuring current: 0-5.1A.
• The USB power meter comes with A OTG adapter
• It supports PD3.0/PD2.0, QC3.0/QC2.0 and BC1.2
• Support for iPhone includes 13/12/11/X/iPhone Xs quick charging, 29W power, 5V3A/9V3A/12V2.5A/15V2A
• This USB C tester features over-voltage protection, over-current protection, under-voltage protection, low energy protection. This upgraded USB Type C tester can detect safety and maximally protect the appliances from damage

Inputs / Outputs

This has input and outputs for:

• USB-A – Input/Output
• USB-C – Input/Output
• Micro USB – Input only

Measurement Specification

	YOJOCK USB C Tester USB Power Meter
Voltage Measuring Range:	3.6 ~ 32.0V
Current Measuring Range:	0.00 ~ 5.1A
Capacity Cumulative Range:	0 ~ 99999mAh
Power Cumulative Range:	0 ~ 999999Wh
Power Measuring Range:	0 ~ 150.000W
Resistance Measuring Range:	1 ~ 999.99Ω
Max Timing Range:	999H : 59M : 59S
Working Temperature:	0-80℃ / 14-140℉
USB D+ Voltage Range:	0 ~ 2.999V
USB D- Voltage Range:	0 ~ 2.999V
Measurement Rate:	0.5times/s
Self-consumable Current:

In Use

The button on the tester provides such a basic functionality:

• Short press to switch different interface
• Quick 2 Press: Reset capacity (mAh)
• Quick 3 Press: Reset energy(Wh)
• Quick 4 Press: Reset timing (00:00:00)
• Quick 5 Press: Change group number (NO.X, total 10 groups of data)
• Long Press to reset capacity, energy and timing of current group(mAh, Wh, 00:00:00)
• On the system interface, short press the key to switch different setting options, long press the key to select and enter the option.

Testing Peak Power Delivery Input / Output on Different Devices

For most of the tests, I used the 140W rating USB-C cable that came with the Anker 737 Power Bank. For the Realme test, I used the included cable for the charger.

• Redmagic 8 Pro:
  • Expected: 65W
  • Result: 60.38W
• Pixel 6:
  • Expected: 22.5W (even though the charger claims 30W)
  • Result:
• Pixel 6 Wireless Charger:
  • Expected: 21W
  • Result:
• Realme GT Neo 3T:
  • Expected: 80W
  • PD Charger: 18W
  • Supplied Charger: 78.6W
• Anker 737 Power Bank:
  • Expected: 140W
  • Result:120.38W
• Huawei Matebook 13:
  • Expected: 65W
  • Result:
• EcoFlow RIVER 2 MAX:
• Ugreen Nexode 140W GaNFast Charger (charging the Anker):
  • Expected: 140W
  • Result:

Overall, I was happier with the results than I expected. I wasn’t sure the meter would pass through or read the correct values for Realme, as they use a proprietary charging standard.

The Ugreen Nexode 140W shows a lower-than-expected value, but I was only able to achieve a bit over 120W when charging the Anker 737 Power Bank.

Price and Alternative options

I paid £14.90 for the Yojock USB-C tester, and it is one of the best and most reviewed options on Amazon. There are cheaper options, especially if you only need USB-C only, but for the sake a few pounds, I’d say this is worth the extra.

As highlighted at the start of the review, there are quite a lot of alternative options which cost more money but have a better specifications:

• AVHzY 3 in 1 Power Meter – This is an interesting option because it also adds DC5.5 input/output, and it has Bluetooth allowing it to transmit the data readings to an app.
• AVHzY CT-3 / CT-3A / CT-3L – This brand has three options ranking from £60 to £80. All the models can do 26V/6A (156W) though the listing states maximum power of 65W Max 100W guaranteed
  • The CT-3 supports both USB-C and USB-A input and output (the C3 model only has USB-C input/output)
  • The CT-3L includes a test load module which is programmable via the actual CT-3 module.
• Plugable Store 240W USB-C Power Meter – The only has basic functionality, but it is one of the only options that can go up to 240W with the SB-PD R3.1 Extended Power Range

Overall

For the price, the Yojock USB-C tester is excellent and exceeded my expectations, being able to read the correct power for the proprietary charging standard from Realme.

In hindsight, I probably should have paid extra for a tester with more features, but for most scenarios, especially when only testing the power delivery standard, this works perfectly well.

Last update on 2023-06-01 / Affiliate links / Images from Amazon Product Advertising API