Test/Review of USB meter: QC2-3-MTK-PE Trigger J7-t

USB meter: QC2-3-MTK-PE Trigger J7-t







Official specifications:

  • Standard QC2.0 quick charger tester for testing car charger, mobile power charger reaches a predetermined

  • Fast charge current standards for: 5V, 9V, 12V, 20V

  • Standard QC3.0 quick charger tester for testing car charger, mobile power charger reaches a predetermined

  • Fast charge current standards for: 5V, 9V, 12V, 20V, 0.2V increment or decrement whether

  • MTK-PE standard quick charger tester for testing car charger, mobile power charger reaches a predetermined

  • Fast charge current standards for: 5V, 7V, 12V.


I found this unit on Aliexpress at a dealer called honestycentre.



How does it look















The button has multiple functions:
A long press will change between QC2, QC3 and MTK-PE
In QC2: A short press will change between 5V, 9V, 12V and 20V, a double presss will cycle automatic between modes.
In QC3: A short press will decrease voltage, a double presss will increase voltage.
In MTK-PE: Same as QC3, also be aware that this requires a load on the output to work.

5 fast presses will reset the Ah, mH and time counters.
Holding the button down when connecting power will enter the configuration and calibration menu.



The two QuickCharge screens



And the MTK PE screen



I could break it open without any damage.





This design looks very simple. It has a voltage regulator, a R050 for current measurement, a processor and some transistors for turning the output on/off. The missing 6 pins chips are probably ADC’s with better resolution, the missing 8 pin chip is a EEPROM.









Measurements



This device requires nearly 4 volt to work fully, this will affect the precision at low voltage including QC3 when at lowest voltage. When the voltage is 4 volt or above the precision is good.
  • The usb connector is reversible, this way it is always possible to connect with display up.

  • Own current consumption is 20mA

  • Internal resistance is about 0.17ohm including connection resistance.

  • Remembers Wh and Ah when power is off

  • Voltage display is within 0.03 volt in the 4.0 to 6.0 volt range.

  • Current display is within 0.02 ampere in the 0 to 3.0 ampere range with 5 volt supply.

  • Over current turn off is at 5A (Can be configured)

  • Over voltage turn off at 30 volt (Can be configured)

  • Under voltage turn off is at 3V, actually 2.3V due to ADC error at low voltage (Can be configured)

  • USB data works fine.

  • Meter has a buzzer that sounds when voltage is connected/disconnected.





M1: 43,9°C, M2: 51,9°C, M3: 49,2°C, HS1: 57,0°C




M1: 49,2°C, M2: 46,6°C, HS1: 61,1°C



Conclusion

This is useful as test equipment, but do not use it between a charger and a phone or pad, it will probably burn the phone/pad.
Together with an external load it can be used to test different types of fast chargers including power banks, but it cannot be used for much else.



Notes

How do I make the test

“This is useful as test equipment, but do not use it between a charger and a phone or pad, it will probably burn the phone/pad.”

Could you or someone explain why this would be true? Thank you!

On a quick charge or a pump express charge any press on the button will increase the voltage above 5V, that is not really good for a phone/pad, except if they are designed for it and expect it.

Thank you! This tool is not for a novice. :slight_smile:

Internal resistance looks disappointing.

For its intended use the internal resistance is not very important. If you want really precise voltage measurement with an external load I would open it up and solder voltage sense wires to the usb input connector.
The internal voltage readout is fairly good.

It seems that there are multiple variants of this device, and they aren’t necessarily well labeled and described by sellers.

As near as I can tell, besides the device HJK reviewed, there are similar devices that lack the triggering functionality

Of these, there are some that report voltage and current to 3 digits, and then others that report to 5 digits. For each of these types, their are LCD and OLED variants.

I have more reviews on the way.

Seems they’re all made by one company, and sold under many names. I have the same (exterior looking) one as HKJ, a brandless J7-t from a different AliExpress seller. It behaves differently than what you describe above. I can’t get it to trigger QC. A long press just resets the readings, and a lot of presses gets me into some sort of timing menu. Also, the display is entirely different as your pictures. The button basically switches between three pages of measurements. It’s the one you’ve reviewed after this one :slight_smile:

I also have a J7-i, from Banggood, branded Juwei (which has some nice contervers and gear for testing, btw) which basically ‘converts’ a normal 5V/USB to a 9V (or 12V) QC output.

Ordered both out of curiosity, and made a video about the QC enabler :

I have that one on order.

Thanks for the review. I’ve bought this adapter from banggood but didn’t arrive yet. Can I use this adapter to fast charge a LG G6 connecting to the USB port of my notebook?

Note that the USB port can provide high current, but when connecting the phone directly to it, the phone only charges at 400mA. I want to trick the phone into thinking that is connected to the wall.

No. Never use this to fast charge anything, at best it will do nothing, at worst it will destroy the phone.

I’ve had similar problems, so I’m planning to buy a couple of these:

https://www.amazon.co.uk/PortaPow-Charge-Block-Adapter-SmartCharge/dp/B00T0DW3F8

I can’t vouch for them yet, because I haven’t actually bought and tested them, but I thought I’d post the link anyway in case it turns out to be useful.

WARNING: you must ensure that the USB power source can provide enough power to charge your device at full current, because the adaptor can’t check that for you. This is especially important with computer USB ports, many of which will only support 0.5A or 0.9A. They should shut down if overloaded, but there’s always the chance that your particular one won’t, and then it will fry instead.

Additional note: this type of adaptor only helps if you don’t want to synchronise data with your computer at the same time, because it has to take over the data connections to implement the charging protocol.

I’ve found this trigger great for powering 12 volt stuff from a QC powerbank without an actual DC plug output.

No problem, I’ve tested my MSI notebook and can charge the Aukey powerbank at a constant rate over 2 amps with the USB voltage dropping to 4.9V or so. Modern smartphones suck up to 1.7~1.8 amps so fair enough, another thing would be a tablet I guess.

When you actually test it and can confirm it works please tell us I would like to buy it too.

What do you think about this one, should work too to trick the smartphone into fast charging? Has a built-in meter and everything:
https://www.amazon.co.uk/PortaPow-Monitor-SmartCharge-Chargers-Panels/dp/B01CVMAK2M/

Sorry, it’ll be a while before I buy them. Too many higher priority items in the queue at the moment…