Test/review of Rock QC 3.0 30W 3 USB charger

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HKJ
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Location: Copenhagen, Denmark
Test/review of Rock QC 3.0 30W 3 USB charger

Rock QC 3.0 30W 3 USB charger
DSC_8202
Official specifications:


  • Input: 100-240V 50/60Hz 0.35A
  • Max Power: 30W
  • Output (QC): 5V/3A, 9V/2A, 12V/1.6A
  • Output (USB): 5V/2A
  • Material: PC fireproof Material
  • Size: 25 * 45 * 52mm

I got it from Aliexpress dealer: ROCK Official Store
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Measurements


  • Power consumption when idle is 0.4 Watt
  • Minimum QC3 voltage is 3.6V
  • Voltmeter can only show 5.0, 9.0 and 12.0V and do not show actual QC3 voltage.
  • All USB outputs has a common minus connection
  • The two standard USB outputs are coded as USB charger (DCP)
  • Q3 output is coded as Apple 2.4A, Samsung, DCP, QC3
  • Weight: 54.8g
  • Size: 89.4 × 45.3 × 26.6mm

current
The ammeter is moderately precise, but a bit optimistic. It shows the current for the QC output. The voltmeter do not show the actual voltage.
Rock%20QC%203.0%2030W%203%20USB%20charger%20%231%20230V%20load%20sweep
The top USB output can only deliver about 1.1A.
Rock%20QC%203.0%2030W%203%20USB%20charger%20%232%20230V%20load%20sweep
The same with the second USB output.
Rock%20QC%203.0%2030W%203%20USB%20charger%20%2312%20230V%20load%20sweep
Can they reach the rated 2A when working together? No, it is still 1.1A
Rock%20QC%203.0%2030W%203%20USB%20charger%20%231%20120V%20load%20sweep
The output is the same at 120VAC
Rock%20QC%203.0%2030W%203%20USB%20charger%20QC5V%20230V%20load%20sweep
The QC output is rated for 3A, but cannot deliver more than 2.3A
Rock%20QC%203.0%2030W%203%20USB%20charger%20QC9V%20230V%20load%20sweep
The current is nearly the same at 9V
Rock%20QC%203.0%2030W%203%20USB%20charger%20QC12V%20230V%20load%20sweep
At 12V the maximum current is dropped to 1.8A, this fits with the 1.6A rating.
Rock%20QC%203.0%2030W%203%20USB%20charger%20QC12V%20120V%20load%20sweep
At 120VAC the maximum current at 12V is slightly above 1.6A
Rock%20QC%203.0%2030W%203%20USB%20charger%201A%2B1.5A%20230V%20load%20test
First I tried with 1A on USB and 1.5A load on QC, it only worked for about 22 minutes, then the QC output failed.
Rock%20QC%203.0%2030W%203%20USB%20charger%201A%2B1A%20230V%20load%20test
Reducing the QC current to 1A and trying again worked better.
The temperature photos below are taken between 30 minutes and 60 minutes into the one hour test.
Temp7003
HS1: 97.0°C
At 1A+1.5A the charger got very hot. HS1 is the QC transformer.
Temp7008
M1: 82.9°C, HS1: 86.3°C
HS1 is the QC transformer and M1 is the USB transformer.
Temp7009
HS1: 75.1°C
HS1 is the QC switcher.
Temp7010
HS1: 67.3°C
HS1 is the QC transformer.
Temp7011
HS1: 72.7°C
Temp7012
M1: 51.4°C, HS1: 85.1°C
10ohm
At 0.5A the noise is 112mV rms and 726mVpp.
5ohm
At 1A the noise is 138mV rms and 372mVpp.
10ohmQC5V
At 0.5A the noise is 29mV rms and 723mVpp.
5ohmQC5V
At 1A the noise is 40mV rms and 1015mVpp.
2ohmQC5V
At 2A the noise is 12mV rms and 282mVpp.
10ohmQC9V
At 9V 0.9A the noise is 52mV rms and 1138mVpp.
10ohmQC12V
At 12V 1.2A the noise is 68mV rms and 1050mVpp.
Tear down
DSC_9245
This type of charger is easy to open. Mount the base in my vice and give the top a whack with a mallet.
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The charger is two partly separate switchers, they share the input fusible resistor (F1) and the two smoothing capacitors (EC1 & EC2).
The QC output has the switcher (U1) and opto feedback (U2) on this side of the circuit board and uses the red transformer (T2). The normal USB output uses the smaller white transformer (T1). The safety capacitor (CY1) is placed beside that transformer. On the output side is the smoothing capacitors (EC5 & EC6), the meter and the USB connectors.
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This side has the bridge rectifier (BD1), the USB switcher (U5) and rectifier diodes for QC (D2) and USB (D3). The QC controller (U4: LP103S). The current sense resistor for the meter is here (R1: 0.025ohm)
There is some bad soldering/placement here (C4) and some solder balls (R4 and many other places).
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The meter module is very compact with a microprocessor/voltmeter chip and a regulator (U2: HT50, probably 5V).
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On this side is the display and a few resistors.
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The distance between mains and low volt side is supposed to be above 6mm, here it is below 2mm.
The charger passed the 2830 volt test, but failed the 4242 volt test between mains and low volt side, this makes it unsafe for 230VAC countries.
Conclusion
This charger has low production quality, is way below specifications and is unsafe.
Notes
The charger was supplied by a reader for review.
Index of all tested USB power supplies/chargers
Read more about how I test USB power supplies/charger
How does a usb charger work?

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

s5610
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“Gnome” transformer, DIP8 PWM, 817 optocoupler – did you see such power supply? You saw them all )

HKJ, you can pass by with tests on trashy looking interior, we will understand you. Save the time Big Smile

HKJ
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Last seen: 5 hours 18 min ago
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Location: Copenhagen, Denmark

s5610 wrote:
“Gnome” transformer, DIP8 PWM, 817 optocoupler – did you see such power supply? You saw them all )

HKJ, you can pass by with tests on trashy looking interior, we will understand you. Save the time Big Smile

Sorry, I am not sure what you mean.
I do not know how a charger looks inside before testing it, opening the charger is first done when I am done with all my tests.

I do believe testing bad chargers is important, how can you know it is a bad charge without testing it? I will admit that it is fairly easy to guess in some cases, but some of my guesses have been wrong!

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

s5610
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Last seen: 1 week 1 day ago
Joined: 08/19/2018 - 18:25
Posts: 17
Location: Moldova

HKJ wrote:

I do not know how a charger looks inside before testing it, opening the charger is first done when I am done with all my tests.

Would it be vice versa, first disassemble then testing, could potentially save time. E.g. when we see 1 mm gap between mains and secondary circuit, is it worth to test further… I’m sure after hundreds of reviews you can predict the result roughly at a glance on what components are used. But sure it wouldn’t be so excite when you test “a black box”, and, what is more important, your project is about testing, not choosing+buying. It’s educational thing.

P.S. Can you give a hint, when you were wrong? A bad looking PSU, but good results.

HKJ
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Last seen: 5 hours 18 min ago
Joined: 05/24/2011 - 12:23
Posts: 6806
Location: Copenhagen, Denmark
s5610 wrote:
Would it be vice versa, first disassemble then testing, could potentially save time. E.g. when we see 1 mm gap between mains and secondary circuit, is it worth to test further…

I sometimes damages a charger when opening it, so I have to test first.
I do also believe it is interesting to see how bad the bad chargers are.

s5610 wrote:
P.S. Can you give a hint, when you were wrong? A bad looking PSU, but good results.

Yes, it sometimes happens a cheap charger passes all tests.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/