Test/review of Dual USB Wall charger Keke-F5

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HKJ
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Test/review of Dual USB Wall charger Keke-F5

Dual USB Wall charger Keke-F5
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Official specifications:


  • Input: 120-240V AC
  • Output: 5V 2.1A

I got it from ebay dealer ddarlingshop
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It was packed in a plastic bag inside the usual envelope.
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Behind the two green teardrops (one on each side) is a led.
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Measurements


  • Power consumption when idle is 0.15 watt
  • One USB output code with Samsung.
  • The other usb output is usb charger (DCP).
  • The two outputs are in parallel.
  • Weight: 27.4g
  • Size: 78 × 36.7 × 24.7mm

Dual%20USB%20Wall%20charger%20Keke-F5%20%231%20230V%20load%20sweep
The charger can deliver 1A, not the rated 2.1A
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It is the same on the other port.
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And when using the ports in parallel.
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Using 120VAC gives the same result.
Dual%20USB%20Wall%20charger%20Keke-F5%20230V%20load%20test
Running 1 hour at 1A worked fine.
The temperature photos below are taken between 30 minutes and 60 minutes into the one hour test.
Temp5882
M1: 56.8°C, HS1: 58.7°C
HS1 is the transformer and M1 is the rectifier diode.
Temp5883
M1: 44.1°C, HS1: 53.3°C
Temp5884
HS1: 44.1°C
Temp5885
M1: 53.3°C, HS1: 57.0°C
10ohm
At 0.5A the noise is 97mV rms and 688mVpp.
5ohm
At 1A the noise is 114mV rms and 635mVpp.
Tear down
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Placing the charger in my vice and whacking one with my mallet did open it.
The green teardrops was not glued and if they fall out the charger is very dangerous to touch.
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On this side is the input fuse (RF1: Fusible resistor), a bridge rectifier, the two leds and a large rectifier diode.
The “blue safety capacitor” is not a safety capacitor, but just a 1000V capacitor.
It is interesting to see the circuit board is marked 1A, this matches the output of the charger, but not the external marking.
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On this side it the mains switcher.
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Creepage distance is about 2mm, this is way to short.
Testing with 2830 volt and 4242 volt failed the 4242V test, this means it is unsafe in 230V countries.
Conclusion
The charger is a 1A charger with a lot of noise.
Too short distance between mains and usb, together with a unsafe capacitor, this rather bad safety.
Stay away from this charger.
Notes
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/