Test/review of Nokoko 4 port usb charger

HKJ · 2018-11-03T16:01:12.000Z

Nokoko 4 port usb charger

Official specifications:

Input Voltage: AC 100-240V
Input Frequency Range: 50-60Hz
Output Voltage: 5V / 5.1A Max (2.1A + 1A + 1A + 1A)
ork Efficiency: 85–95
Working Temperature:0°C ~ +50°C
Storage Temperature: –20°C ~ +85°C.
Color: Red,Gold,Blue,Silver
Plug Type: US plug/EUplug
Size: 3.7*3.4*8cm / 1.5*1.3*3.1” (L*W*H)

I got it from Ebay dealer: purchase365

It arrive in a plastic bag inside an envelope.

Lot of markings on the front, but all outputs are exactly the same.

Measurements

Power consumption when idle is 0.15 watt
There is a two blue leds behind the usb connectors.
All usb outputs are coded with usb charger (DCP)
All usb outputs are in parallel.
Weight: 39.4g
Size: 79.4 x 37.4 x 33.7mm.

The output on a port is 2.3A

Another port is the same.

All ports in parallel is also 2.3A, not the rated 5.1A

Using 120VAC do not change much.

I did the load test at 2.2A and the charger could sustain that for one hour.
The temperature photos below are taken between 30 minutes and 60 minutes into the one hour test.

M1: 67.1°C, HS1: 68.9°C
HS1: The main heat producer is the transformer

M1: 51.7°C, M2: 42.9°C, HS1: 57.9°C

HS1: 48.8°C

HS1: 68.1°C

M1: 60.9°C, HS1: 67.1°C

Noise at 0.5A load is: 77mV rms and 1488mVpp.

Noise at 1A load is: 129mV rms and 2020mVpp.

Noise at 2A load is: 146mV rms and 2144mVpp, the noise is very bad.

Tear down

Mounting it in my vice and whacking it with my mallet popped the lid off.

On this side is a fuse (F1), the safety capacitor (CY6) and the two leds (LED1 & LED2).
The usb connectors is mounted on a separate circuit board that only contains the connectors, nothing else (DCP coding do not required any components).

On the mains input side is a bridge rectifier (BD1) and the mains switcher (U1: Marked HC2523E), on the low volt side is a synchronous rectifier chip (U2: Marked HC3520).

The distance between mains and low volt side is about 2mm, except at the end of the slot where it is less, this is way to low.

It failed both the 2830 volt and 4242 volt between mains and low volt side, this makes it unsafe to use anywhere in the world.

Conclusion

Way less current than specified and lots of noise, in addition to poor isolation.

Stay away from this one.

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?

duramax · 2018-11-03T16:28:08.000Z

thank you for the review, very helpful.