40W 5V/8A 5-Port Family-Sized Wall Charger

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Official specifications

I bought this from ebay dealer ec-sell1

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Measurements


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Output voltage is stable and the efficiency is around 80%, all the usb outputs looks the same, but I am missing overload protection on each port (It do exist, but triggers at a higher current).

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Running all outputs in parallel I can test the full current of the power supply, without to much loss in the cables.
It looks very nice with overload protection kicking in at 8.5A.
In the tear down it can be seen that there is a small fuse for each output, but it does obvious not blow at the currents I used for testing.

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One hour with 8A load is not a problem.
The temperature photos below are taken between 30 minutes and 60 minutes into the 1 hour test.

Temp1783

M1: 57,8C, M2: 62,3C, M3: 61,4C, HS1: 73,8C
Generally the box get fairly warm, this is unavoidable with the amount of power it handles and the compact size.
The hottest spot here is the two rectifier diodes (HS1), the heatsink for the diodes (M2), the transformer and the heatsink for the main switcher transistor (M3).

Temp1784

M1: 58,3C, M2: 57,7C, M3: 59,6C, HS1: 76,0C
Again the heatsink for the rectifier diodes can be seen (M1)

Temp1785

M1: 58,0C, M2: 46,7C, M3: 58,6C, HS1: 66,8C
The circuit board is warm below the heatsink for the rectifier diodes, especially where the diodes are mounted (HS1)

Temp1786

M1: 64,2C, M2: 45,7C, M3: 53,9C, M4: 51,4C, HS1: 65,6C
The heatsink on the rectifier diodes does also warm this side of the box (HS1), the transformer (M3) do also add a some heat.

10ohm

The rms noise is low, but there is some spikes: 15mV rms and 440mVpp at 0.5A.

2.5ohm

At 2A the noise is 24mV rms and 700mVpp

1.2ohm

At 4A the noise is 24mV rms and 630mVpp

0.6ohm

At full power (8A) the noise is up to 45mV rms and 1200mVpp



Tear down

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The box was closed very well, I had to cut it open (Very good).

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Due to the heatsink it can be difficult to see some of the parts. I found a fuse, common mode inductor, bridge rectifier, mains switcher transistor, opto feedback, safety capacitor, two rectifier diodes.

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On the bottom is the mains switcher chip (A small 6 pin IC marked U1). The F2 to F6 is small fuses protecting the outputs The chips U5 to U9 is the automatic usb coding..

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There is a good distance between mains and low volt side on the circuit board.


Testing the mains input with 2500 volt and 5000 volt between mains and low volt side, did not show any safety problems.



Conclusion

This power supply/charger looks acceptable, it has lots of power, good isolation between mains and low volt side, stable output voltage and can charge just about anything, only "problem" is the spikes in the output voltage. This may make some equipment malfunction.



Notes

Index of all tested USB power supplies/chargers
Read more about how I test USB power supplies/charger