30W USB Desktop Charger

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Official specifications:
I got this charger from ebay dealer: bg27cyf

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I got this charger in a retail box.

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Measurements


30W%20USB%20Desktop%20Charger%20%236%20load%20sweep
30W%20USB%20Desktop%20Charger%20Right%20load%20sweep

Doing a single port or a full column at a time gives the same result. The right outputs can deliver slight above 3A before they shuts down, this is good.

30W%20USB%20Desktop%20Charger%20Left%20load%20sweep

The left columns can deliver considerable more current before they shuts down, i.e. there are fairly large tolerance on the current limiters.

30W%20USB%20Desktop%20Charger%203A%20Right%20load%20test

Trying to run the right column at 3A for an hour did not succeed, it closed down within 8 minutes.

30W%20USB%20Desktop%20Charger%202.5A%20Right%20load%20test

Reducing the load to 2.5A worked better, but not perfect.

30W%20USB%20Desktop%20Charger%202A%20Right%20load%20test

At 2A it did not have any problems.

30W%20USB%20Desktop%20Charger%202.5A%20Left%20load%20test

Running the left column at 2.5A worked fine.


The temperature photos below are taken between 30 minutes and 60 minutes into the one hour test.



2.5A on left column

Temp1727

M1: 56,2C, M2: 53,0C, HS1: 74,4C

Temp1728

M1: 69,6C, HS1: 74,5C

Temp1729

M1: 43,2C, HS1: 71,5C
Here it is obvious that the heat is only for one side of the charger.


Temp1730

M1: 39,0C, HS1: 56,5C



2.5A on right column

Temp1723

M1: 50,7C, HS1: 52,9C

Temp1724

M1: 53,9C, HS1: 82,5C

Temp1725

M1: 51,7C, M2: 51,9C, HS1: 77,4C

Temp1726

M1: 56,0C, HS1: 74,1C




2A on right column

Temp1719

M1: 46,3C, HS1: 47,5C

Temp1720

M1: 44,3C, HS1: 69,2C

Temp1721

M1: 48,9C, HS1: 63,2C

Temp1722

M1: 45,7C, HS1: 59,2C


0.8ohm

With both channels and a 6A load the noise is 74mVrms and 750mVpp

2.5ohm

Reducing the load to 2A reduces the rms noise 48mV rms and 700mVpp.

10ohm

With 0.5A load the peak noise increases: 42mV rms and 1000mVpp



Tear down

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When opened it is obvious that the charger has two separate channels. There are two mains switchers, two transformers and two low voltage circuit.
The input has a fuse.

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Here the bridge rectifier can be seen.

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The isolation distance between mains and low voltage side is about 1 mm and there is a non-safety capacitor across (Very bad).


The charger passed 2500 volt test, but failed a isolation test with 5000 volt, this makes it doubtful to use with 230VAC mains. When the test failed there was a short between mains and low volt side (Very bad)



Conclusion

The charger is rated for 3A+3A output on the bottom, this is a bit optimistic and also means that it can only charge two devices at full 2A current simultaneous (On in left and on in right column), the full 6A cannot be used.

The safety is bad, stay away from this one.


Notes

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