Lidu Dual USB Power Adapter / Travel Charger

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Official specifications:
I got this charger from fasttech

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I got this charger in a retail plastic box.

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Measurements

Lidu%20Dual%20USB%20top%20load%20sweep
Lidu%20Dual%20USB%20bottom%20load%20sweep

Top and bottom output looks the same, i.e. they are in parallel. About 2.1A the output voltage will start to drop and at about 2.4A the over load protection kicks in. This is a good behaviour.

Lidu%20Dual%20USB%202.1A%20load%20test

Running a load test at 2.1A did not work, the charger shut down after 16 minutes. It is nice that it can shut down when over heated, but I would have liked to get the rated current from it.

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Reducing to 1.8A improved it a bit, now I could run for 43 miutes before it shuts down.

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At 1.6A it works perfectly
The temperature photos below are taken between 30 minutes and 60 minutes into the 1.6A one hour test.

Temp1668

M1: 44,9C, M2: 35,7C, M3: 43,1C, HS1: 61,0C
It is not that hot.

Temp1669

M1: 43,6C, M2: 38,9C, HS1: 53,1C


Temp1670

M1: 45,9C, HS1: 58,4C


Temp1671

M1: 37,4C, HS1: 42,8C


Temp1673

M1: 32,6C, HS1: 45,6C


2.5ohm

The noise is fairly low at 2A with 82mV rms and 340mVpp.

10ohm

With lower load the noise decreases: 42mV rms and 260mVpp



Tear down

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Some pressure on the box and it pops open.

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This circuit has a real fuse, a bridge rectifier, a inductor (L1), but the Y capacitor (Y1) is not a approved model, it is a 1000 volt regular capacitor.

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On the bottom of the circuit board is a switcher IC to control the charger, including heat shutdown.
The big rectangular device below the trafo is a diode and it looks like this is the major heat source.
The soldering do not look very good

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This charger has some isolation distance, but not enough.


The charger failed a isolation test with 2500 volt, this makes it doubtful to use with 120VAC mains, not the best situation for a charger with 230VAC plug.



Conclusion

The performance of this charger is acceptable, but the safety is not.

Stay away from this one!



Notes

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