LDNIO DL-AC52 Dual usb 2.4A



Official specifications:

• Input: 100-240V AC,50/60Hz
• Output: DC 5V 2.4A
• Weight: 50g
• Compatible: USB 2.0 Power Plug.

I bought it from banggood.com, this is not a super cheap model, but cost a bit more. Is this enough to make it safe?



This charger arrived in a retail package.









The two ports are marked "For iOS" and "For android" with some small and nearly invisible letters



Measurements

• Power consumption when unloaded: 0.16 Watt
• iOS output is coded as Apple 2.5A
• Android output is coded as usb charger (DCP).
• USB connectors has a hidden blue led between them.
• Outputs are in parallel.

The two ports are the sam and have very stable output voltage and the efficiency is around 80%, the charger has overload protection at 2.5A. This looks good.



One hour with 2.4A load is not problem.
The temperature photos below are taken between 30 minutes and 60 minutes into the 1 hour test.



M1: 51,4°C, M2: 51,3°C, HS1: 64,7°C
HS1 is probably the rectifier diode on the heatsink.



M1: 52,6°C, M2: 43,6°C, HS1: 70,9°C
HS1 is probably the transformer.



M1: 52,4°C, M2: 42,5°C, M3: 32,4°C, HS1: 69,6°C
HS1 is probably the transformer.



M1: 62,5°C, HS1: 72,7°C



M1: 49,2°C, HS1: 54,9°C




There is some noise at 0.5A with 23mV rms and 520mVpp.



It increases with load, 45mV rms and 700mVpp at 1A.



The peak has increased even more, 38mV rms and 810mVpp at 2.5A.



Tear down



Some pressure on the golden band and I could break it open.



It looks very compact, but it do have a couple of good details: There is a fuse, the switcher transistor is fairly large and the rectifier has a heatsink.



Here the rectifier heatsink can be seen, it is a piece of circuit board. Between the two usb connectors the blue led can be seen.
The capacitor marked Y1 is the safety capacitor.



The safety capacitor is easier to see here and the 105°C capacitors. At the mains input the fuse can be seen (F1).



On the bottom is the bridge recitifer and the mains switcher controller IC (U1).
This model does not use opto feedback, but as can be seen on the load sweep it does fine without.



The safety is always interesting with a compact construction. When using slots in the circuit board the distance for air can be used, i.e. 4 mm, but here there is only 3mm. There is a couple of other places where there also might be problems.



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



Conclusion

There performance of this usb power supply is good and the safety is much better than the cheaps ones, but not good enough.



Notes


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