2.1A Dual USB car charger



Official specifications:

• Input Voltage: DC12V-24V
• Output Voltage: 5V
• Output Current: 2.1A/1A
• Material: Aluminum Alloy.
• Size: 6x6x2.5cm.

I got it from Aliexpress dealer: Maintain_Your_Car Store



It arrived in a plastic bag inside a envelope, no instruction sheet included.











Measurements

• USB outputs are coded as usb charger (DCP)
• USB outputs are in parallel.
• There is blue light inside the charger.
• Weight: 19.2g
• Length: 68mm
• Diameter: 25.7mm

For a 2.1A rated output it is rather weak with overload limit at 0.9A



Slightly higher voltage did not help



With 24V input I got slightly above the 0.9A, but not for long and it did not work after that. This means no more tests.


Tear down



I could remove the front with a spudger and then pull the circuit board out.



The circuit has two capacitors, a rectifier diode, a inductor and a chip (AD85063: 5V 1A)



The reason the circuit stopped working is obvious, the chip could not really deliver the rated current and was low on protection.








There is nothing on the bottom.




Being a 12V device there is no need to test with high voltages.



Conclusion

This charger is over rated and the chip cannot handle overload, this is a rather bad charger.



Notes

Read more about how I test USB power supplies/charger
Compare car chargers and other DC supplied chargers