Dual 2-port USB car charger UP-158-1
Official specifications:
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Input: DC 12-24V
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Output: DC 5V 3.1A
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Exists in multiple colors
I got it from ebay dealer xinghaishi44
Being from ebay there is not much packing, only the envelope and a plastic bag, there was no accessories or manual included.
The usb connectors and the ring around them will light up with a blue light when the device is powered.
Measurements
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Power consumption when idle is 0.1 watt at 12V and 0.16 watt at 24V
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The two outputs are in parallel.
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No individual port overload protection.
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Usb ports are both coded as usb charger (DCP), the 2.1A and 1.0A labels are meaningless.
The 3A output current specification is wrong, it can only deliver 1.2A and the efficiency is fairly low.
Using 24 volt does not improve anything, here the maximum current is down to 1.1A and the efficiency is even lower.
It can maintain output voltage down to 10V input voltage, this is fine.
With no load it works it works down to 7 volt.
I did only test it with 1A and it could maintain that.
The temperature photos below are taken between 30 minutes and 60 minutes into the one hour test.
M1: 42,7°C, M2: 42,9°C, HS1: 46,3°C
Temperature is acceptable.
I had to use a rubber band to keep it in my test socket.
M1: 44,9°C, M2: 41,2°C, HS1: 46,6°C
At 0.5A with 12V input the noise is 41mV rms and 200mVpp, this is acceptable.
At 1A with 12V input the noise is 44mV rms and 212mVpp.
At 0.5A with 24V input the noise is 170mV rms and 720mVpp, with this higher input voltage the noise on the high side.
At 1A with 24V input the noise is 150mV rms and 700mVpp.
Tear down
I did not know how to open this and cut it open, but I could just have removed the front and it would be open.
The chip used is a LC51, it do not need many support parts: Capacitor on input and output, inductor and rectifier diode.
There is nothing on the other side.
The two usb connectors is on a small circuit board together with two leds and resistors.
Being a 12/24V device there is no need to test with high voltages.
Conclusion
This usb charger works, but with only 1A for two usb connectors it is very weak. The coding of the usb outputs are the same and there is no reason for the 1A/2.1A markings. It is not really good for 24V, due to the noise.
I do not see any reason to buy this car charger, the performance is simply too low for today’s usb equipment.
Notes
Index of all tested USB power supplies/chargers
Read more about how I test USB power supplies/charger