Roch T14 3 port Travel Adapter

DSC_5400

Official specifications: I got it from banggood

DSC_5360 DSC_5361 DSC_5362 DSC_5363

I got it in a cardboard box.

DSC_5397

The box included the charger and a warranty card.

DSC_5401 DSC_5405 DSC_5406

DSC_5402

DSC_5403 DSC_5408

DSC_5404 DSC_5407

DSC_6257 DSC_6256

Voltage and current display. Voltage display will only be shown at the start and end, not while it is charging a device.




Measurements

Display

Current display is very precise, but it will drift a bit with temperature (After 15 minutes 3.00 increased to 3.03).

DisplayV

Voltage display is not as good. To get the real voltage I measured voltage on one usb connector and put the load on another usb connector. The result did not change much when I tried different connectors.

Roch%20T14%203%20port%20Travel%20Adapter%20%231%20230V%20load%20sweep

The charger can deliver about 3.25A on output #1, before overload trips.

Roch%20T14%203%20port%20Travel%20Adapter%20%233%20230V%20load%20sweep

The same on output #3

Roch%20T14%203%20port%20Travel%20Adapter%20230V%20load%20sweep

And also with all outputs in parallel.

Roch%20T14%203%20port%20Travel%20Adapter%20120V%20load%20sweep

It is about the same as 120VAC.

Roch%20T14%203%20port%20Travel%20Adapter%20230V%20load%20test

Running one hour at 3A was no problem.
The temperature photos below are taken between 30 minutes and 60 minutes into the one hour test.

Temp4964

M1: 47,8C, M2: 39,5C, HS1: 66,7C
HS1 is the rectifier chip.

Temp4965

M1: 41,4C, HS1: 47,6C

Temp4966

M1: 47,9C, HS1: 55,8C
HS1 is the transformer.

Temp4967

M1: 54,1C, HS1: 57,9C

Temp4968

M1: 45,7C, HS1: 65,4C


10ohm

At 0.5A the noise is 11mV rms and 113mVpp.

5ohm

At 1A the noise is 16mV rms and 113mVpp.

2ohm

At 2.5A the noise is 22mV rms and 111mVpp, this is very low noise numbers.



Tear down

DSC_6258

Some pressure with the vice and a few whacks with my mallet and it was open.
DSC_6261

On this side is a fuse (F1) between the mains input connectors and a inrush current limiter (TH1: NTC). The common mode coil is left out, but there is a inductor (L2) between the two mains capacitors. The safety capacitor (CY1) is close to that.
The auto coding chip (PC5889) is between two usb connectors.

DSC_6264 DSC_6265

The display is on its own circuit board

DSC_6266 DSC_6267

DSC_6273

The voltmeter and ammeter is done by an unmarked chip.

DSC_6262

There is an isolation slot in the circuit board with some black plastic in it, this secures very good isolation distance.

DSC_6271

At the input is a bridge rectifier (DB1) and a SMD inductor (L3) to remove some noise. The switcher controller (U1: Marked AAGE35) is a small chip and it needs a switcher transistor, it is hidden in the white stuff on the other side, but the connections can be seen very close to R15/C9.
On the low volt side is a synchronous rectifier chip (JW7707K). There is two resistors in parallel (R23 & R24 0.1ohm) for measuring the output current (My guess is that the voltage is measured before these resistors and that is the reason for the high readings).

DSC_6268

DSC_6270

The isolation distance is very good.

Testing with 2830 volt and 4242 volt between mains and low volt side, did not show any safety problems.



Conclusion

The charger works fine with low noise, stable output voltage and auto coding (On two connectors) and has a display showing the current with good precision. I did not see any safety problems.
BUT with only 3A for 3 connectors it is very weak, no marking on ports about auto detect or not and the build-in voltmeter is not very precise.

I will rate it as a good charger, but it is best used for one or two devices, not for 3.



Notes

Index of all tested USB power supplies/chargers
Read more about how I test USB power supplies/charger
How does a usb charger work?