Nexus 5X - Why charging still drains battery?

[AC Question]

I bought a USB cable for it (USB to USB type C), and I charge it via a charger that's at the office (which works fine with older devices) .
For some reason, even while it charges, it drains battery, so much that by the end of the day, it can get to 0%.

Looking at the Ampere value (using an app "Ampere") , it seems very low (around 300mA) .

I even tried to use a Samsung charger (which was used for SGS4) . About the same Ampere value.

How could it be?

 

[the tall guy]

So when you charge the device, is it actually connecting to your device, can you see it charging? have you tried charging the device on a different outlet, like at home?

 

[AlphaTango414]

Try a different usb cable with it. What made you get a usb to type c cable for?