I have a RPi 3 and a 7" touch screen, powered by a MW GS18E05 adapter. It says output 5-6V, 3.0-2.5A, max 15W.
The top right corner yellow flash low power warning shows up when I boot and then it comes and goes when the machine is running. I have some graphical interface, not sure which one. It is a standard Raspbian distribution I believe. I am not doing anything else, no applications running.
Am wondering what this means? Is it normal for the flash icon to appear?
Do I need a better power supply?
Addition: the power is connected to the screen, and then there are cables from it to the GPIO (they came with the screen).
More: am using a short custom made cable from a panel mount barrel type connector to micro usb.
Also: when I measure voltage it says 5.12 on the adapter (not connected to anything) and between 4.96 and 5.02 on the connector with the RPi running. The flash icon comes and goes and is not on for more than a few seconds at a time. I wasn't able to notice any correlation with the voltage fluctuations.