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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.

Tomas By
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3 Answers3

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Either the power supply OR the cable is inadequate. (I make my own cables, because there is no source of adequate cables.)

See Raspberry Pi Power Limitations

Milliways
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The warning is telling you the power supply is insufficient, in particular it is dropping below 4.65V under load.

joan
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The power is insufficient in the respect the power supply cannot supply enough current

I've had this issue running just a Pi 3 from a 1.8A 5V USB adapter. A 2.5A solved the issue for me. Look for higher current, NOT higher voltage*.

With regards to measuring with the voltmeter, it may be difficult to see the spikes that cause the symbol to appear, most likely when under load. You can try measuring how much current draw the Pi is using (perhaps compare this with and without the touchscreen) to see how much extra the screen uses, though a quick look at retailers suggest supplys that can do 2.4A may be enough - so a 3A supply should work...

*A slightly higher voltage (e.g. 5.1 on some semi-official adapters) will help with voltage drop over the cable length etc

Wilf
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