Under voltage?

My RPi 3 with OSMC Leia build power supply is a bench supply 5V 6A.

When OSMC automatically upgraded to the nightly this AM It did a lot of under voltage warnings. There is nothing plugged into the USB only wifi and a gpio IR receiver. I had similar results using an ATX power supply 5V 10A.

How is it possible for the Pi to be drawing more than 10A?

It will not draw more than 10A but the Voltage seems to drop below 5V. So suggest to try another cable.

ATX power supplies are sometimes a bit weird that they need certain loading on them to work properly so if you are only using the 5V rail and nothing on 3.3V or 12V then it may not actually provide the current you think it does.

Set the bench supply to 5.2V if possible, should compensate for the voltage drop in the cable and be within the 5% tolerance of 5V.

Cable length and gauge are also important factors to consider. You can calculate the voltage drop here if you know the gauge of the wire.

I believe the official Pi PSU uses 18 awg / 0.82 mm2 cable that’s 1.5m long, so for a 1A load, the supplied 5.1V will still be around 5.04V at the business end.

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Thanks, I have a couple of old 5 gb ide drives in the bin, I will give that a try.

Nope, that didn’t work. The wire is 8 inches long, doubt that is the issue. 1.6 G ide drive attached to both rails and spinning. My VOM says 5.6 V

On normal reboot under voltage when the ethernet adapter gets activated. Nothing plugged into it, using wifi.

The under voltage occurs multiple times when it is upgrading the nightlies.

Never mind, That 5.6 reading was from a different PSU. It was really 4.85. Changed PSU that is putting out 5.06 steady.