How are you checking for “Low voltage detected”?
I have a 1.5A 5V power supply connected, but it seems that I keep getting the “Low voltage detected” alert.
My power supply is using a standard Barrel DC power connector and two USB cables are soldered to the connector - one going to the RPi and the other to the HDMI interface/screen.
The whole system draws max 600mA of power - so there is plenty of power left in the supply.
The voltage detection uses the built-in mechanisms for that. It basically calls
vcgencmd get_throttled
and checks if bit 16 is set in the result. According to the documentation
under-voltage occurs when voltage drops below 4.63V.
Did you set the cpu governor to anything other than powersafe [1]? Generally on a Pi3, a 2.5A power supply is recommended. See https://www.raspberrypi.org/documentation/faqs/#power
[1] I just realized the linked documentation is wrong: powersafe is the default. This will be updated soon.
I have now connected the device with a HY3003 Gigimess power supply (3A max) - and I still have the problem.
[edit:] I suspect that it might have something with the splitting to do. I have another device on its own power without problems.
Found the sollution: The used USB cable cannot provide enough power - so changing the wires to a thicker cable did solve the problem!
(PS: This is apparently my new account as LBWA account is closed)