Anker Power Port 6 (60W)
Powering up multiple Raspberry Pi will be messy if you use separate power adapters for each RPi. Anker Power Port multi USB comes in handy to deal with Raspberry Pi cluster projects in a neat way. Each port can give upto 2.4Amp and in total 60W for all the ports put together at any given point of time.
Typically Raspberry Pi bare-board (without additional USB attached peripherals) will take maximum of 600ma even the latest Raspberry Pi 4. Check the official link from Raspberry Pi foundation
https://www.raspberrypi.org/documentation/hardware/raspberrypi/power/README.md
It is required to use 3Amp rated power adapter for Raspberry Pi 4, only if you are drawing current from other peripherals attached to USB or GPIO.
Usually in Raspberry Pi cluster projects, there won't be any peripherals attached Raspberry Pi other than USB Keyboard/Mouse. Hence, the Anker Power Port can be used to power 6 Raspberry Pi's at once safely.
