USB power for RPi4

Installing and Using OpenWrt
1

I want to connect a Raspberry Pi 4 to my Belkin RT3200 and use the USB 2.0 port for power. The RPi4 has a USB-C port for power and requires 5V DC (minimum 3A+). I don't see any specs for my Belkin RT3200 router. Nominally, USB 2.0 provides a minimum of 5V and up to 500mA (2.5W), which is not enough. I tried using lsusb to inspect what Linux thinks the port is capable of:

# lsusb -v | grep -E 'Bus|MaxPower'
Bus 002 Device 001: ID 1d6b:0003 Linux 5.15.167 xhci-hcd xHCI Host Controller
    MaxPower                0mA
Bus 001 Device 001: ID 1d6b:0002 Linux 5.15.167 xhci-hcd xHCI Host Controller
    MaxPower                0mA

but that isn't helpful. Is this possible? Is there any other way to discover what the port is capable of? I haven't purchased the RPi4 yet, so I can't just plug it in.

2

I highly doubt a router port will provide enough power for the stable operation of Pi 4. A Pi Zero 1/2 should be fine on the other hand.

1 Like
3

A router's USB-A port will absolutely not have sufficient current capacity to power a Rasperry Pi 4. As you indicated, the Pi4 requires 5V @ 3A (15W). Some USB-A ports can deliver as much as 2.1A (12W), but that typically only true on full computers (laptops/desktops or actual USB power banks/bricks). You won't get anywhere near that from your router. Especially when you consider that the power supply that comes with your router is 12V @ 2A (24W). There is almost no possibility of the system reserving half of the rated supply voltage for USB.

4

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