I currently have a Raspberry Pi 2 B that I am trying to run off of a 2.5A 5V powered USB hub, while also having my peripherals off of that hub. I have the output of the hub to the regular Pi USB slot, and one of the inputs of the hub to the micro-USB power of the Pi. The problem is, the Pi will startup and lights will turn on for about 3 seconds before it shuts down, and starts all over again. I even went so far to snip the two data lines of the USB from the hub to power on the Pi, as well as ground, just in case of a grounding loop. Even with that, it does the same thing. If I don't have the hub output connected to the Pi USB, but still have the hub to the micro-USB power connected, it works just fine, but the moment I plug the hub output into the Pi, it shuts down. Does anyone have a solution for this? I have checked other topics, but nothing really covers what exactly is happening here. I am running OSMC if that matters.
I had this exact problem a while ago. Turned out it was a faulty $1 micro USB power cable. The cable does work fine for charging and syncing a handphone, but for some reason it doesn't supply enough juice to the raspberry. Other cables - the $2 ones - mostly don't give me any issues.
- This just came up in my mind: You tried to cut the data cables out of your link between the hub and pi-powerconnector. How about cutting the power between the pi-usb and the hub? Just an idea but maybe worth a shot.
There are some USB hubs with active power management that when they are plugged into a computer try to negotiate power consumption with every device, so they cut out the power to every device to start plugin events. These hubs (which are otherwise very nice hubs and work fine for every other use) will not work to power the RPI and act as a hub for it at the same time. the two workarounds are to add a really big capacitor (or battery) to the RPI so that it will function through this power interruption, or to steel power from the hub's power supply instead of the hub. It would probably be easier to just use a cheaper hub.