Just a quick update.
I rebuilt my RPi2 image and decided to start a program manually.
The first zone started up immediately, but at that exact moment the web interface was lost. Attempts to reconnect resulted in a ‘connection refused’ browser message. I was still able to ping the pi, and also shell into it.
I let it run past the scheduled duration, and it didn’t stop automatically. I ended up power cycling it to stop the current watering job.
Upon reboot I decided to run another zone, but did so via the home page, and not via a ‘manual program’.
During that job the browser stayed up, but reported a network error. Pings to the unit failed. That job continued to run past its scheduled duration. Power cycled the unit.
I decided to try using a powered USB hub with my USB wifi. I’m using aEdimax EW-7811.
The next manually started zone ran to scheduled completion, and the browser/network remained up throughout.
Following that, I started my last zone and everything worked as expected as well.
I’m going to go back to an older RPi model this weekend and give that a go. Living in Southern California and with all the visibility about watering lawns, I really need to be able to trust my sprinkler timer. And I don’t want to dedicate a powered USB hub, if it turns out the RPi2 is just too power hungry.
How much current is supplied to the RPi during a sprinkler job?