I ran an endurance test with MaLPi (see https://plus.google.com/u/0/102063919580003650665/posts/Av6RVgunSQ8
), running the Pi, the webcam and a shell script that logged uptime every ten seconds and the motion program (/usr/bin/motion) in an attempt to detect changes in the battery's status indicator LED's. That last part failed, but according to the log it ran for ten hours and fifteen minutes. The average cpu load was pretty low, at 0.06.
I had asked PowerGen if it was safe to have their battery being charged at the same time it was being used to power my Raspberry Pi and they got back to me and said that was safe, so I can leave the battery plugged in if I want leave MaLPi running unattended, while still being able to unplug it for mobility.
Next step is to figure out how to mount it all on my rover body. I think I'll leave out the USB hub until I actually need it. My one attempt to power both the Pi and the hub from the battery didn't work out so well. The Pi kept crashing.