Comment 7 for bug 378221

Rick re: "we should try to do things differently when on battery than when on Mains".

If I'm living on a boat, my "mains" is just a bunch more batteries (admittedly bigger ones); if the wind hasn't blown, or the sun hasn't shone, there might not be very much of it! ...If it's possible to avoid doing something on battery in order to save power, it's probably possible to avoid doing it on mains too! (Which saves energy, reduces heat output and allows more power to be diverted to recharging the laptop's internal batteries).