« on: June 21, 2011, 01:50:53 PM »
he did raise another question, which in camera terms translates to "do you have a battery grip, or only use one battery at once?"
I think even with a battery grip, the camera only uses one battery at any given time. I do know that when I insert a fully charged and a partially discharged battery into the grip, the camera will drain the fully charged battery to the point where the two batteries are approximately equal, then start alternating between them from shot to shot based on the reported shutter count. I do wonder how it handles operations like Live View or Video, though - does it switch between batteries during the operation, or only at a 'break' (could easily be tested).
That's an interesting behaviour, but certainly understandable (and i should have thought of it already). Keeping the batteries at their highest level (ie, using the higher one before the lower one) is a good move by canon to keep battery life longer.
Electric car batteries connected in series have this thing called 'balancing' they do during charge, they engage resistors to burn off power until they all have the same voltage as the lowest cell. It (apparently) keeps the cells in better condition than if they were all different voltages (it does waste a lot of power though).
in the grip they're definitely not connected in series, that would double the voltage to everything, and i should have realised that they wouldn't be paralleled either without some kind of balancing...
I'd be interested too to see how it works under movie-mode, my guess is that since they say they can measure charge to 1%, as soon as one drops by 1% then it switches to the other (it's not so hard to keep it working during the switch-over)