Depends on the model but some Garmins have long battery life, especially if you switch off the backlight. My Garmin 310xt had plenty of charge left both times I ran Comrades. I had used this battery life to justify its purchase in the first place as my old Garmin would have conked out before half way.
Lowrez the stations have water, Gatorade, cola and some have food - chocolate, biscuits and salty potatoes. Folks on the course will give out stuff. I wear a spibelt and carry only gels as fuel. You don't get given those on the course but there is so much else you don't need to weigh yourself down.
Thanks Lorenzo - but thankfully I'm injury free at the moment.
To answer your earlier question, I have stayed at City Lodge twice. It is not as high class as the Hilton but cheaper, well located and I have no complaints. I am at the Hilton next year as there was a good deal. There are quite a few other places where folks have stayed. There were offers on flights the lady time I looked. Emirates is two quite long flights but goes to Durban direct from Dubai, otherwise it is a very long flight to Joburg and a short flight to Durbs. There is plenty to do if you are able to stay longer than just for Comrades.