The batteries that I use are Rayovac Renewals. These are rechargable
alkalines. I get about 3-4 hours (using battery watcher) off of them when
they are new (the more they are recharged the less time you get). I carry a
spare set with me and switch them when they get low. I also carry a pocket
charger (it is a little to big to be put in the pocket, but still quite small)
and charge the set after they are removed. I go through a four pack of
batteries (2 sets of 2 batteries) every 2 months. The chager cost me $10 and
the batteries are only $5 for 4. These have more than paid for themselves (in
both money and garbage collected). I have also found that even though the
batteries may not be able to hold a good enough charge to run the omnigo they
still work well in other things (remotes, pocket radio). This way I get even
more use out of a set.
Enjoy,
Marty