From what I can tell, powersave mode extends battery life by a lot, almost two fold in my case. I don't really notice much difference when driving down the road, plotting a course or whatnot. If you watch the clock in powersave mode, it doesn't update every second, but sometimes every 5 or 10 seconds.
I always use powersave, unless I'm in a dense area, in which I might be having trouble getting good reception.
I also have a Garmin12. How long do the duracells last four? Also my manual does not have anything on powersave mode. What exactly is it supposed to do? Stuart >I just thought I'd let everyone know of the success I've had with Duracell >Ultra batteries. I have a Garmin 12, and I use it in Power Saving mode. >The set of Duracell Ultras lasted longer than any other battery I've ever >tried in this unit > >Gregg