I usually can go a week or 2 with my cybook reading at least 3 hrs every day. I turn it off when I know I won't be reading again for more than an hour, I have it set to auto turn off after an hour if I misjudge the timing. I usually end up adding a new book at least once a week and let it fully charge at that time, this means I rarely get below 50% available battery.
My Cybook was great for my 7 day camping vacation with no charging options. I arrived with 100% available battery and left with 40% battery available. I read 1.5 books while I was camping and only needed the one eBook reading device.
