I just got the Oly EP-5 used for about half of retail. Was street shooting from the hip using the touch screen to autofocus and after about ten minutes of shooting the battery went from two bars down to low battery. Hadn't charged it prior to shooting, but has anyone else experienced such a quick depletion from two bars? It would appear to mean two thirds full... Should I get a new battery for this camera to start, and if so, does anyone have an opinion about Olympus versus generic batteries for this camera? How many batteries does one carry for a day of shooting with this camera?