Stick-Up cam Solar 3rd G battery Life

Just installed two Stick-up Cam 3rd G Solar in Dubai. Solar facing the sun more than 8 hours a day. I have cut all actions down to min sensitivity, People only alert, now periodic pictures being taken. Bare minimum service. The battery only lasts a few hours. It's fine until the first movement is alerted, takes a 20sec video, and then after that nothing else is seen as recorded but the battery depletes within a couple of hours. What is wrong here?