For more demanding applications the Panasonic XX High Capacity range are perfect. They provide a massive 2500mAH capacity (AA size), can be recharged 500 times, and will retain up to 85% of their capacity after a year in storage. They can also be used in sub-zero temperatures (-20°C) without issue. The high capacity allows you to take up to 5x more pictures with your digital camera. These batteries are pre-charged with photovoltaic generation.