We had been spending an exorbitant amount of money and time on store-bought use-once batteries for my cameras and testing equipment in our home inspection business where we often take 200 to 300 flash photographs on a single day. Those one-time use store-bought batteries, while advertising a long shelf-life (if never opened) often failed half way through a project and often when we were 20 miles from a store. So we tried Tenergy Power AA rechargeable batteries with the charger tray. The first thing I noticed is that these rechargeable batteries have a much higher amperage rating and then I notices that they did NOT fail half way through a photography project. Rather they often last through 2 or 3 projects before needing a recharge. My cost of electrical battery power has dropped from retail to wholesale. We are extremely pleased with this system and would recommend Tenergy Power to anyone who relies on battery power for lighting, photography or emergencies. It saves a money and time!