This set of traces was compiled from January 2007 - present. The traces contains battery usage data for 60 laptops. Apart from battery-usage data the traces also contain data on CPU utilization, disk space, and idle time for the laptop users.
"Users and Batteries : Interactions and Adaptive Power Management in Mobile Systems", Nilanjan Banerjee, Ahmad Rahmati, Mark Corner, Sami Rollins, Lin Zhong. In Proceedings of Ubicomp 2007, Austria.