RRDTool is great for storing these sorts of time-series archives, and it will generate pretty graphs as well. You could cobble together an app starting from the

RRDTool is great for storing these sorts of time-series archives, and it will generate pretty graphs as well. You could cobble together an app starting from these StackOverflow postings: Task Scheduling: http://stackoverflow.com/a/2725908 http://stackoverflow.com/a/2725908 RRD interface: https://pypi.python.org/pypi/PyRRD https://pypi.python.org/pypi/PyRRD Battery reading: http://stackoverflow.com/a/6156606 http://stackoverflow.com/a/6156606