Multi-battery power supplies are becoming popular in electronic appliances of the latest generations, due to economical and manufacturing constraints. Unfortunately, a partitioned battery subsystem is not able to deliver the same amount of charge as a monolithic battery with the same total capacity. In this paper, we define the concept of battery scheduling, we investigate policies for solving the problem of optimal charge delivery, and we study the relationship of such policies with different configurations of the battery subsystem. Results, obtained for different workloads, demonstrate that the choice of the proper scheduling can make, in the best cease, system lifetime as close as 1% of that guaranteed by a monolithic battery of equal capacity