There are some common Toyota Prius battery problems that have been reported by Prius owners. The battery is the sole source of electrical power for the vehicle. This makes it prone to “self discharging” during periods of non use. Because of the constant charge cycles, the battery will sometimes die unexpectedly. Additionally, in order to extend the batteries life, and ensure it performs as designed, it must be recharged every two weeks. Diagnosing battery problems are troublesome because there are not many service centers, outside of Toyota, that are knowledgeable enough to work on them.