A method and system for managing cache levels based on battery backup level are described. In one embodiment, the method comprises measuring the level of charge stored in an exhaustible power source. The method further comprises monitoring the level of charge stored in the exhaustible power source. The method further comprises adjusting the storage level of the cache in response to a detected change in the level of charge. In this way, the method ensures that adequate battery power is available to transfer the contents of the cache to a non-volatile data storage medium.