Auxiliary power supply system, module, auxiliary power supply control method, and program

An auxiliary power supply control method for controlling an auxiliary power supply system including a plurality of electrical storage devices configured to supply power to a backup target,

• each of the plurality of electrical storage devices having a communication capability of communicating with an identical communications partner,
• the auxiliary power supply control method comprising:
• a provisionally selecting step including having each of the plurality of electrical storage devices provisionally select one of a plurality of first communication addresses as a provisional communication address of its own, the plurality of first communication addresses having been set for the plurality of electrical storage devices by the communications partner, the plurality of first communication addresses being as many as the plurality of electrical storage devices,
• a returning step including having each of the plurality of electrical storage devices return a response signal in reply to a transmission signal, to which the provisional communication address of its own is added;
• and
• a changing step including making each of the plurality of electrical storage devices change, when finding that any communication error has occurred while returning the response signal, the provisional communication address of its own into one of one or more unused communication addresses belonging to the plurality of first communication addresses that have been set.