ELECTRIC POWER SOURCE APPARATUS

An electric power source apparatus includes a drive control apparatus and an auxiliary control apparatus. The drive control apparatus and the auxiliary control apparatus are configured to communicate with each other. When one of the drive control apparatus and the auxiliary control apparatus is a first control apparatus and the other of the drive control apparatus and the auxiliary control apparatus is a second control apparatus, the first control apparatus is configured to continue a function to communicate with the second control apparatus even when the first control apparatus is not able to normally communicate with the second control apparatus, and configured to execute communication with the second control apparatus when the first control apparatus is put into a state where the first control apparatus is able to normally communicate with the second control apparatus.