Patent ID: 7521894

Claim:
A device combination system, comprising: a plurality of devices each including a circuit operated by being supplied with power, wherein said system comprises such a structure that a battery is mounted on at least one power supply device and a plurality of devices including the power supply device, which are optionally selected from the plurality of devices, are combined with each other and operated by being supplied with power from the power supply device, wherein the power supply device comprises: a setting section to set an END setting value, which determines whether the battery mounted on the power supply device is in an unusable state that it is exhausted to a dead level, the END setting value being set according to parameters received in said setting section and transmitted from the combination of the plurality of devices; a detecting section to detect the unusable state of the battery using the END setting value set by the setting section as a criterion of determination; and a memory device which stores said parameters which are transmitted from said plurality of devices, wherein said setting section comprises a central processing unit (CPU) which is connected to said memory device via a bus, the respective parameters of said plurality of devices being written to the memory device via said bus under control of said CPU.