The utility model provides a hold battery operated devices and system, the device includes: charge the machine, fill motor relay, activation knob, train activation relay, battery and drop into relay,undervoltage protection relay, each relay all is provided with auxiliary contact, the machine that charges drops into the relay electricity with activation knob and battery respectively and is connected, battery input relay passes through train activation relay auxiliary contact and undervoltage protection relay auxiliary contact is connected with train activation relay, undervoltage protection relay electricity respectively to it is connected to drop into each load electricity of relay auxiliary contact and train through the battery, the activation knob is connected with train activation relay and train activation relay auxiliary contact electricity respectively, the quick -witted output that charges is provided with and fills motor relay, and it is parallelly connected with undervoltageprotection relay auxiliary contact to fill motor relay auxiliary contact to it is connected to drop into relay auxiliary contact electricity through train activation relay auxiliary contact with the battery.