A detecting switch which is turned on/off in accordance with whether or not primary batteries have been attached to a primary battery holder is provided. In a normal state where no primary battery is attached, terminals (a, c) of a charge change-over switch are connected by a detection signal of the...http://www.google.com.au/patents/US20050127871?utm_source=gb-gplus-sharePatent US20050127871 - Battery pack
