Patent ID: 7741807

Claim:
A battery charger comprising: a case having a battery attachment section capable of attaching longer sized batteries or shorter sized batteries; charging terminals for contacting electrodes at both ends of the longer sized batteries or the shorter sized batteries, when attached in the battery attachment section, and supplying charging current to those batteries; decision switch mechanisms for distinguishing the types of batteries attached in the battery attachment section; and a control circuit for controlling charging current for batteries attached in the battery attachment section based on signals from the decision switch mechanisms, the charging terminals comprising: a common charging terminal for contacting an electrode of the longer and shorter sized batteries; a longer sized battery charging terminal and a shorter sized battery charging terminal disposed at an opposite side of the battery attachment section relative to the common charging terminal, wherein a distance between the longer sized battery charging terminal and the common charging terminal and a distance between the shorter sized battery charging terminal and the common charging terminal are fixed; and a stepped shelf region disposed in the battery attachment section and having electrode alignment surfaces for holding an end of the shorter sized battery in a fixed position and aligning an electrode of the shorter sized battery with the shorter sized battery charging terminal to provide contact between the charging terminals and electrodes of the shorter sized battery, wherein the decision switch mechanisms are disposed inside of the stepped shelf region, and each of the decision switch mechanisms is a switch that switches when pressed by the battery electrode of either the longer sized battery or the shorter sized battery when attached in the battery attachment section, and the control circuit switches charging current between a first charging current and a second charging current to charge longer sized batteries or shorter sized batteries, respectively, depending on the OFF or ON state of the decision switch mechanism.