| 摘要 |
PURPOSE: To prevent a battery from becoming suddenly depleted during a conversation by switching only a transmission which consumes a current most to an auxiliary battery when residual change of a main battery drops. CONSTITUTION: When the battery charge of the main battery 16 becomes small, a changeover switch 14 is switched according to a voltage drop caused with a large current at the time of transmission and only the transmission part 4 which consumes the current most is switched from the main battery 16 to the auxiliary battery 12. At the same time, a message urging electric charging is displayed at a display part 9 and is shown to the user. The remaining conversation time of the transmission part 4 which is calculated from the charging quantity of the auxiliary battery 12 which is fully charged and the elapsed time from the switching is shown to the user through the display part 9, etc. Then the main battery 16 begins to be charged after the auxiliary battery 12 is completely charged so that the auxiliary battery 12 begins to be used in the fully charged state without fail when the main battery is switched to the auxiliary battery 12. Consequently, the auxiliary battery can be reduced in size having small capacity or make the remaining conversation time long with the same capacity. |
