| 摘要 |
PROBLEM TO BE SOLVED: To indicate and output the remaining time of service life of a battery by grasping the variance of temperature in the installation environment of the battery and computing the remaining service life thereof on the basis of the estimated service lives at respective temperatures. SOLUTION: The temperature (ts) on the surface of a battery is measured every one hour, and its data is added to the previously accumulated temperature data (SUMTMP). The sum is divided by the number of measuring times to obtain an average temperature (tk). Next, a life acceleration factor (fL1) and a life subtraction value (Lb) corresponding to the data (ts) are obtained from a data memory 9, and (Lb)-(ts)×(fL1) is operated to obtain a new life subtraction value (Lb). Further, a life acceleration factor (fL2) corresponding to the temperature (th) is led from the memory data 9, and (Lb)/(th)×(fL2) is operated to obtain a standard remaining life time (RL). In addition, the installation date of the battery stored in the memory data 9 and the present time of a calendar IC 10 are compared with each other in order to obtain a passage time (YPST) after installation of the battery, then the estimated remaining life time is indicated on an indicator 13 on the basis of operation of (RL)-(YPST).
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