| 摘要 |
PURPOSE:To make it possible to accurately confirm the residual quantity of a battery, by providing a correction means for subtracting self-discharge quantity during a standing time from the residual quantity of the battery and correcting the residual quantity of the battery at the finish time of standing while correcting calculating and correcting self-discharge quantity corresponding to the residual quantity of the battery. CONSTITUTION:A battery residual quantity confirming circuit 12 is constituted of a current detection resistor 5, an amplifier 7, an A/D converter 8, an operational control part 9, a display part 10 and DC-DC converter 11. A battery 4 is allowed to stand after charging was finished and, when no current is flowed to the resistor 5, the control 9 judges the start of standing and begins to count a standing time. Subsequently, when load 6 is connected to the battery 4 by an operation switch SW, a discharge current flows to the resistor 5 and the control part 9 detects the discharge current to detect the finish of standing. At the same time, the control part 9 calculates self-discharge quantity during the standing time and calculates the residual quantity at said time to rewrite and store the same. When charge is started, the control part 9 calculates capacity during a sampling time from new residual quantity obtained by subtracting self-discharge quantity and performs cumulation and subtraction to successively display the residual quantity on the display part 10 at that time.
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