| 摘要 |
PROBLEM TO BE SOLVED: To avoid excessive discharging of a battery by judging that the residual capacity of the battery is decreased when a detected battery voltage value is lower than a voltage threshold which is set from battery current, or when a detected discharge current estimation value is in excess of a discharge current estimation threshold. SOLUTION: The detected value of a current sensor 37 which detects current flowing through a motor 17 from a battery 21, and the detected value of a voltage sensor 36 which detects voltage across the battery 21 are inputted into a controller 22. The residual capacity of the battery is calculated from the detected value, and lighting, flashing or turning off of indicating lamps 40 to 42 is controlled from the residual capacity. Indicating level switching is conducted from the first to fifth voltage threshold values which are set from a battery current value flowing from the battery 21 (obtained by experiment for each battery type), and the discharge current estimation threshold. In this case, it is judged from both the threshold values until the residual capacity of the battery reaches a required charging level, and from only the voltage threshold when it reaches the required charging level. |
