Battery controller and junction box with the same battery controller

A junction box provided between a high voltage battery and a load, on which a predetermined high voltage is applied from a high voltage battery, the box comprising:

• a high voltage system portion which receives a high voltage from said high voltage battery and supplies to said load;
• a low voltage system portion which generates a predetermined low voltage based on said predetermined high voltage and supplies to a low voltage battery and said load;
• a high voltage system power component detecting means for detecting a voltage value and a current value in said high voltage system portion;
• a low voltage system power component detecting means for detecting a voltage value and a current value in said low voltage system portion;
• a high voltage battery remaining capacity measuring means for collecting predetermined plural pairs of voltage value and current value based on the voltage value and current value detected by the high voltage system power component detecting means, obtaining an approximate straight line on current-voltage coordinates according to least square method based on the predetermined plural pairs of the data, and obtaining a voltage value according to the approximate straight line and a predetermined current value so as to estimate a remaining capacity of said high voltage battery;
• a low voltage battery remaining capacity measuring means for collecting predetermined plural pairs of voltage value and current value based on the voltage value and current value detected by the low voltage system power component detecting means, obtaining an approximate straight line on current-voltage coordinates according to least square method based on the predetermined plural pairs of the data, and obtaining a voltage value according to the approximate straight line and a predetermined current value so as to estimate a remaining capacity of said low voltage battery;
• and
• a means for dispatching an instruction for charging said high voltage battery and said low voltage battery when it is determined that the remaining capacity of each of said high voltage battery and said low voltage battery estimated by the high voltage battery remaining capacity measuring means and the low voltage battery remaining capacity measuring means is below a predetermined value.