Abstract: The invention presents a method for estimating a direct current internal resistance of a battery, which defines a depth of discharge detection interval including a first threshold and a second threshold. When the battery is discharging, a currently battery voltage are periodically measured, a currently depth of discharge is calculated, and an open-circuit voltage is queried. The currently battery voltage is subtracted from the open-circuit voltage to obtain a voltage difference. The voltage difference is continuously accumulated to obtain a currently accumulated voltage difference. The currently depth of discharge reaches the first threshold or the second threshold, the currently accumulated voltage difference is a first accumulated voltage difference or a second accumulated voltage difference.

Abstract: The invention provides an estimation method for state of charge (SOC) of battery. A reference SOC is inquired from a look-up table based on a voltage of battery detected. A voltage threshold is subtracted from the voltage of battery to obtain a voltage difference. A current SOC or the reference SOC is divided by the voltage difference to obtain a first slope or a second slope. The first slope is divided by the second slope to obtain an adjustment ratio. An electric charge capacity for charging the battery is counted by a coulomb counting method to obtain a count capacity of discharging that is multiplied by the adjustment ratio to obtain an adjustment value. The adjustment value is subtracted from a previously recorded remaining capacity to obtain a new remaining capacity. The new remaining capacity is divided by a full charge capacity to estimate a new SOC of battery.

Abstract: The invention provides an estimation method for state of charge (SOC) of battery. A reference SOC is inquired from a look-up table based on a voltage of battery detected. A voltage threshold is subtracted from the voltage of battery to obtain a voltage difference. A current SOC or the reference SOC is divided by the voltage difference to obtain a first slope or a second slope. The first slope is divided by the second slope to obtain an adjustment ratio. An electric charge capacity for charging the battery is counted by a coulomb counting method to obtain a count capacity of discharging that is multiplied by the adjustment ratio to obtain an adjustment value. The adjustment value is subtracted from a previously recorded remaining capacity to obtain a new remaining capacity. The new remaining capacity is divided by a full charge capacity to estimate a new SOC of battery.