Abstract: A battery control module for a battery system comprises a voltage measuring module that measures battery and a current measuring module that measures battery current. A state of charge (SOC) module communicates with the current and voltage measuring modules and estimates SOC at least one of when an accumulated charge swing during charge is greater than or equal to an accumulated discharge swing during a prior discharge and a negative of a charge current is within a predetermined window of a negative of a retained discharge current during the prior discharge and/or when an accumulated discharge swing during discharge is greater than or equal to an accumulated charge swing during a prior charge and a negative of a discharge current is within a predetermined window of a negative of a retained charge current during the prior charge.

Abstract: A system for determining an operating limit of at least one battery according to some embodiments of the present invention comprises a voltage module that measures a voltage V across at least one battery during first and second periods. A current sensor that measures current I supplied by the at least one battery during the first and second periods. A limit module estimates an ohmic resistance R0 based on at least one of a temperature of the at least one battery and a time difference between the first and second periods, and that estimates a sum of a polarization voltage VP and an open circuit voltage V0 of the at least one battery at the second period based on the voltage V and current I of the at least one battery at the first period and an ohmic resistance R0 of the at least one battery.

Abstract: A system for determining an operating limit of at least one battery according to some embodiments of the present invention comprises a voltage module that measures a voltage V across at least one battery during first and second periods. A current sensor that measures current I supplied by the at least one battery during the first and second periods. A limit module estimates a sum of a polarization voltage VP and an open circuit voltage V0 of the at least one battery at the second period based on the voltage V and current I of the at least one battery at the first period and an ohmic resistance R0 of the at least one battery.