Because temperature changes significantly during the course of a discharge, the algorithm needs to be able to predict the future temperature. This is needed for temperature correction of battery impedance (R = Ra x exp(Rb x T)) during voltage simulation near the end of discharge. To achieve this, the algorithm collects T(t) dependence data during discharge. It is used to update parameters of a simple thermal model including a heat exchange coefficient and a thermal time constant. These parameters are updated at the same time as resistances. The algorithm also records the outside temperature (T_out) during relaxation periods. These parameters are used to define a function T(t, T_start) that calculates a temperature profile starting from present temperature, T_start, and continuing until the end of discharge.