Determining the State of Charge (SoC)

An approximation method is used to determine the current state of charge (SoC). The SoC is determined based on a nominal value for the maximum usable capacity, taking into account the current energy consumption. However, the actual available capacity and performance are influenced by the ambient temperature, self-discharge, the thickness of the passivation layer and the discharge profile (current curve over time). These influences can only be taken into account to a limited extent. As a result, the battery or rechargeable battery may be depleted before the displayed SoC reaches 0. The same applies to the remaining device service life, as this is calculated based on the current SoC. However, experience shows that despite the influences of temperature, self-discharge, passivation and discharge profile, which are difficult to take into account, the approximation method provides reliable SoC values in over 95% of cases, so that the remaining device service life can also generally be considered reliable.