Method of operating a battery power management unit in an over-discharge situation, the power management unit (PMU) being part of a system, which further comprises a battery and a safety circuit (SCC) connected to the battery , wherein the safety circuit (SCC) comprises a safety switch (T2) and is operable in an active state, in which the safety switch (T2) is open, enabling only charging of the battery , an inactive state, in which the safety switch (T2) is closed, enabling charging of and drawing current from the battery , during charging of the battery , the method comprising the steps of: detecting an off-state of a device powered by the battery , detecting a state of the power management unit being in inactive state, in which an on/off control of the device is disabled, determining the state of the safety circuit (SCC) of the battery by stopping the charging of the battery , subsequently loading the battery with a test current to obtain a battery voltage (Vbat) and comparing the battery voltage (Vbat) to a test voltage (Vtest), in response to detecting that the battery voltage (Vbat) is below the test voltage (Vtest) indicative of the safety circuit (SCC) being in the active state, maintaining the power management unit (PMU) in the inactive state, in response to detecting that the battery voltage (Vbat) is above the test voltage (Vtest) indicative of the safety circuit (SCC) being in the inactive state, entering a pre-charge sate , wherein the battery is charged with a specified current (Ipc), entering in an active state by the power management unit (PMU) on detecting that the battery voltage (Vbat) is equal or above a predefined battery voltage monitor level (Vbvm), wherein the on/off control of the device is enabled, when the power management unit (PMU) is in the active state. an active state, in which the safety switch (T2) is open, enabling only charging of the battery , an inactive state, in which the safety switch (T2) is closed, enabling charging of and drawing current from the battery , detecting an off-state of a device powered by the battery , detecting a state of the power management unit being in inactive state, in which an on/off control of the device is disabled, determining the state of the safety circuit (SCC) of the battery by stopping the charging of the battery , subsequently loading the battery with a test current to obtain a battery voltage (Vbat) and comparing the battery voltage (Vbat) to a test voltage (Vtest), in response to detecting that the battery voltage (Vbat) is below the test voltage (Vtest) indicative of the safety circuit (SCC) being in the active state, maintaining the power management unit (PMU) in the inactive state, in response to detecting that the battery voltage (Vbat) is above the test voltage (Vtest) indicative of the safety circuit (SCC) being in the inactive state, entering a pre-charge sate , wherein the battery is charged with a specified current (Ipc), entering in an active state by the power management unit (PMU) on detecting that the battery voltage (Vbat) is equal or above a predefined battery voltage monitor level (Vbvm), wherein the on/off control of the device is enabled, when the power management unit (PMU) is in the active state. <EOS>