An exemplary battery assembly includes a rechargeable battery cell that has a state of charge, a safety circuit configured to transition the battery assembly to a powerdown mode when the state of charge of the rechargeable battery cell is less than a predetermined threshold state of charge, and a hibernation control network. The hibernation control network 1) detects, by way of a phototransistor while the state of charge is greater than the predetermined threshold state of charge, a light beam having a predetermined wavelength, and 2) triggers, in response to the detecting of the light beam of the predetermined wavelength and while the state of charge of the rechargeable battery is still greater than the predetermined threshold state of charge, the safety circuit to transition the battery assembly to the power-down mode.
