Abstract: This invention is a system and method for causing a rechargeable battery pack to enter a low power mode. The system includes a resistive divider, a switch, a battery cell, and a safety integrated circuit. When an external voltage is applied to the resistive divider, the switch turns on. With the switch on, the safety integrated circuit senses only a fraction of the cell voltage and therefore puts the battery pack into a low power, or sleep mode. The battery is returned to normal mode by connecting a charger to the battery pack.

Abstract: A battery pack (100) includes a battery cell (102), a power switch (104), a regulator circuit (106), control circuit (108), electronic drive switch (112), and a mechanical driver switch (116). The battery pack is placed in the hibernate mode by sending a hibernate message to the control circuit from an external device (134). The control circuit removes a control signal from the electronic driver switch, causing the power switch to open, removing power from the regulator circuit and all attached circuitry, including the control circuit. No current flows from the battery cell past the opened power switch, and the battery pack is then in the hibernate mode. To wake up the battery pack, the mechanical driver switch is actuated by a user, causing the power switch to close, allowing current and voltage from the battery cell to power up the regulator circuit, which in turn powers up the control circuit. The control circuit applies a control signal to the electronic driver switch to hold the power switch closed.