A battery pack has a battery connection assembly for connecting to an electric motor with at least one lithium-based rechargeable cell therein and associated means for turning the at least one lithium-based rechargeable cell ON or OFF. The battery pack is configured to store a reserve within the at least one lithium-based rechargeable cell that is sufficient to start the engine electric motor. The battery pack can be activated by the associated means for turning the at least one lithium-based rechargeable cell ON or OFF to access the reserve to start the engine electric motor.