A bicycle battery system includes a battery assembly and a battery lock. The battery assembly includes a battery and a handle assembly mounted to the battery. The handle assembly includes a handle mount, a handle plunger, and a handle. The battery lock is mounted within a cavity of a frame of a bicycle and configured to secure the battery assembly within the cavity. The battery lock includes a lock plunger, a movable latch, and a stationary latch. The lock plunger is configured to press a portion of the handle mount against the movable latch when the battery lock is in a locked position such that the battery assembly is securely mounted within the cavity. Responsive to the battery lock being in an unlocked position, the handle plunger is configured to cause the handle mount and the handle to pivot away from a face of the battery such that at least the portion of the handle mount engages the stationary latch of the battery lock.