It does if you have it configured into auto-start/stop however with the SC-6501 and SC-6502, you have to manually wake it up (press the A button on the back) if it has gone to sleep (not simply stopped). With the older SC-6500, a spin of the wheel would also wake it up in addition to auto-start. According to Shimano, the change was made to address the criticism of premature battery drain. I have both the SC-6500 (on my MTB) and SC-6501 (on my RB) and have yet to see a major difference in battery life between the two.