There NEEDS to be a sleep mode or an option to turn off the controllers. I have just gotten my Oculus Rift S (3 days ago) and the controllers had gone through the included batteries in under 24 hours. I have swapped them out and been taking them out when I'm not using the Rift.

It seems like a major design flaw to have the controllers constantly running and to turn them off, having to take out the batteries. Not trying to repeat myself but there needs to be a way to turn them off or else you'll be constantly swapping dead batteries out or rechargeable ones (over time will die as well).