So I have seen numerous things here related to battery life and here's what I can tell you.
1. Halo screen goes to sleep much sooner then the Deep Sleeper timer - like it should - this means battery life or lack there of is not because of the screen
2. During deep sleep... halo still checks in via wifi as can be seen on c4 logs and network activity - this will effect battery life
Deep sleep should basically nearly turn off the halo... any it should only check in once every x hours... for a brief period if that and go back to deep sleep. If that was the case the thing would last forever... think Apple Watch...