DIN Time periodically updates the weather (if set) and that will consume some more power than watch faces without weather. If it is set to update more often, every 30 minutes, the impact on the battery will of course be larger than if set to every 60 minutes. Enabling seconds will also draw considerately more power than when disabled. All that said, according to the statistics available to Pebble developers, DIN Time has been given a battery grade of A. See below.