KitKat 4.4.2 - battery life & tweaks, settings to review & optimize
Here's a link guide to what users might want to consider checking if you aren't getting "acceptable" battery life and/or standby time out of your Nexus 5 (and, other newer devices upgraded to/running KitKat 4.4.x (like my Nexus 7 WiFi tablet)
http://howto.cnet.com/8301-11310_39-...id-4.4-kitkat/
Screen brightness (disabled auto) & Screen On (timing out in 30 or 45 sec. instead of 2 minutes) - these will also drain your battery faster, as well as those notifications & LED flashes or alerts.
Owning 2 Nexus 5, Mrs. L gets 2 - 3 full days out of hers and I get 1 - 2 days on mine with GV/Talkatone, Twitter & FB running + Gmail & Outlook mail in the background.
If yours is running 4G/LTE mostly, it will "drain" faster vs. strong WiFi "n" signal - "H" speed is quite fast in my coverage area, and when I travel - I set it to 3G only to better conserve battery life. Have yet to pull out the charger/cord or external battery pack out of my Timbuk2 bag while on the move.