I've been generally impressed with the battery life on my Nexus 5. After a somewhat shaky start it settled in rather nicely, lasting up to 24 hours on a single charge—and this using the regular Dalvik runtime, not ART
Then something happened. I can't say for certain exactly what it was, but according to this reddit thread
other Nexus 5 users have experienced the same issue. Long story short, my battery life plummeted; it got so bad at one point that I went out with a 50% charge and came back with a dead phone only 45 minutes later.
As the title of this post would suggest that's no longer the case. Here's what I did to remedy the problem; maybe these steps will improve your battery life as well.