Starting this mornng my Nexus 5 is using about 10% of the battery per hour, and that's with WiFi, data and location services off! The battery stats show Google Play Services as the main battery hog.
It appears I'm not the only one seeing this
, but I can't see any reports here so I thought I'd mention it.
When I turned my phone on this morning I got a message about a crash - I think in Google Play Services, and I suspect it was related to an update because update notifications for several other apps followed in quick sucession. For now I've done a factory reset and that seems to have cured it. Hopefully, if it's widespread, Google will be able to solve the problem fast.