Google has confirmed that it's found a small problem in the Nexus 5 that's causing some users to have problems with battery life.
The issue is apparently being caused by the camera running in the background when it shouldn't be, causing high battery drain due to an overworked processor and resulting in 1% power loss every few minutes.
According to a Google engineer speaking on the Android code forums, the issue is down to the mm-qcamera-daemon process, and is likely triggered by apps such as Skype not playing nicely with the current iteration of stock Android 4.4 on the Nexus 5.
Google has noted the problem and has promised an imminent fix to the issue, although the engineer declined to give a timescale for when this would happen.
It's not good news if you're noticing the same thing on other devices, as users are being advised to speak to their manufacturers about the issue if it's not a Nexus.
If you are experiencing the problem and are using Skype, uninstalling the app can provide a short term fix – if you can't live without it though, you'll need to keep rebooting the phone to make things all work nicely again.
In our Nexus 5 review, we noted that the battery drain was much higher than expected for a device running the Qualcomm Snapdragon 800 chipset – it doesn't sound like this fix will resolve a weaker battery, but we're ferverishly awaiting the update to see how things improve.
From Google Forums