So the Google Now launcher that I was quite happy with has been updated. One of the features added was that now you can say "OK Google" on any home screen.

That sounds pretty low impact, if of dubious usefulness. Since the update, my battery life was much worse. Have now turned off the OK Google voice feature completely and battery life seems back to normal.

I now have to press the voice search button like in the old days to do a voice search because I can't see a way of reverting it back to the way it used to be. No biggie.

So if your battery life has just tanked that is something to try, found under apps in the "Google Settings" app.