I had this problem after updating my Nexus 7 to Marshmallow - lost full charge overnight . Tried the location services change and it made no difference, tried clearing the cache made no difference. I then reset the Nexus and set it up again. I've had no problems since and am getting the full benefit of the Doze feature. I use the Nexus in bed, rest of the time it sits on the bedside cabinet. I now go days between charges.
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