I unplug at 10 am (100%), tablet sits unused until I pick it up at 5:30 PM. Battery is down to 40%. Battery usage shows very slow decline until about 4PM, then STEEP decline to 5:30PM. Wifi is set to OFF when asleep unless plugged in. Any thoughts?
Welcome to Android Central! Try to catch that in the battery stats and show us. Charge up to 100%, then let it drain to 20-30% with normal usage, without charging in between. Then show us:
1. The main Settings>Battery screen.
2. The fullscreen battery graph screen (which shows Awake time and Cell Signal Strength).
3. The Screen category (to see total Screen On time).
4. The Cell Standby category, if present (to see Time Without Signal).
That sounds like a small dendrite. (See Lithium Battery Dendrite links if you want t learn what that means, but the short version is that the battery has to be replaced if it's throwing a dendrite.) I'm guessing that at 4:00, you have a LOT more than 40% charge left, which would be normal. (Even with the phone just sitting on the desk with the screen off, it consumes power. Even turned off, it consumes power. Even if you took the battery out of the phone, it would eventually self-discharge down to 0. But in 7 hours of screen off, it shouldn't consume much power.)
Download the Battery Doctor...it's in the store....run the app when you are done for the day it shuts down all unnecessary apps running. Also I got a qi charger for my bed table....just lay it down and it trickle charges all night. Also I turned my animation clocks to .5 from 1.0 (the factory default) my phone is 50% faster and it extended battery life. 1.0 is unnecessary.
It's constantly awake during the steepest decline, and I notice that the Google app is using a fair amount of battery. Do you have OK Google set for any screen? Open your Google Settings app, tap Search & Now>Voice>"OK Google" Detection, and try turning off From Any Screen.