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).
Thanks for your input, but we need to narrow down the battery issue first. Searching for battery issues on this forum will give a zillion results, which can be pretty overwhelming.