IPhone Displays 0% Charge when Battery is Fully Charged IPhone 6

I Completed a hard reset, power cycled the battery from 0 to 100. Battery life shows 100% when connected to the Lightning Cable. When unplugged it immediately shows 0% but works just fine as it would if everything was ok. When I cycled power back on I would leave IPhone off while it charged for 10 hours. when plugged in battery life showed 0% went to 100%. Once unplugged immediately down to 0% But worked. Changed battery same issue. I'm out of ideas and searching the net proved futile.