[doublepost=1522172266][/doublepost]As far as charging percentage - try not using the big ipad brick charger to charge the phone for a few days. I've found my viable battery percentage improved when using the slower chargers.
There is absolutely not evidence of that and that is merely anecdotal. There is nothing wrong with using an iPad brick. I have been using one for 5 years. The only time I don't use an iPad brick is when I'm traveling and there has never been a difference.