HI, I have had my 6S for 16 months from new and on latest 11.2.6. Recently the battery seems to be much worse, especially when using messages. It went down from 62% this morning to 29% in about 3 hours and all I did was one long phone call but about 20+ texts. I know I could maybe get the Battery swapped but my last run of coconut battery showed health of 96% with 158 load cycles. I am considering an upgrade but would I still get the same issue if I went for a 7 or 8, and therefore should I get the plus which has a bigger battery? Is there a website that compares the batteries properly and is not too partisan?! Many thanks for ideas etc.