I had my iPhone 6s battery replaced by Apple in November last year (i.e. 5,5 months ago). Today the phone crashed and peak power was disabled again. Admittedly it was relatively cold outside (about 8°C) and I used the phone for navigation. Battery health is given as 98%.
Nevertheless, I am rather annoyed that an almost new battery dies on me and I wonder if I should complain. Is the replaced battery covered by any kind of warranty and does it extent to peak power capability?