Ok so i have a couple things to say, im currently using iPhone 11 pro max which is currently 6 weeks old this day.
1. if you guys dont own iphone 11 series then you guys dont understand any of these. this problem happens only in iphone 11 series . How do i know? well because i have used iphone 7 plus and iphone x before and their battery is good . my iphone 7 plus battery health was at 88% after i have used it for 2 years and my iphone x battery health was at 95% after i have used it for 1 year . what about my pro max? its already at 98% after 6 weeks of usage. so stop telling us who own iphone 11 series to relax because it only happens to us
2. Apple changed the battery manufacturer from DESAY to SUNWODA (taiwan) in their 11 series which maybe the reason why iphone 11 series battery is bad . (no offense , but maybe the battery quality is different)
3. Apple's included fast charging brick is BAD. were not talking about quality here , but it may degrade your battery faster . this could also be the reason why iphone 11 series battery is worse than other series , because everyone charge their phone with fast charging charger everyday. totally different with iphone x and xr which supports fast charging but apple doesnt include the fast charger so maybe only few of the owner who use the fast charger have issues with their battery.so stop charging ur iphone with fast charger unless ur in a hurry.
4. 'Dont let ur battery goes under 30/20' , 'U can charge ur phone overnight because iOS have new optimized battery charging feature' well u know what , i already followed every single forums trick to make sure my battery is good but its just the same . my battery is now at 98% after 6 weeks . so once again the only way to have a good battery is dont use fast charger unless u really need to.
5. Dont use fake cases or cheap cases , they may harm ur battery . how? because if u use cheap or fake cases they may isolate the heat so the heat stay in ur phone and doesnt come out , and heat is batteries' enemy. but if you insist to wear those cases then its fine as long as you take it off when the phone gets hot.
6. Sorry my english is bad.