I don't think at this stage there's much chance of a free battery replacement my friend because Apple are categorically denying there's a problem. As of yesterday Apple Care and my local Apple Store told me
this is absolutely normal battery health, therefore we won't change the battery 'Free of Charge' but you can pay £69 for a replacement battery!
My iPhone 12 Pro Max was delivered to me in the UK on 13 November 2020 as of writing this
Tuesday 8 February it is at just 89% see image below, even after I told them there is page after page on the Apple discussions site they still would not would not accept there is a battery health issue with the iPhone 12 Pro Max ??
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discussions.apple.com
I wish I could get my launch day 12 Pro Max’s battery replaced. I am at 85% now and charge twice a day and top up for 10 minutes riding to and and from work everyday. I have to carry a portable power bank with me in case it die when I’m not here a charger.
My iPhone Pro Max ? is now down to 88%. Here in the UK, between 2000 and 2014, more than 700 sub-postmasters were wrongly accused of theft. Almost all said no, it isn't us, it's your accounting system that can't count. With so many sub-postmasters saying the same thing, it just had to be the product not the individual.
Around the world there are so many iPhone Pro Max user's complaining about the rubbish battery health that we are suffering! Do we have to wait 7 years for Apple to admit there is a problem with the battery health, just like the sub-postmasters? Or is Apple so 'Cocker a Hoot' about who they are and continue to look down on their loyal 'whingeing' customers?
PS: I'm still waiting for a reply from Mr T. Cook