Battery health
So I bought my son a refurb iPhone 11 128gb . It was grade a looked perfect and is working fine . But… when we got it in dec the battery health was 100% . Now 3 months later the battery health is 89%!!! he is not on it that much so it’s not from crazy use . It has been falling a % or so about every 2 weeks now
I wonder why this is ?
im going to send it back as I purchased on Amazon but it just seems very very odd
any thoughts ?