cosmoai wrote:
Hi everyone, I recently bought a used MacBook Pro (M3 Pro). Battery health started at 100% and the cycle was 28 when I bought it. After this, it has dropped to 96% in about 1 month — roughly 1% per week. I'm charging it correctly (using the original/genuine charger), have the 90% charge limit enabled in Battery settings, and I'm not exposing it to heat (not always though, sometimes MacBook got hot because of hot weather even if I’m inside) or leaving it plugged in 24/7. Is this rate of decline normal for a used unit in its first month, or could this point to a battery issue from the previous owner's usage? Has anyone else experienced a fast initial drop like this on a used Mac that later stabilized? Cycle count: 33
Thanks in advance.
With a used Mac, you don't know its history so the battery might have experienced stress under the previous owner (after all, it was sold again for some reason, although if purchased from Apple or OWC, used Macs are typically in excellent condition ... from whom did you purchase it)
That said, I have a 2019 MacBook Pro. In July 2020 it showed 99% capacity (via the Coconut Battery app).
In Dec 2020 it showed 94%, which is a drop of 5%.
Fast forward several years, in July 2026, it showed 82%.
In August 2026 (now), it shows 86%. So it "gained" back +4%.
And the first time it showed 86% was back in April 2025, something like 16 months ago! Over those 16 months it has basically stayed "flat."
I don't think a short term change of +/- 5% is meaningful or can be measured with any certainty. Only over a long period of time, say 12 months, do these capacity estimates become meaningful. And even then, as WheelieNick indicates, it can come to a standstill for months, more than a year in fact as I saw with mine.
So for your Mac, it is too soon to really tell but I suspect over the next year you will see ups and downs and the over trend will even out.
In any case, Apple only considers a battery needing to be replaced when it drops below 80% capacity, or exceeds 1000 cycles. You aren't even close to those values.
Things that can wear out a battery faster include running it ALL THE TIME off the battery and running the charge level low, constantly. Or fiddling manually with the charge levels. If you use Apple's battery health management and optimized charging option, and connect to power whenever available (including overnight), as D.I. and leroy suggested earlier, you will get maximum use from your battery.
I used to check my laptop's battery capacity frequently ... until I realized that it was not helpful because the capacity estimate is "noisy" and goes up and down a lot. Every time I got "worried," a little later it would "gain" back "lost" capacity. So I stopped being concerned. My laptop has used up about 14% on the way to that 20% value at which point the battery should be replaced. That's 14/20 of the way, after 7 years. so one might expect another 3 years or so on the same battery, but batteries are not linear in this way, so it could be more or could be less. It's about as useful as worrying about the lifetime of automobile tires or automobile batteries -- bottom line is, don't mistreat them, and just replace them when they wear out.
