Last summer I upgraded my MacBook pro from a 2019 intel version to a M2 pro version. I gotta say I love it. It was so fast and smooth and the display was so nice.
But the one thing I loved the most was the battery life. My old intel mac got overheating and fans noise so easily, and the battery life could only last probably 3 to 5 hours. The new mac did so good about it. Almost never overheat, no fan noise, and last 8 hours in library with no problem.
I like taking my mac to a library and stay for half a day so longer battery life is really a big advantage to me. But I also got a little suspicious about it: can it really last more than 10 hours like Apple advertised? I even got paranoid about the battery after a couple of weeks and I found that my battery capacity dropped to 97%.
So finally I decided to write a script to record my battery data. And now after more than a year I get the result as below:
My battery capacity is 87% right now. When I started recording the data it was 97%. Roughly speaking the battery capacity dropped by 10% in a year. Of course the process was not smooth. Sometimes it dropped fast and sometimes it was slow.
I did hear about the 20–80 rule. There is a saying that keeping your battery levels between 20% and 80% is good for its health. It sounds like it makes sense. So I use a third-party app called AlDente to set a upper limit for my battery. As you can see from the distribution chart most of the the time my battery level stays around 70% — 80%.
Honestly I think dropping 10% of battery health in one year is a little fast. But fortunately it seems that my battery life has not been significantly affected:
Consumption rate is how fast my battery is draining when discharging. So if it is 12.5 %/hr, it means a full battery can last 8 hours at this rate. The monthly average consumption rate has not changed much during this year, around 10% — 12%, which means the average battery life is 8–10 hours. I think it is not bad.
Of course I also record some detailed data:
I know there are some other people who are also paranoid about their battery health like me, so I actually made it an app and launched it in App Store called PowerCharts. You can try it for free.
In summary my mac’s battery health dropped to 87% after more than a year. Luckily the battery life has not been affected. But at this rate the battery health would drop to 80% after two years of usage, which may require a battery replacement. I will see it in the next summer.
