Feature · 健康
Capacity, cycles, condition,and the habits behind them.
The three numbers macOS keeps but rarely shows: how much the pack holds today, how many full cycles it has behind it, and Apple's own condition verdict, unedited, beside the charging habits that shaped them.
Why it matters
“92% capacity” means nothing on its own. Fine for a three-year-old Mac, alarming for a new one. Health is a trend, not a score, which is why these numbers live next to your charge history instead of on their own.
The three numbers worth watching
- Maximum capacity. What the pack holds today against what it held new. See battery health for how the percentage is derived and why it moves in steps rather than smoothly.
- Cycle count. Full equivalent discharges, not plug-in events: two half-discharges count as one. Modern Apple Silicon packs are rated around 1000 cycles; see cycle count.
- Condition. The verdict macOS itself publishes: Normal, or Service Recommended. Sensei surfaces it verbatim rather than inventing a competing score.
Read it as a trend, not a score
Capacity readings are noisy day to day. They depend on temperature, recent cycles, and when the controller last recalibrated. A single 1% drop means nothing; the shape over months means everything. That's why the panel sits alongside the charge history rather than as an isolated number.
What actually moves it
Heat, time spent at very high or very low charge, and cycle count, in roughly that order. Most of what you can control lives in the charge limit and in avoiding long, hot, fully-charged sessions on a desk.
Frequently asked.
- What's a normal capacity after two years?
- Most Macs land somewhere between 85% and 92% after two years of daily use. Below 80% is where macOS starts recommending service.
- Why did my capacity jump back up?
- The battery controller recalibrates periodically, and readings before a recalibration can understate the pack. A jump of a point or two is normal; a steady slide is the signal.
- Does Battery Sensei read the battery differently from macOS?
- No. It reads the same firmware counters through IOKit and presents them without adjustment, including the condition string, verbatim.