A great deal is said about phone batteries, much of it out of date. Here is what battery engineers broadly agree on.
The first point is also the most important: heat. Sustained high temperature degrades capacity faster than the number of charge cycles, particularly when charging under heavy load.
Full charge is not a good resting state
The second is counter-intuitive: holding at 100 per cent is not ideal. Chemical ageing runs faster at a high state of charge, and keeping day-to-day use between 20 and 80 per cent is kinder.
Fast charging is not the villain
The third concerns fast charging. Modern charge management holds temperature tightly during the high-power phase and steps power down progressively; the effect is far smaller than commonly believed — provided cooling is normal.
- Leading factor: heat, especially charging under load
- Charge window: 20–80 per cent is kinder day to day
- Fast charging: overstated, watch cooling instead
- Long storage: leave around 50 per cent
The fourth applies to devices left unused: store at around 50 per cent and top up every few months, to avoid irreversible damage from deep discharge.
You do not see many pieces that show the process like this any more.
Clearly written, and the section on the data is more solid than most coverage of this.
I had not thought about it from this angle. It did shift my view a little.
I had not thought about it from this angle. It did shift my view a little.
Hope there is a follow-up. These things tend to drop out of view after a few weeks.