Battery health: what percentage is acceptable and when the reading lies
The number in settings matters, but on its own it is not enough. Here is what else to check.
Lithium-ion batteries lose capacity with every charge cycle. On an iPhone this shows as a percentage; on most Android devices you need an app or a service menu.
Where to see it
· iPhone: Settings → Battery → Battery Health.
· Android: Settings → Battery, and on some models the code *#*#4636#*#* or a diagnostics app.
What percentage is normal
· 95–100% — almost new, usually under a year old.
· 85–94% — normal for a phone 1–2 years old; everyday use is comfortable.
· 80–84% — noticeably shorter day; plan a replacement before long.
· Below 80% — Apple already considers the battery worn. Negotiate the price accordingly.
When the number lies
· If the battery was replaced with a non-original one, the percentage may not show at all or may sit permanently at 100%.
· An "Unknown Part" message on an iPhone means a non-original or improperly paired battery.
· A recently reset phone shows few cycles, but that does not mean a new battery.
The practical test
Run video or the camera for 10 minutes and watch how far the percentage falls. A sharp drop, or a shutdown at 20–30%, tells you more than any number.
Have a question about a specific device?
Call us or drop by the showroom — we check the device together.