How it works
From battery signal to honest insight
No magic. Battery Health reads the signals Android provides, analyzes them locally, and tells you both what it found and how much to trust it.
- 1
Android exposes battery signals
Your device already reports battery level, voltage, temperature, charging status, and current via system broadcasts. Battery Health reads these — the same data any battery widget uses.
- 2
Snapshots are collected locally
While charging (or via periodic WorkManager snapshots as a fallback), the app records these readings over time. This happens entirely on your device.
- 3
Charging sessions are analyzed
Each charge is reconstructed into a session: duration, power gained, temperature curve, and stability. This is the raw material for everything else.
- 4
Health is estimated, not measured
Because Android doesn't expose a precise health percentage, capacity is inferred from charging behavior — how the battery takes and holds charge across sessions.
- 5
Confidence is computed and shown
The estimate is paired with a confidence level. A device with a charge-counter chip yields high-confidence readings; one with limited data yields a rougher estimate. You see both.
- 6
Everything stays on the device
There's no server. Insights, sessions, and estimates live in a local database you control. Export, recalibrate, reset, or delete it at any time.
The honest limits
Battery health estimation is inherently approximate. No Android app can read a factory-fresh capacity figure — that information isn't exposed by the system. What Battery Health can do is infer capacity from behavior and be transparent about the uncertainty. A high-confidence 90% and a low-confidence 90% mean different things, and the app never hides which is which.
This is the difference between a battery app that invents certainty and one that earns trust.