Energy and battery
Battery complaints arrive without timestamps, without a reproduction, and usually without any way to tell your app apart from the six others that were awake at the same time. This module is how you turn one into a chart.
Two different questions
Section titled “Two different questions”“What is this app costing right now?” is a live question — capture a session and read the energy counter alongside CPU, GPU and network. See Performance monitoring.
“What drained the battery overnight?” is a historical question, and the live counter cannot answer it because nobody was watching. That is usage history, which reads what the device recorded on its own.
What the energy figure means
Section titled “What the energy figure means”It is an impact figure derived from what the app kept busy, not a milliamp-hour measurement. Treat it comparatively:
- This build against the previous build, same interaction.
- Your app against a competitor doing the same thing.
- The same screen with a feature on and off.
An absolute number on its own is not a finding.
The usual suspects
Section titled “The usual suspects”| Behaviour | Why it costs |
|---|---|
| Location updates | Continuous GPS is one of the most expensive things a phone can do. Precise-when-moving is far cheaper than always-precise. |
| Keeping the screen awake | The display is often the single largest consumer. A view that disables idle timeout costs more than any amount of computation. |
| Background refresh | Cheap once, expensive every fifteen minutes. |
| Chatty networking | Radios cost most when they wake. Ten batched requests beat a hundred trickled ones, even at the same byte count. |
| Never-idle timers | A repeating timer prevents the CPU from reaching its low-power states at all. |
| Video and animation | Continuous GPU work, plus the display at full brightness. |
A method that produces evidence
Section titled “A method that produces evidence”- Charge the device to a known level and unplug it.
- Capture a fixed interaction — five minutes of the screen in question.
- Repeat with the suspected cause removed.
- Compare the two energy traces, and the CPU / network / location activity underneath them.
- For the overnight case, come back the next day and read usage history instead.
Attach both captures to the ticket. A complaint answered with two traces stops being an argument.
Cross-checking with the device
Section titled “Cross-checking with the device”The device’s own Settings → Battery screen gives per-app percentages over 24 hours or 10 days. It is coarse, but it is what the user is looking at when they file the complaint, so it is worth reading the same screen they are.
KeyMob’s history goes further back and breaks the same period down by which hardware each app kept awake.
Free tier limits
Section titled “Free tier limits”The data-analysis module — battery and charging, apps and energy use, wireless, sensors and the rest — is a paid feature. See pricing.