BatteryTruth — Battery Health

Your phone says the battery is fine. The hardware often says otherwise.

BatteryTruth reads your battery's charge counter directly and works out how much
charge it actually holds today — then compares that against what it held when new.
The result is a health figure derived from measurement, not from a vendor estimate.

WHAT IT SHOWS

• Full-charge capacity in mAh, measured from the hardware gauge
• Health as a percentage of the original design capacity
• Charge level to two decimal places, updating live while you charge
• Voltage, current, temperature and charging state
• A trend chart, so you can watch degradation over months instead of guessing

HOW IT WORKS

BatteryTruth uses the public battery APIs that Android exposes to every app. It tries
three approaches in order and tells you which one produced the number on screen:

1. The gauge's own full-charge value, where the device exposes it
2. Charge counter divided by charge level — accurate on most phones
3. Integrating measured current over a discharge or charge cycle, for devices that
expose neither of the above

Every reading is labelled with its accuracy, and the app tells you plainly when a
number is not trustworthy yet — for example while charging, or at a low charge level,
where the gauge drifts.

HONEST ABOUT ACCURACY

Readings are most reliable at a high charge level, off the charger, with the phone at
rest. BatteryTruth says so on screen rather than quietly showing you a worse number.
Where a figure cannot be read at all on your device, the app says that too.

COMPARE AGAINST YOUR PHONE'S OWN FIGURE

If your phone reports a battery health percentage in Settings, enter it once and
BatteryTruth will show the two side by side. Many phones report a more flattering
number than the hardware supports. If your phone shows no figure at all — many do
not — the app helps you find your model's design capacity instead.

OPTIONAL EXTRAS

• An ongoing notification with live readings
• A home screen widget
• English, Traditional Chinese and Simplified Chinese

NO PERMISSIONS FOR THE CORE FEATURES

Reading your battery needs no permissions at all. The notification permission is
requested only if you switch the ongoing notification on. There is no account, no
tracking, no analytics, and no network access — your battery data never leaves
your phone.

A NOTE ON WHAT NO APP CAN READ

Cycle count and the manufacturer's own health calculation sit behind system
permissions that Android does not grant to ordinary apps on most devices. Any app
claiming to show your cycle count without root is estimating it. BatteryTruth does
not pretend otherwise.

Made in Hong Kong by MUDUOPRO LIMITED.