Battery Guru: Battery Health

Android shows you the basics. Battery Guru goes deeper.

Get your actual battery capacity in mAh, track health degradation over time, measure real charging current, monitor temperature and see everything on an always-on display or homescreen widget. Battery Guru builds on top of Android to give you the full picture.

🔋 Battery Health and Capacity
Your phone shows a percentage. Battery Guru shows you whether your 4000 mAh battery still holds 4000 mAh or has quietly lost 20% of its capacity over time.
- Actual battery capacity in mAh compared to original design capacity
- Battery health percentage and capacity loss tracked over time
- Battery wear analyzed per charging cycle
- Charging cycle count from system data or calculated from your session history
- Maximum temperature recorded during each charging session

⚡ Charging Speed and Current
Not all chargers deliver what they promise. Battery Guru measures the real current flowing into your battery so you can compare chargers and cables by actual performance.
- Live charging current in mA and power in Watts
- Voltage readings in mV
- Estimated time to full charge with screen on and screen off shown separately
- Complete charging history with start time, end time and capacity per session
- Compare chargers and cables by their real measured output

📉 Battery Drain and Usage
When your battery drains faster than expected, Battery Guru shows you exactly where the charge is going.
- Screen on time, screen off time, awake time and deep sleep time
- Battery usage by app running in the foreground
- Wakelock monitor to identify apps and system processes keeping your device awake in the background
- Alerts when abnormal battery drain is detected
- Discharge rate and usage pattern history over time

🌡️ Temperature Monitoring
Heat is the leading cause of permanent battery damage. Battery Guru tracks temperature continuously and alerts you before harm is done.
- Real-time battery temperature with 24-hour history graph
- Custom high and low temperature alarm thresholds
- Minimum, maximum and average temperature per session

🔔 Alarms and Notifications
- Full charge alarm so you unplug at the right time and avoid overcharging
- Low battery alarm before you run out
- High battery drain warning when something unexpected is consuming power
- Temperature alarm for both overheating and cold conditions
- Status bar notification with customizable icon showing percentage, temperature or both
- Do Not Disturb schedule so alarms respect your sleep hours

📲 Always-On Display
See live battery stats on your lock screen without touching your phone. Battery Guru includes a fully featured always-on display built for AMOLED and OLED screens.
- Battery level, charging current, temperature and voltage on your lock screen
- Clock, notification icons and media playback controls
- Fully customizable layout and content
- OLED burn-in protection with automatic pixel shifting
- Auto-dim after a configurable time to preserve your screen

🖼️ Widgets and Overlays
- Homescreen widget showing battery level and temperature at a glance
- Widget with clock for combined battery status and time
- Draggable floating overlay with live battery stats over any app
- Overlay displays current, temperature, voltage and more in a compact view

🔵 Bluetooth Device Battery
- View the battery level of your connected Bluetooth devices inside the app

💎 Pro Features
- Ad-free experience
- Full session history for long-term battery health analysis
- Advanced overlays and complete health history
- Free premium: watch one short rewarded ad for 24 or 48 hours of premium access, available unlimited times

Battery Guru reads data directly from your device battery system. It measures and displays accurate values only. It does not claim to modify your battery, speed up charging or extend battery life in any way.

📧 Contact & Support
support@batterymentor.com

Recent changes:
Battery health is more accurate. Fixed the health number jumping far above the graph, reading twice as high on phones with two cells, and staying stuck too low.

The battery percentage now always matches the one your phone shows.

Fixed the first widget colour option doing nothing.

No more full screen ad when you reopen the app.

Also fixed the charging summary going missing, and a battery below freezing reading as 0 degrees.