Battery Health Diagnostics & Cycle Monitor

Overview

Battery Health Diagnostics & Cycle Monitor (authored by Wo Bu Shi Chen Sang & Duo Rou Yu Yuan Pu Tao) provides accurate, hardware-level battery health information on rooted Android devices.

Instead of relying on proprietary OEM health estimates or third-party battery monitor apps that keep wakelocks active, this module interacts directly with kernel sysfs nodes exposed by the hardware power management IC (PMIC).

Technical Architecture & How It Works

1. Kernel Sysfs Gas-Gauge Reading

The diagnostic script (custom_script.sh) evaluates several hardware sysfs nodes depending on the SoC platform:

# Qualcomm State of Health (SOH) register
soh=$(cat /sys/class/qcom-battery/soh 2>/dev/null)

# Factory design capacity (uAh -> mAh)
charge_full_design=$(( $(cat /sys/class/power_supply/battery/charge_full_design) / 1000 ))

# Current maximum charge retention capacity (uAh -> mAh)
charge_full=$(( $(cat /sys/class/power_supply/battery/charge_full) / 1000 ))

# True capacity retention percentage
retention=$(( (charge_full * 100) / charge_full_design ))

2. Live Magisk Description Injection

Rather than requiring an APK interface, the daemon dynamically updates its own module.prop description field:

sed -i "s/^description=.*/description=[${timestamp}] SOH: ${soh}% | Real: ${charge_full}\/${charge_full_design} mAh (${retention}%)/" $custombattery_Path/module.prop

Users can observe their current battery health simply by opening Magisk Manager, KernelSU Manager, or APatch WebUI.

Verification & Manual Query

Execute the standalone diagnostic script directly via root terminal:

su -c sh /data/adb/modules/custom.battery/点我直接查询.sh