BatTool

BatTool is a diagnostic and service tool for 18V power-tool batteries (BL18xx type). It connects over Bluetooth Low Energy to a small ESP32-based adapter that clips onto the battery contacts, and shows the full
real-time state of the pack.

WHAT IT SHOWS
• Whole-pack and per-cell voltages, including cell spread (balance).
• Pack temperature.
• State of charge (SoC) and state of health (SoH) as computed by the BMS.
• Charge count, manufacture date, factory capacity and status code.
• Lifetime stats: deep-discharge and overload events.

WHAT IT DOES
• Diagnoses why a pack stopped working (discharge, BMS lockout, permanent fault).
• Helps rescue deep-discharged packs — step by step, with safety warnings.
• Clears error flags and unlocks the pack when cells are within a safe range (double confirmation and voltage checks).
• Advanced EEPROM editor (hidden behind developer mode) — for technicians: reads and writes battery-frame fields with a backup and post-write verification.

SAFETY
• Destructive operations require explicit confirmation (typing the word WRITE).
• A backup is saved before every change and can be restored.
• Clear warnings about the risk of damaging the pack.

WHO IT IS FOR
For DIYers, power-tool repair technicians and anyone who wants to understand and extend the life of their batteries instead of throwing them away.

REQUIREMENTS
Requires an external hardware adapter (firmware "makita_bat") clipped onto the battery contacts, and Bluetooth enabled. Without the adapter the app cannot connect to a battery.

DISCLAIMER
This app is not affiliated with or endorsed by Makita Corporation. All trademarks belong to their respective owners. Battery modification is done at your own risk and may permanently damage the pack and void its
warranty.