ESP32 12V Battery Monitor — Real‑time, connected battery health for your vehicle.
Turn any 12V automotive battery into a smart, observable system using an ESP32 plus proven sensors (INA226 voltage/current, hall current sensor, DS18B20 temperature). This project tracks voltage, current, and temperature, estimates State of Charge (SOC) using OCV + coulomb counting, and learns State of Health (SOH) via internal resistance (Rint) modeling—then publishes everything as clean MQTT JSON (including Home Assistant auto‑discovery).
New in Jan 2026: a BLE Command API lets you adjust key parameters at runtime (like battery capacity and Rint baseline) with simple text commands (case‑insensitive), processed safely via a queued main‑loop handler and persisted to NVS. It also supports adaptive sampling for real-world use (active driving vs parked/idle vs deep sleep), plus OTA updates via PlatformIO for fast iteration.
Perfect for DIY vehicle monitoring, overlanding rigs, fleet telemetry experiments, or anyone who wants reliable 12V battery insights locally over BLE and remotely via MQTT/Home Assistant. Repo: GitHub - tipih/12VBatteryMonitor