How I Built a Solar Battery Health Monitor with ESP32-S3 and a Remote Web Dashboard

The Challenge

• Health was a periodic multimeter reading, not a trend. By the time voltage looked “wrong,” damage was already done.
• Installers and owners did not share one record — photos in a chat thread were the log.
• A firmware-only logger is useless to a non-technical owner. A dashboard without honest sensing is theatre.

The Solution & Architecture

Same hardware-to-web loop as tank monitoring: sense on the pack, firmware that publishes trustworthy samples, software that stores history, UI that a remote owner actually opens.

1. 01

   Device

   ESP32-S3 with current sensing on the solar/inverter path so load and charge are measured, not guessed from voltage alone.

2. 02

   Firmware

   C++ sampling and thresholds so noisy current spikes do not become fake alerts.

3. 03

   Software

   Supabase-backed history for charge, load, and health so the UI can show weeks, not one snapshot.

4. 04

   Web dashboard

   React view for remote checks — the owner’s product is the chart, not the serial monitor.

The Tech Stack

• ESP32-S3

  Headroom for sensing plus Wi-Fi publish on a compact energy node.

• Current sensing

  Load and charge need amps, not only a voltage sticker on the case.

• C++ firmware

  Repeatable sampling and alert logic at the edge.

• React + Supabase

  Remote dashboard and stored trends without standing up a custom ops stack from zero.

The Results

• • Pack state is visible between site visits — not only during a technician’s hour on site.
• • Charge, load, and health sit on one timeline instead of a notebook.
• • The same pattern extends to more strings, alerts, or a facilities login.

Battery state without a truck roll — charge, load, and health in one view.