X Engineering alternator regulator — cherry hardwood enclosure installed in a boat cabin beside a chartplotter

Open-source alternator regulation for lithium battery systems

Basics

12 / 24 / 48 V universal. P-type and N-type alternators. Three-stage charging with tail-current detection and re-bulk logic. Third-party BMS integration.

Control architecture

Three cascaded PID loops with position-form PI, anti-windup, and bumpless transfer on every mode change. Smooth charging that won't spike, oscillate, or hunt.

Safety

Multi-layer thermal, voltage, and current protections, with redundant hardware safety that stops output even if firmware fails. Conformal-coated, EMI-hardened, reverse-polarity-protected — built for the marine environment.

Health Monitoring

Learns the alternator's output for a given RPM, field, voltage, and temperature — then flags deterioration. A physics-based life model predicts time-to-failure.

Performance & Comfort

Compare live speed to your best polars against wind and sea state — tune sail trim, spot a fouled bottom. The 6-axis IMU computes a Motion Sickness Index plus anchorage and passage comfort scores.

Strava-style fleet community

Global leaderboards for distance, days at sea, alternator and solar output, speed by boat type, and much more. Public fleet stats page.

History

80 hours of high-resolution data stored locally; unlimited cloud history on top. Long-trend plots across years of cruising.

Battery Monitor

Built in 20-bit voltage and current resolution (TI INA228). Benchmarked against BMV-712. No second device required — use any existing shunt.

Sensors

Digital alternator temperature sensor, Hall-effect alternator current sensor, 6-axis accelerometer + gyro, precision barometer.

Connectivity

NMEA 2000 (CAN), Victron VE.Direct, WiFi, cloud sync, secure OTA updates. Pulls wind, GPS, and heading from your boat network.

Easy installation

Splices into your existing wiring — no proprietary harnesses. Standard ethernet cables available anywhere. WiFi access-point mode for first-time setup.

Open everything

Schematics, source code, design documentation — all published. No black boxes, no secrets.

Connector panel — terminal blocks, RJ45 jacks, M12 NMEA 2000, USB-C

Cruising Network

Each regulator can opt in to a shared, anonymous fleet dataset. Leaderboards, records, and fleet-wide statistics, built from what the regulator already measures — speed, position, energy, weather, and more.