KXKM Batterie Parallelator — open BMU for 32 parallel battery packs

First public log, mostly to show the board in its real setting rather than the 3D render.

The main photo of this project is the v1 motherboard on the workshop bench: six numbered packs plugged on Anderson-style connectors, a bench PSU, the BMU on its aluminium plate next to the emergency cut-off switch, and a laptop on the serial console.

What the firmware does on that bench

- Each pack has its own INA237 on a 2 mOhm shunt (voltage and current) plus a temperature reading, and its own MOSFET switch, so a pack can be isolated from the bus in microseconds.

- Per-pack protection: under/over-voltage, over-current, imbalance detection.

- Auto-reconnection with exponential backoff, and a permanent lock (blinking red LED) after 5 faults until reboot.

- Soft-balancing by duty-cycling the switches, with opportunistic internal-resistance measurement.

- 26 host-side simulation tests run in CI without hardware (PlatformIO sim-host + ESP-IDF host tests), so changes to the switching logic are checked before anything is flashed.

Next

- Bring BMU v2 (production-ready, ERC clean) onto the same bench.

- Bench-validate the 48 V variant (BMU-v2-48v + MOSFET switch sub-board) with 13s Li-ion packs: parallel charging back-feed through pack BMS, MPPT profile at 54.6 V, inverter inrush.

Source and hardware files: https://github.com/KomplexKapharnaum/KXKM_Batterie_Parallelator