From the BMS
- Cell voltages for every cell of the pack (8 to 16 cells on typical home builds), with average, min, max and delta.
- Active balancer: on or off, balancing current, and the cells involved.
- Pack: voltage, current, power, state of charge, remaining capacity, cycle count.
- Temperatures: the pack probes and the power MOSFET.
- Cell wire resistance, where the board reports it: a quiet way to find a loose busbar.
- Warnings and protections as raised by the BMS.
Several boards
Many JK owners parallel two or more packs, each with its own board, addressed on a shared RS485 line. Reading all of them from one box is part of what we validate. Tell us how many boards you have when you order.
Where you see it
| Where | What |
|---|---|
| Screen | SOC, voltage, current, power, status, temperature |
http://moniwatt.local | Live cells, balancer, temperatures, alarms, daily curves |
| Home Assistant | Device with per-cell and pack sensors via MQTT discovery |
| JSON API | All values for Node-RED, Grafana, scripts |
| Remote dashboard (optional) | History up to 3 years, CSV, offline e-mail alerts |
What stays in the JK app
Changing protection limits, balancer start voltage or calibration remains a job for the official app. The box never writes to the board. It is a monitor, and a monitor that cannot misconfigure your BMS is a safer one.