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goodwe-addon/goodwe_controller/DOCS.md
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adminandClaude Opus 5 0a1e61dbc9 Packaged as a Home Assistant add-on, with a field guide
Turns the reference RS485 controller into something a technician can install
at a client site: a typed config form instead of YAML, an ingress UI that
names misconfiguration in words, and persistent state that cannot be broken by
a timezone.

Why an add-on rather than YAML packages or blueprints:

- Blueprints cannot create helpers, and the maintenance cycle is a state
  machine whose phase and completion date must survive restarts.
- YAML packages need filesystem access, a configuration.yaml edit and a
  restart - none of which belong in a client install.
- Add-ons authenticate with SUPERVISOR_TOKEN, so there is no long-lived token
  to generate, store or leak on someone else's machine.
- Requires HA OS/Supervised. Container and Core installs cannot run add-ons at
  all, which is a market decision, not an oversight.

The control law and the maintenance machine are pure functions with no Home
Assistant imports, and both ship with runnable checks (22 and 22 assertions).
Every assertion corresponds to a rule whose absence caused an observed failure
on hardware - the saturation duration term, the clamp-before-slew ordering, the
deadband, the sign convention.

One behaviour deliberately differs from the implementation it replaces: when
its inputs go missing this commands 0 W rather than replaying the last
setpoint. The reference version kept replaying, which the hardware watchdog
cannot catch - from the ESP32's side, Home Assistant is still talking to it.

Includes the ESPHome firmware (now parameterised: node name, inverter rating,
watchdog timeout) and the optional RS485 e-stop. FIELD-GUIDE.md carries the
commissioning gates, all judged on the wire rather than on how Home Assistant
looks, plus the written statement a site without an e-stop needs signed.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016NckgXecasQb2eSsPYNSW6
2026-08-23 01:15:25 +02:00

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# GoodWe RS485 Controller
Drives a GoodWe ES/BP battery inverter over its RS485 meter bus: holds net grid
exchange at zero, and runs a monthly battery maintenance cycle so the BMS can
balance cells and recalibrate its coulomb counter.
Installers: read `FIELD-GUIDE.md` in the repository. It is not optional reading —
it contains the commissioning gates and the failure modes.
## Before you start
You need:
- A GoodWe **ES / BP family** inverter (AA55 / RS485 meter-bus generation)
- The vendor's meter-emulating controller **disconnected** from the bus
- A T-CAN485 (ESP32) flashed with `firmware/goodwe-master.yaml`
- A grid-power sensor already working in Home Assistant, updating every ~510 s
## The safety model, in short
The inverter **holds its last command forever** — it has no meter-timeout. So:
- The ESP32 commands 0 W if this add-on stops refreshing for ~30 s, and keeps
commanding it.
- This add-on commands 0 W when its inputs go missing, when you stop control,
and when it shuts down.
- The **optional RS485 e-stop** is the only thing that covers this machine
dying. Without it, a failed host leaves the battery latched at its last
command until someone intervenes.
**If anything looks wrong: stop the add-on.** That commands 0 W and the
hardware holds it there.
## Configuration
### Sources
| option | required | meaning |
|---|---|---|
| `meter_entity` | yes | Net grid power. **Positive must mean importing** |
| `meter_invert` | | Flip the sign if the meter reports the other way |
| `soc_entity` | yes | Battery state of charge — use the **ESP32's own read** |
| `batt_entity` | yes | Battery power — again the ESP32's read, `+` = discharging |
| `batt_invert` | | Flip if needed |
| `setpoint_entity` | yes | The ESPHome `number.*_goodwe_setpoint_w` |
Use the ESP32's readings rather than the inverter's cloud or dongle sensors:
those serve cached values, and a stale reading here ends the maintenance charge
phase having charged nothing.
### Control
| option | default | meaning |
|---|---|---|
| `max_w` | 2000 | Hard limit on what may be commanded. Start low, raise after commissioning |
| `gain` | 0.6 | Correction per cycle. **At the limit — do not raise** |
| `slew_w` | 1000 | Maximum change per cycle |
| `deadband_w` | 15 | Ignore errors smaller than this |
| `step_w` | 10 | Quantisation |
| `saturation_w` | 500 | Divergence that counts as "the inverter is at a limit" |
| `saturation_cycles` | 3 | How many consecutive cycles before freezing. **Do not set to 1** |
| `heartbeat_s` | 10 | Refresh interval; must stay well under the firmware watchdog |
| `stale_input_s` | 15 | How long inputs may be missing before commanding 0 W |
| `auto_start` | false | Start controlling on boot (only after commissioning) |
### Maintenance
| option | default | meaning |
|---|---|---|
| `maintenance_enabled` | false | Enable the monthly cycle |
| `maintenance_interval_days` | 28 | Minimum gap between cycles |
| `maintenance_start_hour` | 10 | Hour of day a due cycle begins |
| `maintenance_discharge_w` | 2500 | Drain rate (exports the surplus) |
| `maintenance_charge_w` | 2500 | Charge ceiling, capped again by peak headroom |
| `maintenance_soc_floor` | 11 | Drain target — stay just above the inverter's own floor |
| `maintenance_soc_target` | 99 | Charge target |
| `maintenance_hold_min` | 120 | Hold at full so the BMS can balance |
### Tariff (all optional)
| option | meaning |
|---|---|
| `peak_forecast_entity` | Quarter-hour demand forecast, for capacity-tariff markets. Empty = no cap |
| `peak_cap_w` | The site's capacity-tariff target |
| `price_now_entity`, `price_avg_entity` | Dynamic tariff. Empty = never force a paid grid top-up |
On a capacity-tariff site the maintenance charge is capped by the headroom left
under `peak_cap_w`, and if the forecast goes over the cap the charge-only clamp
is dropped so the battery can shave the peak instead. Money outranks the
maintenance schedule.
### Site
| option | meaning |
|---|---|
| `estop_fitted` | Whether the RS485 e-stop is installed. Drives the warning banner |
| `log_level` | `trace`/`debug`/`info`/`warning`/`error` |
## The Web UI
The ingress panel shows live values, why the controller is commanding what it
is, and a **Commissioning** checklist that names any problem in words. It also
carries the three buttons: start/stop control, force a maintenance cycle, and
abort one.
## Status entities
If an MQTT broker is available the add-on publishes setpoint, grid power,
battery power, state of charge, maintenance phase and controller status by MQTT
discovery. This is observability only — the controller works fine without a
broker, and MQTT problems can never affect control.