glenn schrooyenandClaude Opus 5
fc9bd89dca
main.py used to read the setpoint device's own +-5000 W rating, notice a
configured max_w above it, log one WARNING, and run anyway with
write_setpoint() quietly clamping. The operator's stated ceiling was never
the real ceiling and the only evidence had scrolled off the log. specs
§1.5 is explicit that such a config is refused at startup, not survived at
runtime.
validate_startup_config() runs in amain() before the broker, the web
server or any task exists, so a refusal cannot leave half a controller
running behind a UI. It refuses exactly three things, all sharing one
property - continuing makes a safety mechanism inoperative or makes a
stated limit untrue:
1. max_w outside the setpoint device's own rating.
2. No setpoint_entity: every write is a no-op, the device rating is
never read, and the ESP32 heartbeat that holds off the layer-1
failsafe never happens. It ran, looked healthy, and moved nothing.
3. A meter_source that can never produce a reading. These were already
caught, but they only DISABLED ingestion, which leaves grid None
forever: permanent inputs-missing, 0 W, and a status page
indistinguishable from a healthy meter nobody has fed yet.
Those last predicates move into p1.validate_meter_options(), which
build_source() also calls - one definition, two callers, not two
competing validators. ha_dsmr with half its entities and mqtt_p1 with a
blank topic gained the check the other two transports already had.
Deliberately not refused, because untidy is not unsafe: integrator_max_w
above max_w (the arbiter still bounds the wire to +-max_w, so the cost is
unwind latency - warned), a missing soc/batt entity (fail-safe and
already a red NOT READY banner), a setpoint entity that has not appeared
on the Core API yet (ESPHome is routinely late; re-checked in
run_control() once the real rating arrives), and a thin meter_poll_s
margin.
A refusal is legible as one: a banner saying in words that this is
configuration and nothing is broken, numbered problems, no traceback, and
exit 78 (EX_CONFIG).
Verified on the live add-on 2026-08-28, not by reading the code: a blank
setpoint_entity and a meter_poll_s equal to meter_max_age_s each stopped
the add-on with the banner and no stack trace.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Du77usMj8XNKNFZGmUiWDa
GoodWe RS485 Controller — Home Assistant add-on repository
Replaces a GoodWe battery inverter's vendor controller with a local one: holds net grid exchange at zero by emulating the inverter's smart meter over RS485, and runs the monthly battery maintenance cycle the vendor box was doing.
repository.yaml add-on repository metadata
goodwe_controller/ the add-on
config.yaml manifest + options schema (the per-site config form)
app/ the controller
control.py the control law — pure functions, no I/O
maintenance.py the monthly cycle state machine
hass.py Supervisor/Core API access
store.py persistent state in /data
mqtt.py optional status entities
web.py ingress UI
main.py orchestration, heartbeat, failsafe behaviour
test_control.py runnable checks — no framework needed
test_maintenance.py runnable checks — walks a full cycle in fake time
DOCS.md the add-on's documentation tab
firmware/goodwe-master.yaml ESPHome config for the T-CAN485
estop/rs485_log.py optional RS485 e-stop / bus witness
docs/GoodWe-RS485-Field-Guide.pdf the guide techs carry (10pp, A4)
docs/build_guide.py its single source - rebuilds the HTML and PDF
FIELD-GUIDE.md how to edit and rebuild the guide
Picking this up after a break? Read HANDOVER.md first — current state,
what is known broken, and what to do next.
Install
Settings → Add-ons → Add-on store → ⋮ → Repositories → add
https://gittea.kammenstraatha.duckdns.org/admin/goodwe-addon
then install GoodWe RS485 Controller.
⚠️ The repository must be PUBLIC for this to work. Home Assistant clones it
anonymously; against a private repo the store shows nothing and gives no useful
error. If it must stay private, install locally instead: copy
goodwe_controller/ into the machine's /addons/ folder, then
ha store reload — it appears as a Local add-on.
⚠️ Bump version: in goodwe_controller/config.yaml for every change.
Supervisor keys the built image by that version, so without a bump it silently
reuses the old image and your fix appears not to work — on your bench and on
every client's machine.
Requires Home Assistant OS or Supervised. Add-ons cannot be installed on HA Container or Core.
Read this first
The inverter holds its last command forever. It has no meter-timeout of its own — a controller that dies mid-command leaves the battery running until a human intervenes. Measured on real hardware: 5 kW of discharge held for 113 seconds after a controller went silent.
Three layers exist because of that, and only the third covers the Home Assistant machine itself dying:
- ESP32 watchdog — no fresh setpoint for ~30 s → command 0 W, and keep commanding it.
- Wind-down before firmware updates — 0 W written before the update starts.
- RS485 e-stop (optional) — writes 0 W after 30 s of total bus silence.
Sites sold without the e-stop must have the acknowledgement in FIELD-GUIDE.md
§10 signed.
Development
The control law and the maintenance machine are pure Python with no Home Assistant imports, so they run anywhere:
cd goodwe_controller
python3 test_control.py
python3 test_maintenance.py
Both must pass before shipping any change. They are not unit-test theatre —
each assertion corresponds to a rule whose absence produced an observed failure
on real hardware, and the comments in control.py say which.
Compatibility
Check the serial number, not the model name. Characters 6-8 of the serial are the platform tag:
| tag | platform | verdict |
|---|---|---|
ESU EMU ESA BPS BPU EMJ IJL |
105 — ES/EM/BP, AA55-era meter bus | supported |
SPB SPN |
745 — SBP G2 (GW…-SBP-20) |
no |
ESN ESC |
745 — ES G2 (GW…-ES-20) |
no |
ETU EHU BTU … |
205/745/753 — ET/EH/BT hybrids | no |
SDT DST MSU NSU … |
PV-only inverters — no battery to control | no |
A "-20" or "G2" suffix means a different platform with a different meter
protocol. The tags come from the goodwe library's PLATFORM_105_MODELS, which
is also what Home Assistant's own integration uses to pick a protocol.
- GoodWe ES / BP family inverters (AA55 / RS485 meter-bus generation)
- The protocol is reverse-engineered. There is no vendor contract, and a firmware change on GoodWe's side could break every installation at once. Say so when you sell it.