glenn schrooyenandClaude Opus 5
f47f1f0129
A Belgian P1 meter publishes two UNSIGNED registers, not one signed figure. Until now the add-on asked the installer to bridge that gap with a template sensor, which put the sign convention of the whole control loop in a text box. This moves it into the EMS: net = import - export, derived once, in one place, with a test that fails if anyone inverts it. Two transports behind one contract, chosen by `meter_source`: the HA WebSocket subscribing to the DSMR integration's entities, and MQTT on a configurable topic. Everything downstream reads P1Ingest, so switching is a config edit. `meter_source: off` is the default and keeps the existing meter_entity path, so no installed system changes until it opts in. The other half is the timestamp. Every accepted sample is stamped at ingest with a monotonic clock, `meter_max_age_s` is applied to it, and the age is published as sensor.p1_sample_age_s for the ESP32's stale-input watchdog. That entity is recomputed against the clock every second rather than only when a telegram lands, because HA pushes state only on change: a meter frozen at a constant reading emits nothing and looks, to anything watching the value, exactly like a meter that has died. The age tells them apart. Deliberately absent: any fallback to an inverter-side power figure. The inverter's own AC power correlates 0.998 with battery power and 0.09 with the real meter, so failing over to it means regulating against your own output. A gap stays a gap - a reconnect emits no synthetic sample, and a rejected telegram never resolves to 0 W or refreshes the timestamp. Quarter-hour averages are time-weighted over clock-aligned blocks rather than a mean of samples, so a cadence change cannot bias the capacity-tariff figure, and only offtake is accumulated so a quarter of pure export averages to 0 kW. Per-phase import is kept separately: on an unbalanced three-phase load the phase sum and the connection net are different numbers, and only one of them is billed. test_p1.py: 99 checks, runnable with a bare interpreter and no meter. Includes an end-to-end run of the HA transport against a fake Home Assistant websocket. Stacked on SAFETY-04; nothing here touches control.py. 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.