glenn schrooyenandClaude Opus 5 bdd7f18a54
checks / unit (pull_request) Successful in 3m16s
OPT-04: charge cheap, discharge expensive - and only when it pays
Four cards built the price stack and nothing traded on it. app/arbitrage.py is
§10.1's priority 3, and it consumes all four rather than re-deciding anything:
whether a trade is permitted at all, on which two hours, against which widened
threshold is TariffPlan.arbitrage()'s answer, and that answer cannot be
obtained without first saying whether the peak guard is holding. §9.1's "peak
shaving outranks arbitrage" is therefore honoured structurally - there is no
path to a spread that skips the question - and again in the arbiter, where
P_PEAK (50) clamps a claim filed at P_ARBITRAGE (30).

A guard that never ran is not a guard that is clear. On meter_source off the
peak guard is never evaluated; that third state is carried as None and refuses,
because charging at the rail creates the billed quantity while nothing measures
the quarter. validate.py refuses that configuration too, along with arbitrage
armed with no price source and a SoC floor at or above the ceiling.

§17: never export into a negative price. The guard is on the hour being sold
into, not on the spread - a day priced -0.30 .. -0.05 clears any threshold and
its dearest hour is still negative. Buying in a negative hour stays allowed.

resolve_tariff() may open an HTTPS connection and the tick feeds the ESP32
heartbeat, so the fetch runs in its own task at a 30 min cadence and the tick
reads an attribute and an age bound. test_arbitrage.py section 8 asserts that
structurally on the shipped AST: a fetch put back on cycle() is red.

AC4 is NOT met and is not restated - this repository holds no price history.
Section 7 replays a synthetic year and asserts the property that does not need
real prices: every executed round trip cleared its own widened requirement, and
zero discharges landed in the 522 negative-priced hours. At the shipped 0.10
EUR/kWh threshold a realistic Belgian day/night site does not trade at all.
Reported, not tuned: that number and FCST-03's widening factors are one product
decision and it is the owner's.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015VXjA3LWccN1rJsk3okyPC
2026-08-31 01:36:09 +02:00

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:

  1. ESP32 watchdog — no fresh setpoint for ~30 s → command 0 W, and keep commanding it.
  2. Wind-down before firmware updates — 0 W written before the update starts.
  3. 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.
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