`generic_dayahead` could not read one byte of `api.energy-charts.info`, and
never had been able to. `_points_from_json()` asks for `doc["data"]`, a list of
`{start, price_eur_mwh}` objects; that document does not exist. Fetched live on
2026-09-10 the feed returns COLUMNAR parallel arrays and no `data` key at all -
`unix_seconds` (96 UTC epoch seconds, 900 s apart), `price` (96 floats),
`unit: 'EUR / MWh'`. Driving the shipped parser against that body:
`SourceUnavailable: the feed carried no 'data' list`. It is the only shipped
provider whose endpoint anybody has reached, so dynamic pricing did not work.
AND §11.4 MADE IT SILENT, which is why it survived to release: a parse error
becomes no_data, becomes the static profile, becomes arbitrage off - the
CORRECT degradation, saying nothing about the cause. A site would have sat on
the fallback indefinitely.
AND THE SUITE COULD NOT SEE IT, because every fixture was built from the
parser's own assumption. test_price.py, test_price_history.py and
test_static_tariff.py each built `json.dumps({"data": [...]})`, a shape invented
here and published by nobody, so the checks graded the parser against the
parser's guess - a closed loop no coverage inside it could ever have escaped.
MUTATION.md habit 19 records it as the fourteenth instance of habit 4 and the
first where the fixture and the code under test shared a SHAPE, not a number.
WHAT CHANGED
* `_points_from_columnar_json()` - a SECOND function, not a sniff. A parser that
decides which document it received is one that can decide wrong, and a
wrong-but-parseable response then becomes a price. Feeding the row shape to
`generic_dayahead` is now a graded no_data.
* Unequal arrays are refused in both directions, with the two lengths in the
reason. `zip()` stops at the shorter list silently, and a truncated `price`
array would have produced a real series missing the evening peak - traded on
as complete, where no data at all switches arbitrage off.
* A unit that is not EUR/MWh is refused. The plugin converts with a fixed
0.001, and `MAX_PLAUSIBLE_EUR_KWH` only bounds prices that are too LARGE.
* `unix_seconds` are read as UTC instants explicitly; §9.3's Brussels rendering
stays in `assemble()` rather than being copied into the plugin, where a
mutation could not tell it from a no-op (M4 proved exactly that on a first
draft, and the line was removed rather than fenced).
* A published null is dropped and logged with a count; an all-null body is
no_data named by this parser rather than by the boundary validator.
FIXTURES
Two unmodified response bodies under `scenarios/`, captured by hand on
2026-09-10: quarter-hourly (2026-09-10, 96 points at 900 s) and hourly
(2025-09-10, 24 at 3600 s - the same endpoint before Belgium's 15-minute MTU).
`energy-charts-be-price-captures.json` records the URL, retrieval time, unit,
licence-as-returned and a sha256 of each, and the replay RE-DERIVES the
checksums, so a fixture edited to make a check pass stops being a capture. Data
CC BY 4.0, Bundesnetzagentur | SMARD.de, via Energy-Charts (Fraunhofer ISE),
published without changes - the same BE-zone licence check DATA-02 established.
The surviving invented fixtures are renamed `synthetic_row_feed` at every call
site. `engie_dynamic`, `totalenergies_dynamic` and `eneco_eddy` are untouched
and have no capture: their URLs are unverified and withdrawing them is
TARIFF-07's open decision. Nothing should read their green checks as evidence
that those feeds parse.
MUTATIONS - 12, all red, no survivors. Purged tree, mounted `:ro`, `python3 -B`
(TEST-15). M1 drop the equal-length refusal; M2 make it one-sided; M3 drop the
unit check; M4 `assemble()` stops rendering at the Brussels offset; M5 read
`unix_seconds` as a naive local clock; M6 zero-fill a null instead of dropping
it; M7 drop the all-null refusal; M8 sniff for the row shape; M9 drop the
deprecated warning; M10 drop the dropped-nulls warning; M11 edit one price in
the committed capture; M12 point `generic_dayahead` back at the row parser -
red across all three price suites.
END TO END, LIVE, 2026-09-10: `resolve_tariff()` returns a `TariffPlan`,
`origin='provider'`, 96 quarter-hourly points, spacing [900] s, no decimation,
first point 2026-09-10T00:00:00+02:00 at 0.30608 EUR/kWh all-in. FCST-04's H1
fix was never theoretical. All 29 test files green.
STILL OPEN: `generic_dayahead` asks for no date range, so the default URL
returns one published day - a full 48 h horizon is reached only through §8.3's
carry-forward fill.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BwRLw7eKYj2byVdwB6kbjU
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 — routes only, status and configuration
config_page.py the configuration page's markup, style and script
configui.py its field model, built from the Supervisor's own
schema + translations — owns no key, label or rule
selfconfig.py reading and writing this add-on's own options,
with the validate-first / compare-and-swap gate
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
MUTATION.md how to run a mutation so the result means something
tools/mutation_run.sh the mutation harness - purges bytecode, then grades
tools/supervisor_selfapi_probe.py what the Supervisor really permits and
returns, run against its own release image
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. To prove a check bites - the way
almost every claim in this repository was established - mutate the module and
run tools/mutation_run.sh, which clears __pycache__ first. It is not
optional: a same-size edit reverted inside one second leaves CPython reusing the
old bytecode, and the run grades code that is not there. goodwe_controller/MUTATION.md
has the mechanism, the measurement, and what the flags do not do. 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.