`_Series.at()` asked `s <= u < s + 1 h` of every point IN LIST ORDER and
returned the FIRST match. On the hourly shape every fixture in this
repository carried before TARIFF-08 that is right by accident. Belgium
moved to a 15-minute MTU on 2025-10-01 and the live day-ahead feed
returns 96 points at 900 s, where it is wrong twice over - measured
against the shipped code at 5059e28:
series: 02:00=0.10 02:15=0.11 02:30=0.12 02:45=0.13 03:00=0.14
ask +15min -> 02:00 0.10 <-- WRONG (wanted 02:15)
ask +60min -> 02:15 0.11 <-- WRONG (wanted 03:00)
ask +75min -> 02:30 0.12 <-- WRONG (wanted 03:15)
Inside the first hour the :00 point wins because its hour has not run
out. From the second hour on the answer is not even the top of the hour
- the first point still inside its own hour wins - so the error
compounds with depth into the series.
`arbitrage._act()` tests `here.start == v.cheapest.start` /
`== v.dearest.start` to decide whether this interval is the buy one or
the sell one. That identity almost never held, so the strategy idled
through exactly the interval it exists to trade, and read §8.3's
`here.provisional` and §17's `price < 0` off the same wrong point.
`static_tariff.py` emits hourly points, so static sites were never
affected; this is reachable only down the dynamic path TARIFF-08/09
made work.
THE RULE: a point covers from its own start until the next point's
start, and never more than one hour. Quarter-hourly takes 900 s,
hourly is unchanged, and a MIXED series - FCST-04's carry-forward puts
hourly carried points beside quarter-hourly firm ones, spacing
[900, 3600] in 70 % of soak samples - takes each point's OWN gap.
The one-hour cap is load-bearing: FCST-04 leaves an hour OUT when
nothing published it and yesterday has no value, and `at()` raising
Absence for it is what sends the caller to the static profile (§11.4).
Uncapped, "until the next point's start" would stretch the point before
a three-hour hole across the whole hole and answer every instant in it
with a stale price.
THE LAST POINT is given the same span as the point before it (one hour
when it is the only point). A flat one-hour tail would answer 00:30
TOMORROW with today's 23:45 price. The cost - a mixed series ending at
the firm/carried seam loses its last 45 minutes to Absence - is argued
in DECISIONS/TARIFF-14-the-window-a-point-covers.md §2 rather than
buried; the direction is the safe one.
`at()` now reads a point's NEIGHBOURS, so it would depend on
sortedness. It establishes that itself: the lookup index is sorted by
UTC start once, at construction, so no caller's list order reaches it.
A series handed its 96 points in reverse answers identically, and that
is a check. `covers()` shared the defect exactly - it has no rule of
its own, it asks `at()` - and is fixed by the same change; `window()`
did not, and its docstring now says why.
Nothing about §9.3 or a point's `start` changed. PricePoint still has
three fields; the span is derived from the neighbours, never stored.
Graded by test_price.py section 13 (900 s, 3600 s, mixed, holes, the
tail, caller order, duplicate starts, covers()/window(), the no-data
contract) and end to end by test_arbitrage.py section 10, which drives
decide() over a 96-point quarter-hourly day whose cheapest and dearest
quarters are deliberately NOT on a whole hour, plus §17, §8.3 and the
mixed series. Eight mutations, all red, including a ZERO-BYTE one on
the tail rule; byte deltas and what the arbitrage file could not see
are in the decision note §6. All 29 test files green.
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.