The architect pass made SAFETY-37, TEL-06 and TEL-08 one systemic problem - "a stale reading holds its last value and reads healthy" - and this builds the single policy. Both consumers the card names are gated by one change, and neither consumer needed a line: `SignWatchdog.evaluate` already CLEARS its window on a None measurement and `circulating_w` already returns None for a roster with a missing term. Neither could ever receive one. The gate is the piece that was missing BETWEEN the shipped read and the shipped checks. ⚠️ ONE CRITERION IN THE CARD COULD NOT BE IMPLEMENTED AS WRITTEN, AND SAYING SO IS THE MAIN CONTENT. The card says "only arrival separates them". At this layer arrival cannot: `read_inputs()` polls Home Assistant's state cache about once a second and HA answers 200 with a number whether or not the publisher behind the entity is alive, so both members of the pair arrive identically for ever. test_freshness.py part 1a BUILDS the arrival-age gate the card asks for and grades it failing - the age is 0.0 s at every instant of both runs, a threshold that can never fire, which is TEL-06's own defect one layer up. The half of the rule that survives is honoured absolutely: nothing here reads a Home Assistant timestamp, and the check asserts the module contains no `last_updated`. So the criterion became: a reading is stale when it has not moved through a change it was OBLIGED to follow. STALE <=> unchanged >= 35 s AND |standing| >= 250 W AND |standing - standing when the reading last changed| >= 250 W Latched until a different value arrives. `Inverter.batt` becomes None - never a held number - which is a missing input, which §11.1 rule 1 answers with 0 W. WHY A CONJUNCTION AND NOT A THRESHOLD, MEASURED 2026-09-06. Replaying the committed 30-day capture of this house's own 1 W power entity (485,841 samples out of HA's recorder, where a row exists only on a CHANGE, so the gap between rows IS the unchanged duration every consumer saw): the longest legitimate unchanged run is 263.2 s, held at -899.0 W. A false-positive-free threshold would have to exceed that, and 263 s is 3.5x too slow for a consumer that trips at 75 s. There is no admissible threshold. Every one of those long runs is under an UNMOVING load, which is what the travel term keys on. THE BOUND, derived at both ends and graded against the shipped config.yaml. Floor 17.0 s = 6.0 plant settle (NOTES §5.9, measured 2026-08-22) + 10.0 ESPHome publish (firmware/goodwe-master.yaml:181) + 1.0 read period (run_control's asyncio.sleep(1)). Ceiling 75.0 s = min(circulation_hold_s 75, unit_sign_disagree_s 85). Band [34.0, 37.5]; 35 is a CHOICE inside a DERIVED band and the check says so - the first draft claimed the band held one integer and went red on its own first run. MOVE_W is the LARGEST admissible value, unit_sign_disagree_w, because below it the consumer cannot speak at all. SoC is STATED, NOT WIRED, and BOUNDS carries it with wired=False and the reason. Its obligation term is energy through the pack, not command travel - a rested pack holds a percent for hours under a 0 W command - and K needs a usable capacity nobody has measured. That is TEL-08's; the record says so. ⚠️ BEHAVIOUR CHANGES AT THE SHIPPED ROSTER OF ONE, and it is named rather than hidden: a FROZEN register now stops the site where it used to read as a healthy measurement for ever. That is HW-01, which was a one-inverter site. A healthy install is unchanged, asserted over sixty reads of a dithering register under a reversing command. A false verdict fails toward 0 W behind the existing stale_input_s hold and clears itself on the register's next move. ⚠️ BOTH UNITS IN EVERY TWO-INVERTER FIXTURE ARE INVERTER A with different numbers passed in; inverter B does not physically exist (~2026-09-12). MUTATION: 16 mutations against a purged, :ro, python3 -B tree, fingerprinted before and after every revert. One survivor, and it is the finding - dropping the magnitude term left every check green because no fixture separated "the command travelled 250 W" from "the command ended up above 250 W". Closed, and recorded as MUTATION.md habit 17. A second process defect is habit 18: a mutation run that timed out between the edit and the revert left the module mutated on disk and nothing announced it. 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
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
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.