BLOCKER. `auto` was persisted and `sign_wd.tripped` was not, so reconstructing the Controller against the same store - which is what a container restart does - brought it back ARMED, into the same fault, unattended: tripped=False, banner back to NOT READY, and it resumed commanding -1000 then -2000 W before re-tripping 180 s later. "Restart the add-on" is the first thing an operator looking at a FAILSAFE banner and a 0 W inverter will try, and under a supervisor that restarts a crashed add-on it is a loop of three-minute wrong-direction bursts. DOCS.md's "it does not clear itself" was false across a restart. `sign_tripped` and `sign_reason` are Store keys now, beside the maintenance state and for the reason store.py's own docstring gives. Written the moment the trip happens - reason first, flag second, so a crash between the two can never persist a latch with no explanation - restored in Controller.__init__, cleared only by the operator's start. The regression is covered: reverting the restore fails seven checks in test_watchdog.py. Review follow-ups, no behaviour change: - The arming gate is tested against the REAL arbiter. It is the decision the ticket turns on and it was asserted in three comment blocks and verified by nothing - every case passed `following` in as a literal. Twelve claim configurations now derive it from resolve(), including the redirect case `winner == "loop"` alone would have got wrong and the `lo` limit that raises magnitude without flipping sign. - The MQTT `status: "failsafe"` value is tested. The check that claimed to cover it restated the line above it and never touched the payload. - The worked example described a config that does not ship: at the defaults maintenance_charge_w 2500 against max_w 2000 is an arbiter contradiction and 0 W, not a -2500 W charge. Rewritten at 1500 W. The contradiction is a real pre-existing bug - a default cheap-window maintenance charge silently never happens - filed separately and deliberately not fixed here. - Forward hazard recorded at the gate: `winner == "loop"` disarms the watchdog under any higher-priority SET, and a peak-shaving strategy at P_PEAK IS grid-following in sign, so it would blind this for every peak event. - disagrees() is public so the replay harness stops carrying its own copy of the predicate it grades. - held_s takes the clock instead of reading one. - The two limits are now each stated in both places rather than one each. - The no-false-positive argument is tied to control.py's freeze permitting the command to cross zero; under the shrink-only encoding control.py records as rejected, this would false-trip on a load step. - Measured figures corrected: 93.4 % / 4212 of 17280, per-cluster 0.3/0.9/10.5/0.0, and the near-circularity of those figures is now stated rather than leaned on. 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.