adminandClaude Opus 5
5d7e275df4
`slew_w: 1000` was derived on 2026-08-22 against a clamp of 1500 W, where "capping how far the loop can jump ahead of the inverter" was true because the rail itself bounded the excursion. The live install went to max_w 5000 and the constant did not move, so the loop crosses its whole output range in 10 s against a plant NOTES.md §5.10 measured at ~18 s. Measured on the owner's system 2026-09-05 11:43-11:46: a 3.4 kW export drove the setpoint 380 -> 5000 W in five 2 s ticks, the battery to -5154 W past a 5000 VA rating, and the grid from 3.4 kW of EXPORT to 2.8 kW of IMPORT. Nothing was broken; the rail moved. REPRODUCED FIRST, and one half of it is not reproducible at all. On plantsim.Plant and on an independent in-repo model: the setpoint stepping a full 1000 W per tick to the rail (48 of 51 export steps), and the meter crossing from export into import. The -5154 W figure is NOT reproducible in either model, because both clamp the plant at its rating - so the card's AC "battery no longer exceeds max_w in simulation" is unfalsifiable and was rewritten rather than met. THE DELIVERABLE IS THE RELATIONSHIP. SLEW_RAIL_FRAC = LOOP_TICK_S / PLANT_SETTLE_S = 2 s / 18 s = 1/9 slew_w = 0 now means FOLLOW THE RAIL - SLEW_RAIL_FRAC * max_w - exactly as integrator_max_w = 0 already means follow max_w. It is the shipped default: 222 W at max_w 2000, 556 W at 5000, 1067 W at a ~9600 W two-inverter site. validate.py rule 10 refuses an explicit value faster than that, graded against sum(unit_caps(opts)) - the roster sum, i.e. Controller.site_max_w - so a second inverter moves the bound with no operator action. VERIFIED BY BREAKING IT: restoring slew_w 1000 at max_w 5000 is refused, and the refusal names the rail, the crossing time, the measurement and what to do. Equality, one watt of slack, the live interim 400 and slew_w 0 at every rating all still start. GAIN IS THE CONSTANT THAT IS STILL WRONG, and it is NOT changed here. Over 51 export steps the over-absorption is FLAT in slew (958 W at 1000, 1081 W at 250) and monotone in gain (987 W at 0.6, 876 at 0.3, 435 at 0.2): slew_w bounds the OUTPUT, while the integrator moves gain*error per cycle and reaches a 5000 W rail in under three ticks whatever the slew is. Two control-law constants moving in one release on a running house makes the next measurement uninterpretable. ⚠️ N=2: the site rail becomes sum(max_w) ~ 9600 W (inverter B FROM DATASHEET AND SERIAL, not measured, and sim/plantsim.py's INVERTER_B is A copied), and the enforced ratio produces 1067 W there automatically. But a growing rail LOOSENS this bound, and the >= 900 W symptom goes stale at N=2 the same way the constant did - both stated in the record rather than left to be discovered. Nothing reached the inverter. The live install still runs the interim slew_w 400 applied by hand on 2026-09-05, which rule 10 accepts unchanged. 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.