glenn schrooyenandClaude Opus 5 706e625d99 SAFETY-42: a unit that stops delivering, and the discriminator the card asked for does not exist
A unit standing at a non-zero share and producing nothing is seen by NOTHING.
SAFETY-30's per-unit sign gate needs OPPOSITION on both sides of 250 W and a
unit at 0 W is not opposing, it is ABSENT. The site sum still agrees with the
meter in direction. Circulating power is exactly zero when one unit does
nothing. The only trace left is `reason == "saturated-freeze"`, which
clamp.py:93-96 documents as the alarm an operator learns to ignore. It is
HW-01's shape, which ran 6 h 25 m with all three layers spectators.

⚠️ THE CARD'S OWN DISCRIMINATOR WAS BUILT FIRST AND FALSIFIED, AND THAT IS THE
MAIN CONTENT. SAFETY-42 asks for "saturation persisting past N while
|grid error| > X, both derived". Run on the two-master rig it fails in BOTH
directions, and no (N, X) fixes either:

  FALSE POSITIVE  `plantsim.Plant.limit()` returns 0 W for a discharge command
      into a pack at its own floor, and a wedged unit produces 0 W too. Load
      2000 W, equal weights, 2000 W per-unit cap, 120 cycles: THE TWO ARMS ARE
      IDENTICAL ON ALL 120 in grid, site target, every share and every measured
      watt. Both saturated-freeze on 116 of them, both hold |grid error| over
      300 W on all 120 and settle at 1200 W, both read circulating 0.0 W. The
      predicate's inputs do not differ, so no threshold on them can differ. And
      "a cold pack at its floor must not alarm" is the card's own AC 2.

  FALSE NEGATIVE  the standing grid error is what a HEALTHY SIBLING ERASES.
      Load 800 W, same config, B wedged: over the last 30 of 200 cycles the loop
      is frozen on 30 of 30 while the worst |grid error| is 30 W, with B standing
      at +770 W and delivering 0 W. Any X above 30 W is silent for the whole run
      on the exact fault the card describes.

WHAT REPLACES IT. Per unit, for a discharge share, `share - measured`; readable
because of a reduction that only exists at N>=2:

    a unit is named while it is short by more than `saturation_w` with NO
    ACCOUNT for it, and the units in that state are a PROPER SUBSET of the units
    asked to discharge.

THE ACCOUNT keeps the cold pack out and is the only thing that can: the two
cases are identical in the power domain, so the discriminator has to be a
non-power fact, and there is exactly one - the pack's own SoC against its own
`bms_soc_floor`, asked through `peakguard.discharge_permitted()` rather than
transcribed. ⚠️ `bms_soc_floor` ALONE, not `pack_floor_pct()`'s conjunction with
`peak_soc_floor`: that floor bounds a money-saving discharge only and using it
would explain away a wedged unit anywhere between the two.

THE PROPER SUBSET keeps a whole-site cause out - a derate this add-on cannot see
hits every unit; one box that stopped listening does not - and it is what makes
this INERT AT N=1, by algebra rather than by a roster guard.

IT REPORTS. IT DOES NOT ACT, and the strongest argument is for acting. Dropping
the wedged unit from `live` genuinely recovers a site the shipped path does not:
at load 1500 W, kept in the split the site settles at 800 W with a 700 W error
and NEVER comes inside 100 W in 150 cycles (the freeze pins the target, so the
sibling's SHARE never grows); dropped, it delivers 1500 W from cycle 14. What
refuses it is that the only re-allocation this add-on can express is
all-or-nothing: a unit derated to 50 % is short by more than saturation_w with
nothing to explain it, so this detector names it too, and at load 3000 W
dropping it leaves the site delivering 2000 W against 2400 W kept - 400 W WORSE.
A partial re-allocation is what would make acting safe and the allocator cannot
express it. That is a card.

control.py is NOT MODIFIED. The freeze shapes the loop; this reports on it.

NUMBERS, MEASURED. The watts side is `Tuning.saturation_w`, read at runtime, so
there is no fourth CFG-03 copy and it cannot drift from the number the control
law itself calls "not following". `delivery_hold_s: 185` comes off 2640
closed-loop two-inverter runs in which nothing is faulty (6 gains x 5 slews over
the whole schema range, across load reversals, a flapping load and ASYMMETRIC
SPLITS - a family SAFETY-30's campaign did not have and the one that dominates
here) plus 1890 runs at a roster of ONE as the control:

    threshold   reversals   flapping   weighted   N=1 control
     * 500 W      20.0 s      0.0 s      30.0 s      0.0 s

The N=1 column is 0.0 s at EVERY threshold in all 1890 runs, and the flapping
column - the family that defeated SAFETY-30's site window - is zero too, because
a common stimulus makes both units short at once and the subset stops being
proper. ⚠️ The curve is NOT monotone (55.0 s at 250 W against 40.0 s at 100 W):
lowering the threshold can turn a proper subset into the whole roster and BREAK
the run.

⚠️ THE MARGIN IS MEASURED, NOT FELT, BECAUSE INVERTER B DOES NOT PHYSICALLY
EXIST. `plantsim.INVERTER_B` is A COPIED, `measured=False`, so every two-inverter
figure above is two copies of A. Sweeping a different second unit: the worst
legitimate episode is insensitive to B's RAMP (30.0 s at half A's) and scales
with its LAG - 45.0 s at twice A's measured 10 s, 90.0 s at four times it.
185 s is 6.2x the measured worst, 2.06x the four-times-slower case, 6.2x
LINK_STALE_S and 4.9x inside the 900 s quarter. Deliberately not 180, which is
SAFETY-02's site hold.

SAFETY-34. `unit/<name>/delivery_tripped` in the store, one notification id per
unit, re-raised on the first cycle of every process, cleared by the Start press.
No flat mirror: a rollback lands on a version that drives one actuator, where
this check is inert.

⚠️ SCHEMA CHANGE - `delivery_hold_s` joins options: and schema:, so this needs a
version bump before it ships. Additive and defaulted, so an existing options blob
stays valid.

STATED GAPS: charge shares are not graded (no configured charge ceiling exists,
so a constant-voltage taper cannot be explained and arming it would fire on every
maintenance charge); every unit wedged at once is not caught (the subset is not
proper and no instrument here separates that from a plant that cannot).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BwRLw7eKYj2byVdwB6kbjU
2026-09-06 19:25:45 +02:00

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:

  1. ESP32 watchdog — no fresh setpoint for ~30 s → command 0 W, and keep commanding it.
  2. Wind-down before firmware updates — 0 W written before the update starts.
  3. 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.
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