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
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.