`bms_soc_floor` describes A BATTERY, not a site. At two packs of different models the cut-outs differ, and one number for both graded the shallower pack against the deeper one's BMS - so a site with cut-outs of 10 % and 30 % under `peak_soc_floor: 20` STARTED, and the guard would command a forced discharge that pack B's BMS, not the operator's floor, is the thing that stops. That is rule 8's own failure mode, reached through rule 8. Scoped to the card's third bullet, per its PM PROOFREAD: the aggregate anti-windup (DEV-02) and per-instance `achievable_w` (CFG-04) were verified as already shipped and are untouched. * config.yaml: `bms_soc_floor: int(0,50)` REQUIRED per `inverters:` entry. Nothing is inherited; the flat key stays the single-inverter shape's own cut-out. A per-entry DEFAULT was declined - a default is one number for every pack, which is this card's defect - and the decision is recorded. * inverter.py: `Inverter.bms_soc_floor`; an entry that states none gets None, not a borrowed number and not 0.0 (the most permissive value the key has). * peakguard.py: `Pack`, `pack_floor_pct()`, `pack_permissions()`, `binding_soc_floor()`. `discharge_permitted()` is unchanged and is still the one place the question is answered. * validate.py: `unit_bms_floors_indexed()` carries the ROSTER index; rule 8 grades EVERY unit and NAMES the one it refuses. Graded with the offender SECOND and with the same two numbers in the other order. * main.py: `Controller.packs`; `decide(soc_floor=...)` is the per-pack reduction of the same option; the floor-limited notification names the pack that stopped the site. `pack_floor_soc` - the emptiest pack, and its None-on-missing behaviour - is untouched. * tools/supervisor_shape_probe.py: RE-RUN and repaired. The required key broke §C and left §D printing PASS on a refusal about a different key. §D is now an isolated counterfactual over an accepted merged baseline, one key varied, asserting the key name. `all cases passed` on 2026.08.0. Stated rather than hidden: under any config rule 8 accepts the per-pack FLOOR reduces to `peak_soc_floor` for every pack. The reduction is written for `unit_caps_indexed()`'s reason and graded on both sides - 1775 rule-8-valid pairs answer the option, the pair rule 8 refuses answers the cut-out. `peak_soc_floor` is still one number for the site, so the "deeper pack needlessly withheld" half is filed as an open question, not closed. Full 19-file suite green. Twelve source mutations through tools/mutation_run.sh: eleven red, one argued survivor. The battery also found `_flat_bms_floor()` defaulting in two places, each covering for the other. No measurement of inverter B appears anywhere: it does not exist yet. Every second-pack figure is simulated and labelled. 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.