admin
4601682815
SAFETY-07 could command a discharge to hold a billed quarter down and nothing below it consulted the state of charge - the BMS was the sole energy backstop. decide() now takes soc and soc_floor, and discharge_permitted() is the one place the question is answered: public, no default arguments, and consulted only AFTER a forced discharge is actually being asked for. The denied action is a 0 W floor - one-directional, forbids charging, structurally cannot cap the discharge the loop is already doing. Reviewed independently. The trade-off is ruled honest and was made a check rather than a footnote: on a pack deliberately sized so the floor must bind, the worst quarter goes 4338 -> 5030 W while end SoC goes 9.6 -> 20.0 % and cycles pinned at the BMS cut-out go 1227 -> 0. Reproduced on the reviewer's own replay, including the 304.2 Wh withheld against 292.8 Wh between the two floors - half a cycle at the rail apart, so the floor is doing the arithmetic it claims. The guard's central guarantee was re-derived across 19,800 combinations of load x elapsed x battery x SoC x floor: 0 negative floors, 0 claims with hi other than +inf, 0 decisions both floor-limited and saturated, 0 arbiter resolutions lowered or contradicted. Rule 8's <= is right: at equality the EMS floor could never be the thing that stops the discharge. Eleven author mutations plus nine reviewer ones, all red under python -B with a purged __pycache__ and real byte deltas. One survivor is an equivalent mutant and provably so: a float(soc or 100) defaulting above the call site is dead code, because a Controller with no SoC never reaches decide() at all - inputs_ok is False and cycle() stops at the safety claim first. That property is now asserted on the service call, replacing an assertion whose sentence was wider than its check. Merged after two rebases. The second one broke a grader neither card could have seen alone: test_peakguard graded the FIRST .decide( in main.py and required exactly one, which stopped being true when OPT-04 added arbitrage.decide(). It failed loudly rather than grading the wrong call. Fixed by selecting peakguard.decide by qualified name and requiring exactly one of that, verified still red on a decoy and on the maintenance_soc_floor swap. Follow-ups filed as SAFETY-27, not addressed here: arbitrage_soc_floor has no rule-8 twin against bms_soc_floor, and this card's own 'revisit if a third floor appears' trigger has fired.
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.