glenn schrooyenandClaude Opus 5
e709554857
SAFETY-07 can command a discharge to hold a billed quarter down, and nothing below it consulted the state of charge. On the 2026-08-20 replay it asks for 878 Wh in a day. Relying on the BMS is not absurd - it is a real floor and it works - but it is the pack's protection rather than the operator's, and a month of aggressive quarters leaves the battery repeatedly at that cut-out with no EMS-side record of why. The first symptom is a pack never available when wanted, which is indistinguishable from the SoC drift MAINT-01 exists to correct. decide() now takes soc and soc_floor, both required and neither defaulted, and discharge_permitted() is the one place the question is answered. Above the floor nothing changes. At or below it the guard files a 0 W floor instead of a sized one - one-directional, so charging stays blocked and no discharge is capped - and reports floor_limited with the reason it bound. It is not a trip: every stop in 11.2's table still outranks the claim, and the floor is never negative, so 9.1's asymmetry survives as a property of the object (0 negative floors over 1296 swept combinations, SoC included). The SoC is graded only after `wanted > 0` is established, so it is never evaluated where it governs nothing. An unreadable SoC is floor-limited, not a full battery - a full battery is exactly the value that would disarm the floor, and this project shipped that defaulting once already. Failing to shave is not silent: one notification per episode (goodwe_peak_soc_floor), distinct from the saturation alarm because the two ask for opposite operator actions, plus its own status row and an action-log line. Verified by replay. The 2026-08-20 capture is driven against a modelled pack sized from the day's own measured appetite, so it genuinely exhausts: without the floor it reaches the BMS cut-out and holds there for 1227 guard cycles; with it the pack stops at 20.0 % and never touches the BMS. The energy withheld equals the energy between the two floors to within one cycle at the rail. The honest half is reported too - the worst quarter goes 4338 W -> 5030 W, because a floor-limited guard shaves less on purpose. Two new options, mirrored once in peakguard.PEAK_OPTION_DEFAULTS (TARIFF-02's pattern), imported by validate.py and main.py rather than typed as literals and pinned to config.yaml by a check that reads the file - so CFG-03 still tracks three places. validate.py rule 8 refuses peak_soc_floor <= bms_soc_floor at startup, in CFG-01/MAINT-04's manner. maintenance_soc_floor is deliberately not reused and not renamed: it is a drain target, not a spend limit, and the rename is recorded as a decision to revisit if a third floor appears. Eleven mutations of the shipped source were run against the checks; all eleven go red and there are no survivors. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_015VXjA3LWccN1rJsk3okyPC
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.