glenn schrooyenandClaude Opus 5
2d570d84ce
The reviewer's finding was correct and the shape of it matters: everything the
first cut graded was in peakguard.py, and grading the module is not the same as
grading the guard. Three one-line changes to main.py's CALL SITE left all twelve
suites green while a default install parked at 0 W in the quarter that sets the
month's bill.
B2 was the serious one. My own comment described that defect - "that entity is
optional and empty on a default install, so until now the suspension could not
fire on the site that needed it" - and nothing could regress it. A comment that
documents a fix nobody can test is the same shape as a corrected comment nobody
tests, which this project has already been caught by once.
WHAT CHANGED
The suppression conjunction moved out of main.py and into
peakguard.shaping_suspended(), for the reason watchdog.loop_is_following() and
freeze.looks_frozen() live where they do: the check that grades a safety
predicate must assert on THE SHIPPED EXPRESSION, not on a transcription that can
drift apart from it in silence. Its docstring carries both terms and why neither
is sufficient alone. main.py's call site now says READ THAT FUNCTION FIRST, and
records that a reviewer mutated it back to its historical broken form with every
suite staying green.
test_peakguard.py part 7 gains a section that EXECUTES the three mutations
rather than describing them. Each one is put in place on the shipped module and
the REAL Controller.cycle() is driven with it, on the dangerous fixture: a
default install (no peak_forecast_entity, so peak_fc is None and peak_at_risk is
False forever) with maintenance in its CHARGE phase, so a P_MAINT_SHAPE `hi <= 0`
limit is live, and the guard genuinely engaged on the measurement. That the
mutations are monkeypatched onto the shipped module is itself load-bearing: if
main.py inlined either expression again the patch would do nothing and these
checks would pass vacuously.
SHIPPED suspended=True loop -> 1498 W, limited by peak +1497.8 W
B1 suspended=False CONTRADICTION between limits 0.0 W
B2 suspended=False CONTRADICTION between limits 0.0 W
B2b (forecast term dropped instead) - caught by its own check
B3 is graded three ways, because the single-cycle form is only INFLATED and the
failure is what happens on the next cycle:
* the value main.py actually hands decide() is recorded off the real call, with
the measured battery at 0 W and the command standing at +3000 W;
* the one-cycle difference is asserted to be exactly the standing command - the
whole defect in one line, watts that were asked for and never arrived counted
as if they had;
* both forms are then run forward against the REAL controller's own projection
with an inverter that never follows:
intent-sized floor 4482 5000 5000 5000 ... SATURATED at cycle 2
delivered-power floor 1482 1482 1482 1482 ... stationary
* and the call site is graded on parsed syntax, so a rename cannot quietly
reintroduce it: `decide(batt_w=...)` must unparse to `self.batt`.
SAFETY-24 is now named in peakguard.py, in its own section, with the number that
makes it real - 878 Wh of forced discharge on the 2026-08-20 replay - and the
statement that this must not go to a client install before that ticket lands. A
ticket nobody can find from the code is a ticket nobody reads before shipping.
RED AND GREEN
Fifteen mutations run against the shipped modules, each reverted after: the six
new wiring ones (B1, B2, B2b, B3, B3b, and deleting the SAFETY-24 pointer) and
the eight from the first round, re-run to confirm they still bite. All fifteen
turn test_peakguard.py red. Full suite green, test_price.py and TARIFF-03's
included.
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.