Sezibwa SRNE inverter: proven behaviour register
Copy of the register kept in the microgrid-gateway repo:
docs/sezibwa-srne-proven-behaviour.md. The repo copy is the master; this page is refreshed when it changes. Owner: Hillary (with Claude). Reviewer: Aaron.
Site: Sezibwa Rentals, gateway gw-pi2. Inverter: SRNE ASP48120SH3, with 1 battery and 8 × 600 W panels.
This register lists what we have seen happen on this unit, with the date and the evidence. A control rule may depend only on rows under Proven. Anything under Not proven needs a planned test, with a clear pass and fail, before a rule relies on it.
Rules for keeping it
- Add a row only when the data shows it, and cite the evidence (Influx field and time, driver log line, or register read).
- A result counts only if no other cause can explain it. On 11 Nov the charge stopped near 50% because the 00:40 window ended, not because of E03B. That case did not separate the two causes.
- When a rule changes, its PR lists the rows it relies on.
Times are EAT (Africa/Kampala).
Proven
| # | Behaviour | Date | Evidence |
|---|---|---|---|
| P1 | The output mode changes only when E204 is written; the manual's implied mode is not applied | 3 Nov | Stayed SUB until E204=2 was written (v29) |
| P2 | SBU runs the houses from sun plus battery, with the grid unused, when SoC is at or above E020 (after a drop to E01F the unit stays on the line until SoC reaches E020, see P4/P5). Every SBU observation so far was at or above E020; below it is N5 | 4–5 Nov, 12 Nov 16:00 | MachineState 3, meter shows no grid draw |
| P3 | In a grid cut the unit runs on battery, and stays on battery after the grid returns until the battery reaches E01F | 6 Nov 00:37, 11 Nov | SoC timeline; stayed in state 3 with the grid at 230 V |
| P4 | At E01F with the grid present, it moves the houses to the grid (state 2) | 11 Nov 23:05, 12 Nov 22:15 | MachineState 2 at 10–12% SoC |
| P5 | With E20F = 2 (hybrid), the grid charges the battery at about 120 A at any hour while the unit is on the line | 11 Nov 23:05–23:50 (to E020 = 50%); 12 Nov 14:00–16:00 (SUB, solar near 0, 116 A) | BatteryCurrent −117 to −120 A, solar about 0 |
| P6 | The timed charge (E00E = 1, window E026/E027) charges from the grid at about 120 A, about 1% SoC per minute | 13 Nov 00:05–01:50 | SoC 11 → 99 % |
| P7 | E03B (window stop SoC) does not end the timed charge | 13 Nov | E03B = 50, charged to 99% inside a 00:00–06:00 window |
| P8 | The solar panels keep charging while the unit is on battery during a cut | 6 Nov 10:22 | PV 1.4–2.0 kW, battery charging at +0.7–1.3 kW |
| P9 | In SUB with the battery near full, the solar input is shut down (PV voltage 0) | 10 Nov (94%) | Pv1Voltage 0 at midday |
| P10 | The panels can reach about 98% of nameplate (4.7 kW of 4.8 kWp), so the panels and wiring are fine | 11 Nov 12:50 | charger0/Pv1Power max |
| P11 | Settings are written only in MachineState 2, except the ModeSchedule SUB write, which is allowed in state 3 when the grid is present on all phases (#45, gridPresentMinVoltage 180), and the E20F safe value (#48, not yet deployed) |
design, logs, Influx | Writes stayed queued all day on 11 Nov while the grid was off. State-3 SUB write: 12 Nov 14:00 EAT, MachineState 3 / OutputPriority 2 at 13:40–14:00, then state 2 / priority 3 at 14:00–14:20 with the grid at 234 V (Influx, 20-min means; driver log lost when the container was recreated on 13 Nov) |
| P12 | A charge-window change can stall after the disarm or window write; a controller restart while in state 2 completes it | 11 Nov 18:11, 12 Nov 14:00 | Log shows the disarm or window write with no follow-up; after the 14:31 restart, enable = 1 at 14:34 |
| P13 | ModeSchedule times are Kampala local time, not UTC | 10 Nov | v35b fix |
| P14 | At E01F on the line, the unit sometimes does not grid-charge (stays at about 0 A) | 12 Nov 22:15–24:00 | SoC 11%, BatteryCurrent about 0, state 2. Compare with P5; see N2 |
Not proven (test before relying on it)
| # | Question | Why it matters | Planned test |
|---|---|---|---|
| N1 | Does E20F = 3 (PV only) stop all grid charging, including the timed window? Is E20F re-read during an active timer? | D138 (openems #48) depends on it | First night after #48: log E20F, the window and BatteryCurrent from 23:50 to 00:30 and at any E01F transfer. Pass: no grid charge outside 00:00–06:00, and the night charge runs |
| N2 | Why did P5 happen on 11 Nov but not on 12 Nov (P14)? | Predicting evening grid buying | Compare the registers (E20F, E205, E020, OutputPriority) logged on both nights |
| N3 | Cause of the 5 Nov solar stall (PV fell from 2.8 kW to under 0.7 kW on the switch to battery) | Daytime SBU switching | Watch every daytime SBU switch for a PV drop greater than 50% |
| N5 | Does an SBU write below E020 move the unit to battery, or does it stay on the line until SoC reaches E020? | #114 (daytime SBU from 30%) depends on it | After the first daytime SBU write below E020, watch MachineState for 5 minutes. Pass: state 3 within a minute |
| N4 | Real daily solar compared with PVGIS (about 18 kWh/day expected) | The business case | One full month of charger0/PvEnergyToday against PVGIS for the same days |
Change log
- 13 Nov 2026: register created from 3–13 Nov site data.
- 13 Nov 2026 (Aaron's review): P2 limited to SoC at or above E020; P11 lists the state-3 exceptions, with evidence; N5 added.
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