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Hardware: EG4 18kPV (18KPV-12LV), firmware FAAB-2727, with a 3rd-party Docan 48 kWh LiFePO₄ in closed-loop (comms confirmed — pack SOC matches the inverter, BMS Charge/Discharge = Allowed).
I logged read-only Modbus telemetry every 15 seconds and ran controlled A/B tests, reading each setting back from the holding registers to confirm it applied. Two behaviors don't match the documentation/UI:
1) "Time + SOC" mode ignores the Stop-SOC target.
Expected: charge during the window and only up to the Stop-SOC, then stop.
Observed: it charges the entire window regardless of SOC, overshooting to full.
- Test A: Stop SOC set to 85% at 14:09 — 16 minutes BEFORE the 14:25 window opened (ruling out "changed mid-window"). Battery grid-charged straight through 85% to 99% by the window's end. Net solar (PV − load) was negative after ~15:15, so the whole 56% → 99% climb was grid charging.
- Test B (clean retest): Time+SOC, Stop 45%, set before the window, wide band. Charged straight through 45% → 47%+ at full rate, with no throttle at the target.
2) AC Charge Power (kW) setpoint is ignored.
- Set to 3 kW → charged ~8.6 kW.
- Set to 10 kW → charged ~8.4 kW.
Identical. Actual rate tracked only the BMS charge-current limit (~150 A at 50% SOC, tapering), never the kW setpoint.
3) For contrast — "SOC"-based mode DOES stop correctly (same battery, same live SOC):
With Based On = SOC, Stop 53%, grid draw went 873 W → 0 exactly at 53% and stayed at 0 even as house load rose. This shows the inverter has correct SOC and can act on it — which points the Time+SOC failure at the charge-control logic, not the battery or its comms.
Questions:
- Is the Time + SOC behavior (1) intended, or a firmware bug? I expected it to stop at the target within the window.
- Is the AC Charge Power (kW) setpoint supposed to cap grid charge current? It appears ignored.
- If (1) is intended, what's the supported way to grid-charge to a target SOC within a time window and then stop? (SOC mode stops at target but ignores the window, risking charging during peak-rate hours.)
Happy to share full 15-second logs, register snapshots, and charts. Anyone else on FAAB-2727 seeing the same?
Posted : July 5, 2026 9:16 pm
Topic starter
Follow-up / clarification (please disregard my 85% example):
Since posting I identified a SEPARATE issue with my battery's SOC gauge — the pack's
reported State of Charge freezes near 80% and then jumps straight to ~100%, skipping
81–99%. (3rd-party Docan/JBD-type BMS; reported to the battery vendor separately.)
That means my Stop-85% example is NOT clean evidence — the inverter never actually
"saw" 85%. Please set that one aside.
The core finding is unaffected and rests on gauge-independent tests: with Stop SOC set
to 45% — a mid-range value the gauge reports accurately (43 → 45 → 46 → 47 in order) —
"Time + SOC" grid-charged straight through 45% at full rate (~11 kW) with no throttle
and no stop. A Stop-35% test behaved identically. So Time + SOC ignores the Stop-SOC
target regardless of any gauge behavior.
Findings 2 (AC Charge Power setpoint ignored) and 3 (SOC mode stops cleanly at 53%)
are also independent of the gauge. Happy to share the 15-second logs and a chart.
Posted : July 6, 2026 8:36 pm
