Solax Cloud: inverter_vpp_mode/self_consume/charge_or_discharge_mode fails with status 5 every cycle (battery won't discharge)

[andyhollis]

Summary

On a Solax X1-Hybrid-G4 controlled via the Solax Cloud API, Predbat sends two commands each control cycle. The first (batch_set_spontaneity_self_use) succeeds, but the second (inverter_vpp_mode/self_consume/charge_or_discharge_mode) fails with status 5 on every cycle. The net effect is that the battery does not discharge to cover house load — the house is supplied from the grid even with the battery at 94–99% SoC. The failure is not visible in the SolaxCloud app UI (the VPP/self-consume control path isn't surfaced there), which made it hard to diagnose.

Environment

• Predbat version: v8.42.1 (also observed on v8.42.4 / v8.42.5)
• Install type: Docker standalone (nipar44/predbat_addon:latest)
• Inverter: Solax X1-Hybrid-G4, 6.0 kW, ARM/MDSP firmware as reported by SolaxCloud (MDSP 1.36)
• Battery: 2× T58 V2, ~11.6 kWh nominal
• Control path: Solax Cloud API (v2)
• Mode when observed: Monitor (read-only off) and also persists outside monitor

Observed behaviour

Battery at 94–99% SoC, house load ~640 W, solar negligible (overnight/dawn). Battery power = 0 W / not discharging; grid imports the full house load. SolaxCloud shows "Normal / Self Use" with no visible idle window.

The failing command (from predbat.log)

Each cycle, two commands are issued:

1. Succeeds (status 4):

SolaX API: Plant ... Applying self consume mode
batch_set_spontaneity_self_use  {snList:[H4602AI...], minSoc:10, chargeUpperSoc:100,
  chargeFromGridEnable:0, chargeStartTimePeriod1:'00:00', chargeEndTimePeriod1:'00:00',
  dischargeStartTimePeriod1:'00:00', dischargeEndTimePeriod1:'23:59', ...}
-> status 4  (Command execution succeeded)

2. Fails (status 5), every cycle:

inverter_vpp_mode/self_consume/charge_or_discharge_mode
  {snList:[H4602AI...], timeOfDuration:43200, nextMotion:161, businessType:1}
-> query_request_result response {'code':10000,'result':[{'sn':'H4602AI...','status':5}]}
-> SolaX API: Command execution failed with status 5 : Command issuance succeeded for requestId ...
-> SolaX API: Applied controls for plant ...

So the self-use work mode sets fine, but the VPP charge_or_discharge_mode (the call that actually governs charge/discharge/idle behaviour) is rejected with status 5 on every attempt.

Questions / suspected causes

1. Does the Solax Cloud account/inverter need VPP mode or a specific API access level enabled for inverter_vpp_mode/self_consume/charge_or_discharge_mode to be accepted? The basic batch_set_spontaneity_self_use works, but the VPP call does not.
2. Is nextMotion: 161 valid for the X1-Hybrid-G4 on this firmware, or is a different value/endpoint expected?
3. Is status 5 a known "rejected/unsupported" response for this command on this model, and is there a fallback path Predbat should use when the VPP command fails?

Notes

• The reserve figures in the log read oddly vs. the configured 10% (min reserve 0.46% / current reserve 1.15%, Reserve min: 10%), possibly unrelated but flagging in case.
• A separate first-run crash is also present (pv_calibration TypeError: NoneType - NoneType at solcast.py:943, called unconditionally at solcast.py:1369 even with metric_pv_calibration_enable: False) — will raise separately if not already known.

What I've ruled out

• Inverter work mode: confirmed Self Use, Min SoC 10%, Charge-from-grid disabled
• Discharge time window: Allowed Disc Period 00:00–23:59 (discharge permitted all day)
• Max Discharging Current: 30 A (not zero)
• Battery SoC well above reserve (94–99% vs 10%)

All inverter-side settings permit discharge; the only failing element is the VPP charge_or_discharge_mode API call returning status 5.