2026-04-26 (afternoon) — LVX6048 parallel-mode commissioning

Got the two LVX6048 inverters operationally paralleled, sharing battery charge from the EG4 LP4 v2 bank symmetrically. Several discoveries about the firmware's parallel-state reporting along the way, plus a couple of small patches.

What happened

Firmware parity (main CPU): achieved. Pre-flash main versions were 06303 (unit 1) and 06440 (unit 2). User flashed both to 06306 using the MPP Solar InfiniVMasterCPU_Reflash tool. Active fault 71 ("Parallel version different") cleared.
Slave-CPU firmware: still skewed but benign. Slaves remain 06126 / 06021. The vendor's LVX6048 FW63.06.zip does include a dsp.hex slave bin, but the operational evidence (load-sharing, matched battery V, no faults, master/slave handshake completing) indicates the slave delta is not blocking parallel function on this firmware family. Not flashing the DSPs — filed for the record only.
Battery wiring + commissioning. Both inverters tied to the same 3× EG4 LP4 v2 100 Ah bank (300 Ah at 51.2 V nominal). After fault 83 ("Parallel battery voltage detect different") cleared on first battery-connected boot, both inverters entered MOD 06 and began sharing the charge load (~55 A each, ~110 A combined ≈ 0.37 C).
MCHGC mismatch (100 A vs 60 A) → fixed. Unit 1 was at 100 A — above the PI18 MCHGC setter's 80 A ceiling, so it had to be set via the LCD (Program 02). User dropped unit 1 to 60 A so both match. Confirmed via flash.py compare (12/12 settings match).
Patch (g) tweak — outputformats/hass.py (unrelated to parallel work but lives in the same patch tree). No change here today; the morning's cleanup is in commit f771ec2.
Patch (h) — pi18.py MOD decoder. Inverter started reporting MOD code 06 after batteries connected; the existing decoder only knew 00..05 and crashed (KeyError: '06'). Added "06": "Charge". The "Charge" label is an educated guess based on observed behavior (active charging, no AC out); revisit if it turns up in unrelated states.
parallel_instance_number decoder fixed. The GS/PGS field is the parallel-instance index per the PI18 spec (0 = master, 1+ = slaves), not a 2-value flag — but powermon upstream (and our patch) was decoding it as ["Not valid", "valid"], which made the master appear as "Not valid" in HA. Replaced with an OPTION decoder labeling each index ("instance 0 (master)", "instance 1", ...) in both GS field 27 and PGS field 0. flash.py sync-check updated accordingly: removed the false-positive "GS parallel_instance_number = Not valid" issue, replaced with index-collision and no-master checks.
lvx-resolve-links now auto-runs on USB hot-plug. Added an ACTION=="add" udev rule for vendor 0665 / product 5161 that RUN+=s systemctl --no-block restart lvx-resolve-links.service powermon.service powermon2.service. Powermon's Requires= / After= already serialize the chain. Added a retry loop to the resolver script (poll up to ~10 s for both expected serials) so a single hidraw appearing slightly before its sibling doesn't leave a symlink missing. Tested via udevadm trigger --action=add --subsystem-match=hidraw: all three services restarted in lock-step and symlinks rewrote cleanly.
Battery profile YAML for the bank. Created lvx-flash/profiles/eg4-lp4-v2.yaml capturing the conservative off-grid LFP policy (USER mode, bulk 56.4 V / float 54.0 V, cutoff 48.0 V, stop-charge 54.0 V). Live state already matches — applying would be a no-op. Kept as the canonical record of the chosen policy.
Sanity dumps — 2026-04-26-lvx6048_{1,2}-dump capture per-unit settings post-commissioning. Useful as a baseline for diff-on-suspect.
Battery side: re-discovered that EG4 LP4 v2's inter-pack daisy-chain silences slave packs. User had wired the inter-pack Link-In/Link-Out chain earlier in the day; it elects a master and demotes slaves on their independent RS485 ports. Pulling the chain restored all three packs to MQTT immediately (all reporting 54.62 V agreement). Daemon needed no change. Memorized for next time.

Net effect

Metric	Before	After
Main-CPU firmware	06303 / 06440	06306 / 06306 ✓
Slave-CPU firmware	06126 / 06021	unchanged (benign)
Active fault 71	yes	cleared
Active fault 83	n/a (no battery)	cleared
MCHGC delta	100 A vs 60 A	60 A / 60 A ✓
Settings parity	mismatch	12/12 match
Charge-current sharing	n/a	55 A / 57 A symmetric
Battery V agreement	n/a	55.1 V / 55.1 V identical
`parallel_instance_number`	"Not valid" / "valid" (master mislabeled)	"instance 0 (master)" / "instance 1"
MOD 06 crash on sync-check	yes	fixed
Hot-plug symlink recovery	manual `systemctl restart`	automatic via udev `RUN+=`

Files touched

M  LVX6048/powermon-patches/pi18.py            (MOD 06 -> "Charge"; parallel_instance_number decoder fix)
M  LVX6048/lvx-flash/flash.py                  (parallel_instance_number index semantics; new sync-check rules)
M  LVX6048/bin/lvx-resolve-links               (retry loop for hot-plug race)
M  LVX6048/etc/udev/rules.d/99-lvx6048.rules   (ACTION=="add" RUN+= cascade)
A  LVX6048/2026-04-26-lvx6048_1-dump           (post-commissioning baseline)
A  LVX6048/2026-04-26-lvx6048_2-dump           (post-commissioning baseline)
A  LVX6048/lvx-flash/profiles/eg4-lp4-v2.yaml  (canonical battery profile)
A  LVX6048/2026-04-26-parallel.md              (this file)

How to verify

sudo systemctl stop powermon.service powermon2.service
sudo systemctl restart lvx-resolve-links.service   # always run after inverter power-cycle
/home/noise/solar/LVX6048/lvx-flash/flash.py sync-check \
    --device-a /dev/lvx6048-1 --device-b /dev/lvx6048-2
sudo systemctl start powermon.service powermon2.service

Pass criteria post-commissioning:

main fw 06306 on both
mode=06 (Charge) or mode=03 (Battery) or mode=05 (Hybrid) — i.e. healthy operating modes, no 04 (Fault)
fault=No fault on both
both parallel_* values present (one as master/0, one as slave/1)
battery V agreement within ~0.2 V
charge currents within ~5 A symmetric (when both are charging)

Loose ends / next pass

update LVX6048/README.md "Next steps" section to reflect that parallel commissioning + decoder + hot-plug fixes are done, and the slave-firmware delta is intentionally unrepaired (benign)
(optional) verify MOD 06 label by observing in different states
(optional) decode remaining PGS fields now that values are meaningful
(optional, longer horizon) closed-loop BMS comms via the dedicated pack→inverter CAN port; defer until open-loop has been stable for a week and we can baseline SoC accuracy

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