Quattro-II 48/5000 Fault / No AC Output Following Firmware Upgrade v556 to v560

Had a similar scare with my Quattro-II 48/5000 last month — firmware updates via VRM can be a right lottery sometimes.

Mine's running v558 and I've been deliberately holding off on v560 after seeing a couple of mentions of post-upgrade issues across various forums. The setup here feeds a garden office, a cabin, and a 7kW EV charger (yes, simultaneously — it's marginal but it works), so any unexpected AC output loss would be genuinely disruptive.

A few things worth checking if you're affected:

• ESS assistant — upgrades occasionally wipe or corrupt assistant configurations. Re-run the ESS setup via VEConfigure and see if that restores output.
• Grid code settings — v560 may have tightened compliance defaults. Worth verifying your country code is still set correctly (G98/G99 relevant for UK installs).
• BMS communication — if you're on a CAN-bus BMS (I'm using Fogstar Drift cells with a Batrium BMS), check whether the inverter is receiving charge/discharge enable signals post-upgrade. A comms dropout can cause the Quattro to sit silently doing nothing.

Has anyone confirmed whether Victron's changelog for v560 actually documents any changes to AC output behaviour, or is this undocumented? The release notes are frustratingly sparse sometimes.

Would be interested to hear whether a firmware rollback to v556 restores normal operation — theoretically possible via VictronConnect with the right cable, though I've never had to do it myself. Anyone gone that route successfully?

@IslandVanLifer wise move holding at v558 for now. From what I've seen on the Victron Community forums, v560 introduced some changes to the ESS assistant logic that's causing grief specifically with certain BMS comms configurations — particularly anything using CAN-bus rather than VE.Bus BMS.

Worth checking:

• VEConfigure → Assistants tab — verify your ESS assistant hasn't reset to defaults post-upgrade
• Pull the VRM diagnostic logs around the exact timestamp of the fault
• Check dbus-spy on Venus OS if you've got SSH access — look for BMS state transitions

My Quattro-II on the narrowboat threw similar fits after an update last year — turned out the grid code had silently reverted to a non-UK setting (G98 vs G99), which killed AC output entirely. Easy fix but took ages to diagnose.

Fogstar Drift cells or something else on your bank? BMS brand matters a lot here.

Bit of an odd thread to land in for a first post, but welcome to the forum @IslandVanLifer — good to have another Victron user on here.

@ExSquaddie49 makes a fair point about holding firmware. I'd add: always check the Victron Community changelog properly before updating, not just the version number. v560 release notes had some specific caveats around certain BMS communication protocols that caught a few people out.

On my narrowboat setup I've got a Quattro-II running alongside Fogstar Drift cells and I'm very conservative with firmware — I wait at least 4-6 weeks after release before touching anything that's working.

What BMS are you running? That'll likely be relevant to diagnosing the no-AC-output fault.

Worth checking the Victron Community forum before touching v560 — there's a specific thread about ESS assistant conflicts post-update that's been causing grief for a few installs.

My garden office setup runs a Quattro-II 48/5000 alongside Fogstar Drift cells and I've been religiously staying one firmware behind on anything critical since a dodgy MPPT update last spring bricked my charge profile settings temporarily.

@IslandVanLifer — before your next update, export your VEConfigure settings file as a backup. Sounds obvious but it's saved me twice now.

One thing worth ruling out if anyone has already upgraded and is seeing no AC output: check whether the grid code setting got reset. v558 to v560 apparently touches that area and UK installs need G98/G99 correctly set or the unit won't energise the output.

Has anyone actually rolled back from v560 successfully, or is it a one-way street once you've updated? I'm on a Quattro-II 48/5000 myself and the whole situation has me nervous about touching anything firmware-related for a while.

Also wondering — is this purely an ESS assistant issue, or are people seeing problems on straight inverter/charger setups without ESS configured? Mine's not running ESS so trying to work out if I'm even in the firing line here before I accidentally click update one morning half-awake.

@OffGridGuru any idea if Victron have acknowledged the fault officially yet, or is it still just community-level reports at this stage?