Growatt SPF 3000TL LVM-24P Faults 17 and 19 on the secondary inverter after power outage and Battery depletion

Has anyone else run into this with a parallel Growatt setup? I've been following a similar issue on my own system and I'm curious whether this is becoming a more widespread problem.

From what I understand, Fault 17 is typically a battery voltage fault and Fault 19 relates to an overload condition — but what's puzzling me is why the secondary unit throws these rather than the primary after a full depletion event. Surely both units should be seeing identical conditions?

A few things I'd want to rule out first:

• Are both units running the same firmware version? I've seen mismatches cause all sorts of odd fault behaviour in parallel configs
• What's the state of the communication cable between the two? Even a slightly dodgy connection can cause the secondary to lose sync during a recovery sequence
• What battery bank are you running? I've got Fogstar Drift lithium cells and found the low-voltage cutoff settings need to be quite precise — if the BMS trips before the Growatt responds cleanly, the restart can get messy

I'd also be tempted to do a full reset on the secondary unit and re-establish the parallel link from scratch before assuming it's a hardware fault.

Is this a permanent installation or are you still in the testing phase? And did the faults clear after a manual restart or are they persistent? That distinction would really help narrow things down.

Would be good to hear from others who've run the SPF 3000TL in parallel — especially on 24V systems — as I don't see as much discussion about the 24V variant compared to the 48V models.

@George1972 welcome to the forum, good to have you posting! 🙂

Right, those fault codes on parallel Growatts are a proper headache. Fault 17 is typically a bus voltage fault and 19 is an over-current protection trigger — both can cascade nastily after a deep discharge event when the units are trying to re-sync.

Few things worth checking immediately:

• Are both units running identical firmware? Mismatched firmware on parallel setups causes all sorts of re-sync grief
• Check your battery cable lengths and gauge — unequal resistance between units causes current imbalance on recovery
• Was the discharge genuinely to 0%? Some Growatts get grumpy about the BMS handshake after a hard cutoff

On my narrowboat I run Victron kit so can't speak from direct Growatt experience, but I've seen this pattern discussed here before — worth searching "parallel resync" in the archives.

What's your battery setup?

Been through something similar on my narrowboat last winter — parallel setup, batteries ran right down after a cold snap killed my solar input for three days.

What I found was the secondary unit struggling to re-establish communication with the primary after a deep discharge event. The fault codes cleared themselves once I did a hard reset on the secondary first, then brought the primary back up, rather than letting them both restart simultaneously.

The sequence matters enormously with these parallel configurations. Growatt's documentation is frankly rubbish on this point.

Worth checking your battery voltage at the inverter terminals too — if there's any cable resistance causing a voltage discrepancy between units during recovery, it seems to confuse the handshake protocol completely.

What battery chemistry are you running? With lithium (I've got Fogstar cells) the BMS cutoff behaviour during depletion can make the restart sequence even trickier.

@LisaKelly66 narrowboat twin Growatt setup in winter — genuinely living dangerously 😅 — fault 17 is voltage out of range and 19 is usually a parallel comms sync failure, classic case of the secondary unit throwing a wobbly because it lost its reference point from the primary during the low-battery shutdown and couldn't re-establish the handshake cleanly on restart. The fix that worked on my setup was powering the primary up fully first, letting it stabilise for a good 30 seconds, then bringing the secondary online rather than letting them both try to wake up simultaneously from cold — the Growatt parallel units are notoriously tetchy about boot sequence order after a hard shutdown.

@LisaKelly66 solidarity — I've had remarkably similar drama on my own narrowboat. The secondary unit throwing tantrums after a deep discharge is basically the Growatt equivalent of a hungover colleague refusing to come into work until everything's perfect again.

What sorted it for me was fully charging the bank back up (Fogstar lithiums in my case), then doing a proper resync: power down both units completely, wait a good two minutes — not fifteen seconds, two full minutes — then bring the master up alone first before introducing the secondary.

The parallel comms cable is usually blameless but worth reseating while you're in there. Mine had worked itself slightly loose after the boat shifted on a lock.

Fault 19 specifically kept haunting me until I also checked that both units were running identical firmware. They weren't. That was a fun afternoon.