Split Phase Hybrid Inverter + Low Voltage Battery Compatibility + 1741 SA or SB approval list

Has anyone here gone down the rabbit hole of 1741 SA/SB approval lists when pairing a split phase hybrid with a lower voltage battery bank? I'm currently looking at options for EV charging from a hybrid setup and the compliance side is doing my head in.

From what I can gather, a lot of the inverters that tick the 1741 SB box (for grid interaction) are heavily skewed towards 48V nominal systems, which makes sense for most installs. But I'm wondering whether anyone has managed to get a lower voltage bank — say a 24V Fogstar or similar — working with a split phase hybrid that's on an approved list?

A few questions I'd love some input on:

• Does the 1741 SA/SB approval essentially lock you into specific battery voltage ranges in practice?
• Are there any split phase hybrids that handle lower voltage banks and still meet the interconnection standards?
• How are people handling the EV charging side — are you running a dedicated EVSE off the split phase output or going through the inverter's own charge management?

I've been eyeing the Victron Quattro range but my understanding is the split phase capability there requires a bit of careful configuration, and I'm not sure it sits neatly on the 1741 SB list as standard.

Would love to hear from anyone who's actually navigated the utility approval process with a non-standard battery voltage setup — particularly if you're in a grid-tied scenario. Any real-world experience here would be genuinely useful before I commit to anything.

@Cleggy went down exactly this rabbit hole last year with my cabin setup.

The 1741 SA/SB compliance piece is where a lot of people get unstuck — particularly with split phase hybrids running lower voltage banks (say 24V or 48V nominal). The approved list is very US-grid focused and a lot of the units people try to import don't play nicely with G98/G99 requirements over here anyway, which muddies the water further.

What voltage bank are you working with? And is this grid-tied or off-grid with EV charging purely from stored solar?

For EV charging specifically I've found the Victron Multiplus-II route more predictable — combine it with a proper EVSE controller rather than trying to push it through the hybrid's built-in logic. Less elegant but far fewer headaches.

My Victron MultiPlus-II laughed at me for three weeks before I finally matched the battery bank voltage correctly — don't even get me started on compliance paperwork, that's a whole separate therapy session.

@Cleggy the 1741 SA/SB piece is largely a US grid-tie concern — if you're UK-based you're looking at G98/G99 compliance instead, which is a completely different approval pathway. Worth clarifying which market you're actually in before chasing the wrong certification rabbit hole.

On low-voltage battery compatibility with split-phase hybrids: the problem typically isn't voltage per se, it's the inverter's minimum battery voltage threshold versus your bank's actual resting voltage under load. I ran into this on my narrowboat with a 24V Victron setup — the inverter would trip out during high-draw events because the BMS and inverter weren't communicating properly over VE.Bus.

For EV charging specifically, you're looking at sustained high-current draws that will expose any weak link in the chain fast. What battery chemistry are you running and what's the target charge rate?

@LH_Marine is absolutely right on the regulatory front — worth spelling out exactly why though. 1741 SA/SB governs inverter grid-interaction behaviour under IEEE 1547-2018, which is a US standard. UK grid-tie compliance runs through G98 (≤3.68kW per phase) or G99 (above that threshold, requiring DNO pre-approval). Completely separate certification pathways.

For EV charging from a split-phase hybrid in a UK context, the voltage bank question becomes more interesting. Are you running 48V or looking at higher-voltage LFP stacks? The reason I ask — if you're pushing meaningful EV charge rates (7kW+), your battery C-rate demands get ugly fast on a standard 48V/200Ah bank. Worth sizing the bank around your inverter's peak draw before anything else.

What inverter are you actually considering? That'll narrow down the G99 pre-approval conversation considerably.