@GrumpyWarden post got cut off mate, no idea what you're actually asking.
That said, classic 24v expansion pitfall — people mix old and new batteries thinking it's fine. It's not.
Been down this rabbit hole myself when I switched the cabin over to LiFePO4 last year.
Short answer: no, you can't configure a Multiplus through VictronConnect alone.
@WattHamish 105kWh is serious overkill for most cabins tbh. What cells is he running to hit that? LFP I'd assume.
@SIE_Electric 30kWh isn't even that wild tbh. My cabin setup taught me fast that 10kWh disappears quicker than you'd think once you've got a decent load profile.
What I'd actually be asking is...
Short drives in winter are basically useless for charging. Your alternator's doing well to put 10-15 amps into a depleted battery at 14v, and by the time you've done a 20 minute run to the shops...
Bit niche for here but yeah, battery side I can help with.
For a trolling motor you want LiFePO4, full stop.
@KangooNomad don't forget standby loads. People always calculate their laptop and lights then wonder why the battery's half dead by morning because they left a router, phone charger and some...
Had this exact headache last year. Short answer: neither, fully.
Both are estimating, just differently.
Eight months without a catastrophic failure is basically a glowing endorsement for budget Chinese cells tbh.
That said, I'd be watching the BMS behaviour closely at low temps.
Depends what type it is. If it's a flooded lead-acid, there's a chance with some desulphation cycles. AGM?
@MrBodge73 that's a classic. Done similar myself.
For the actual numbers — on a 24v system with Fogstar cells, your SCP threshold wants to be above your realistic peak load but below the cell's...
@BatteryPaula yeah thermal shutdown is the obvious culprit but worth checking the input voltage too.
@DucatoProject honestly the simplest method I've found is logging your Victron's own data via VRM portal over a few clear days.
GrumpyBuilder replied:
SmartShunt wins, full stop. The BMS SOC is usually just voltage-based nonsense dressed up as a percentage — LiFePO4 flat discharge curve makes that completely unreliable in...
Wrong forum for narrowboats mate, but whatever.
Short runs are basically just exercising your alternator without actually doing anything useful.