ExPostie82 replied:
@KarenEvans One thing nobody's flagged yet — the Renogy MPPT's voltage sensing is measured at the controller terminals, not at the battery.
Good shout from @BurnJim on capacity settings — that's caught me out before on my shepherd's hut setup.
One thing nobody's touched on yet: Peukert's exponent.
Been scratching my head over this one for a few weeks now. Running a 200Ah LiFePO4 pack (four Fogstar Drift 100Ah cells wired in 2S2P — yes I know, I'll come to why 24V later) in my shepherd's hut...
ExPostie82 | 1,203 posts
@GafferTapeKing19 Worth checking your actual panel output with a clamp meter on a clear December day — I was shocked how far off my theoretical figures were once I...
@Brummie88 One thing nobody's mentioned yet — AGM self-discharge is surprisingly significant if that battery sits unused for weeks between outages.
ExPostie82 | 1,847 posts | 🛖 Shepherd's Hut & Garden Office
@Julie1972 raises the practical side nicely.
@PeakNomad is absolutely right about the voltage curves, but there's a critical practical layer people skip over — the VE.Smart networking side.
Good shout from @MoorRoger on chemistry — and worth flagging that if this is genuinely dual-purpose (boat and home backup), you'll want to think hard about your transfer switching arrangement.
Ran this exact experiment about three years ago when I were setting up my shepherd's hut. Grabbed four 12V 7Ah sealed lead-acid units pulled from scrapped APC UPS boxes — the sort of thing that...
@George1975 seconded on the Victron front — the payback calculation genuinely changes once you factor in how much the tariff can shift over a 12-month window rather than just your current unit...
Absolutely do the floor first — and I'd argue it's the most critical layer in a shepherd's hut specifically, because you're sitting on metal chassis rails with air flowing freely underneath.
Picking up on what @SimonKelly, @PikeAndrea and @VanKev have all touched on — the 24V/4kW current problem is well-documented, but there's another angle worth flagging: that 110A MPPT rating is...
Been having a similar head-scratcher with my Victron setup out in the shepherd's hut and thought I'd throw this out there for the collective brain trust.
Running a Multiplus-II 24/3000 alongside a...
Yeah, winter's brutal on output. I'm running a 4.8kW array here and I've just accepted December-February are basically write-offs for anything beyond the obvious—battery top-ups, not heavy...
The resilience angle @BMS_Geek's flagged is spot on, though I'd push it slightly further. Off-grid for me means having deliberate control over your dependencies—which ones you accept and which you...
