Upgrade to 12000xp of a 18 year old home and its solar backup system, powered by 4400 watt Magnum, 2800 watts of PV and a set of 2V lead acid

Interesting setup — 18 years on lead acid is genuinely impressive if they've been looked after properly. Most people trash theirs within a decade through dodgy charging profiles.

That Magnum inverter is a beast though. 4400W from a 4-wire system is no joke. Curious how the 2800W of PV has held up over that time — I'd expect some noticeable degradation by now, probably sitting at 75-80% output if they've been lucky. Anyone got real figures from similarly aged panels?

My own cabin runs Victron kit with Fogstar lithium cells, so I'm clearly not the one to lecture on "staying the course" with lead acid 😅 But I do respect the old 2V cell approach — those big stationary cells done right will outlast most of us.

Few things I'd want to know about this upgrade:

• Are the 2V cells being replaced or just the inverter/charge setup?
• What's driving the upgrade — capacity, reliability, or just the thing finally giving up the ghost?
• Any plans to add more PV while they're at it?

The 12000XP is a serious step up in capability. If the existing battery bank is still healthy, it'd be a shame to swap it out just for the sake of it. Lead acid gets a bad rap on here but a well-maintained 2V string is still pretty formidable.

Would love to see before/after figures on charging efficiency and resting voltages. These real-world long-term case studies are genuinely useful — beats the usual "I've had my system for 6 months and it's great!" posts we get every other week.

@Curly38 the Magnum kit is solid for North American installs but you'd rarely see it crop up over here — Victron dominates that space in the UK market almost completely now, and honestly the ecosystem integration justifies it.

The 2V cell banks are the interesting bit for me though. Running individual 2V cells means you can actually replace single failing units rather than binning an entire string — which is probably why they've stretched 18 years out of them. Most folk on narrowboats or similar setups buying 12V leisure batteries in bulk will never see that kind of longevity.

Worth noting that 2800W of PV against a 4400W inverter is a fairly modest array ratio — curious whether they're grid-tied as primary and the solar genuinely is backup-only, or if the PV was just never expanded after original install.

@PanelEwan aye, Victron's basically colonised every UK van and narrowboat going — my own Multiplus hasn't given me a moment's grief, unlike my knees.

@Curly38 those 2V cells are the real story here for me — proper industrial kit that most domestic installers wouldn't even consider. The individual cell monitoring must have been key to keeping them healthy this long. Eighteen years suggests someone's been religiously equalising and checking specific gravity rather than just plugging in and hoping for the best.

@RetiredNurse49 @PanelEwan Victron's dominance here is well earned but I do wonder if we're sometimes a bit quick to dismiss alternatives. That said, the GX ecosystem and the sheer volume of UK installers who know it inside out does make it the sensible choice for most people.

Curious what the 12000XP upgrade actually entails — are they replacing the inverter, the bank, or both? At 18 years the PV modules might actually be the component most worth scrutinising now.

@DaiCole agreed on the 2V cells — been looking into a proper 2V bank myself as the next step up from my current Fogstar lithium setup. The lifetime cost argument is compelling when you're talking 18+ years of service.

Quick question for the thread though — does anyone know what monitoring they'd have been using to maintain those cells properly over nearly two decades? I imagine without decent SOC tracking and regular equalisation logs you'd have no idea which cells were drifting. Is that where most lead acid banks fail — the monitoring side rather than the chemistry itself?