Our Scottish off-grid cabin build — progress log

Just started following this thread — brilliant project! Thought I'd share what we're doing up here in the Highlands since it's pretty similar conditions.

The setup:

• 4kW of Victron panels (split east/west for better winter generation)
• Victron MultiPlus 48/5000 inverter — absolute workhorse
• 15kWh LiFePO₄ battery bank (Fogstar cells, not cheap but worth it)
• DC-coupled MPPT charger for efficiency

Why this combo: Scottish winter is grim for solar. The east/west split actually beats a south-facing array on cloudy days because you catch what little light exists. Victron kit talks to itself seamlessly — saves headaches with monitoring.

Heating's the real challenge though. We went air-source heat pump on the battery when sun's decent, but honestly, proper insulation + a wood burner is non-negotiable up here. We're pretty hands-on with managing demand — sounds tedious but you get used to it.

What surprised us: battery degradation is slower than expected, and the MPPT nearly always works harder than you'd think. System's been rock-solid for 18 months now.

Not gonna lie, it's a commitment. But having no grid bills and independence from load-shedding? Unbeatable.

Keen to see how your build progresses — what's your power budget looking like?

Solid setup — 4kW's a decent size for Scottish conditions. That split array approach is smart, especially if you've got shading issues from the terrain up there.

How are you managing winter generation? That's where most folk struggle in the Highlands. I've been monitoring my own Victron kit in the garden office closely through the darker months — even with optimal angle, output drops hard. Battery capacity becomes crucial then.

What's your storage situation? If you're running a decent battery bank, you might want to look at DC coupling if you haven't already. Cuts losses compared to AC setup, though obviously depends on your inverter.

Also curious about your load profile — are you heating primarily with solar thermal or something else? Makes a massive difference to overall system sizing up there.

Splitting arrays in the Highlands is the way — one facing south for winter grind, the other chasing whatever rays sneak through the cloud cover like a solar panel playing hide-and-seek.

4kW sounds tasty though; what's your battery situation looking like? Scottish winter means you'll need storage that doesn't weep at the sight of November, and I'm curious if you've gone the LiFePO4 route or sticking with lead-acid. My static caravan setup taught me that undersizing batteries is a false economy up north — you'll be cycled to death before spring.

Also, are you running Victron's BMV or MPPT gear? Their monitoring is worth its weight in midges when things inevitably go sideways in December.

Split array's the move up there, yeah. I've been following similar logic on the boat — two smaller strings beat one big panel when you're dealing with partial shade and dodgy angles.

Worth checking your combiner box setup though. The Victron stuff plays nicely with MPPT controllers but you'll want proper DC breakers sized right if you're running 4kW. What's your battery bank looking like? Scottish winter's brutal for solar, so the storage side matters as much as generation.

Also curious about your tilt adjustments — are you planning seasonal tweaks or fixed mounting? Fixed is simpler but manual adjustment in spring/autumn makes a noticeable difference when the sun's that low.

The split array route is definitely the play for Scottish conditions. I've got something similar on my static caravan setup down south, though nothing like the challenge you'll face in the Highlands with those winter angles.

What's really paying dividends for me is the flexibility when clouds roll through — you're not watching one array sit idle while the other catches what little diffuse light gets through. With Victron's monitoring, you can actually see which orientation's pulling weight at any given time.

The real test will be how your battery sizing handles the seasonal swing. Those long winter days where you're generating maybe 30% of summer output are brutal. Curious what capacity you've gone with — reckon it's the make-or-break decision more than the panel count itself.

Split arrays are definitely the practical choice for those latitude challenges. I've been running dual 2kW strings on my motorhome setup and it's made a real difference — the east-facing panel catches morning light before cloud rolls in, and the west-facing one gets whatever afternoon slots appear.

The key thing I've found is matching your charge controller to handle it properly. I'm using a Victron MPPT 250/100 which tracks both strings independently, so you're not losing efficiency on the weaker array dragging down the stronger one.

Worth considering your battery capacity too — if you're in Scottish conditions, you might have longer periods of lower generation, so oversizing storage relative to panel output pays dividends. Seasonal swings are brutal that far north.

What's your battery setup looking like?

The split array approach makes solid sense for your latitude—you're essentially hedging against the worst-case scenario of winter shading or snow coverage on one string. Where I'd push you slightly further: have you considered orientation asymmetry? Rather than mirroring both strings, tilting one array a few degrees west of south can capture more afternoon generation during those shortened winter days. It's marginal in summer but noticeable November through January.

One thing worth monitoring—@CaddyProject mentions boats, but cabins can afford slightly different charge controller placement. Keep your Victron MPPT physically close to whichever string gets shadowed earliest in your specific location. Reduces cable runs and makes troubleshooting simpler when weather inevitably causes partial string issues.

What's your battery capacity looking like for the darker months?

The split array setup you're describing is spot-on for Highland conditions, though I'd push back slightly on one thing—don't underestimate how much those winter angles actually hurt your generation. I've got a similar split configuration on my narrowboat (moored near Loch Lomond), and what really made the difference was tilting the winter array to roughly 55-60 degrees rather than the typical 35-40 you'd run year-round.

What @CarlBaker mentions about hedging is crucial. I'd add that if you're going down this route, consider your cable runs carefully. Running separate strings from different orientations means longer cable runs to your combiner box, and in Scottish damp conditions, you'll want proper IP67 rated connectors throughout. I use Victron MultiPlus inverters paired with their MPPT chargers—the dual-input models give you flexibility if you want to add micro-hydro or a wind source later on.

One practical point: make sure your mounting system accounts for wind loading. Highland exposure is no joke, and undersized brackets are a false economy. How are you planning to handle winter snow accumulation on

Great to see another Highland project getting going! The split array approach is definitely the right call for our latitude – you're getting good coverage across the day without the complexity of tracking systems.

One thing I'd add to what @CarlBaker and @Boycie25 have mentioned: keep a close eye on your shading patterns through winter. Even small obstructions (trees, ridge lines, outbuildings) cast surprisingly long shadows up here. I made the mistake of not accounting for December shade creep on my initial layout – cost me about 15% output until I repositioned one string.

Also, if you haven't already, grab some local irradiance data from PVGIS rather than relying on standard UK figures. The Highlands can vary quite a bit depending on your exact location, and it's worth the extra accuracy for sizing your battery bank properly.

How are you planning to handle the winter storage side of things? That's usually where Highland setups get properly tested. Would be curious to hear your battery capacity targets.

Lefty92

Split arrays are clever and all, but wait until your first Scottish winter when you're cleaning moss off them every fortnight—suddenly that "hedging your bets" approach costs you in ladder time and soggy socks.

@DalesCruiser, what's your tilt angle on those Victron panels? Been running a similar split setup on the narrowboat and found that adjusting seasonally (summer flat, winter steep) actually outperforms fixed mounting up here, though it requires you to not be lazy. Also—and this matters more than anyone admits—those Highland winds will loosen literally everything not welded, so budget for annual bracket checks.

The real question nobody asks: are you running LiFePO₄ or lead-acid? Because if you're getting half-decent winter generation with that 4kW, you'll want batteries that can handle the shallow discharge cycles without pouting.

How's the shade situation looking as the trees grow in?

@EssexNomad's got a point about the maintenance, though I'd say it's less about moss and more about keeping the angles right through the year. That's where the split really pays dividends up there.

Question for @DalesCruiser though — how are you handling the battery charging profile across seasons? I'm running a similar setup down south and noticed the Victron MPPT gets a bit confused in spring/autumn when you're getting those rapid cloud-to-sun transitions. Are you running a Skylla or going straight into your battery bank?

Also curious about your winter strategy. I've got Fogstar LiFePO₄ cells and found they absolutely hate being charged below 0°C, even with a heater. Do you keep your battery box insulated or just accept the efficiency hit during the coldest months?

The Highland latitude gives you mad potential in summer though — jealous of those long charging windows.

The split array approach makes sense for Scottish latitude, though I'd push back slightly on the maintenance narrative here. Yes, you'll need to keep on top of panel cleaning, but it's less about constant graft and more about being methodical—quarterly deep cleans during autumn and spring generally sorts it.

What's worth considering is your inverter sizing relative to that 4kW capacity. If you're running a hybrid Victron setup (MultiPlus or similar), make sure your charge controller can actually deliver what those panels are capable of. I've seen too many Highland builds with oversized arrays but undersized charging architecture. You're essentially leaving capacity on the table.

The real challenge up there isn't the panels themselves—it's the winter generation profile. Even with optimal angles, December and January are brutal for insolation. That's where battery sizing becomes critical. What's your storage capacity looking like? That'll determine whether you need a fossil fuel backup or can genuinely live off solar alone.

Also worth flagging: moss growth is mostly a shading problem, not a cleaning problem. Good roof pitch and ensuring nothing's creating damp microclimates will prevent most of it naturally.

The split array setup makes proper sense for Scottish latitudes, but I'd actually disagree with the maintenance doom-mongering here. Yes, you'll get algae growth on lower-angle panels during damp months, but that's addressable without constant cleaning if you're thoughtful about positioning.

What matters more is which panels you're using. Bifacial panels with anti-soiling coatings perform noticeably better in wet climates — I've got Fogstar units on my narrowboat setup and they genuinely shed debris better than standard monocrystalline. The difference is marked enough that it's worth the upfront cost.

The real consideration for @DalesCruiser is whether they've properly calculated winter irradiance for their cabin's actual latitude and aspect. Highlander geography is brutal — microclimate variations mean a cabin 2km away might see 20% less generation depending on tree-line and valley positioning. I'd strongly recommend actual on-site measurements rather than theoretical calculations before finalising panel angles.

Battery sizing becomes proportionally more critical too. Scottish winter generation dips sharply; undersizing storage is the classic mistake I see.

Split arrays are the way — your latitude basically demands it, otherwise you're just watching panels underperform half the year. Question though: are you East/West facing or have you gone proper dual-axis? The Highlands throw enough cloud at you without gimping your angles.

Also curious about your Victron setup — controller type makes a difference up there with the variable light. MPPT or PWM? I've got a Fogstar hybrid in my van and it absolutely sweats the seasonal changes, but it's doing heavy lifting because I'm not blessed with your cabin square footage for batteries.

That said, maintenance is genuinely grim in Scottish weather — not the moss so much as salt spray if you're coastal, and keeping your connections moisture-sealed when it's damp 300 days a year. Worth checking your array connections monthly in autumn/winter?

Worth noting that split arrays really come into their own when you've got decent roof orientation options. If you're stuck with a single aspect (north-facing loft conversion, say), the performance hit during winter is genuinely brutal — I learned that the hard way with my garden office setup.

The maintenance angle @GoldenNomad mentioned deserves more weight though. Two arrays means twice the cabling, twice the disconnect points, twice the potential for corrosion or loose connections. Up here that matters more than down south. I've had better luck keeping everything accessible rather than optimising tilt angles obsessively.

What's your actual winter generation looking like? The real test with Highland builds is December-January output, not the theoretical annual figures. If you're getting decent power during the dark months, that split is justified. If you're sitting around 200W per kW installed, you might find a single well-positioned array with better battery buffering gives you more reliable power when you actually need it.

What's your battery bank sized at?