Static caravan solar — worth going bigger than you think from the start?

Made the classic mistake last year of starting small and "seeing how it goes." Fitted a single 200W panel on the roof of our static, wired it to a modest 100Ah lead-acid battery through a basic PWM controller. Felt proud of myself for about a fortnight until a run of grey November days left me with a flat battery and a very cold kettle situation.

Ended up ripping it all out over winter and starting again properly. Now running 600W of panels (three Renogy 200W monos), a Victron SmartSolar MPPT 100/30, and a 200Ah Fogstar Drift lithium. Night and day difference — even in January I'm keeping lights, the router, and a small 12V fridge ticking over without drama.

The thing nobody told me was how much the static's roof angle and orientation matters more than it would on a pitched house roof. Mine faces roughly south-southwest and sits at a pretty shallow pitch, so I lose a fair bit in winter compared to what the calculators promise. Anyone else found the same? And did you end up adding a small ground-mount array to compensate, or just accept the seasonal hit?

@MoreTeaVicar oh, the classic "I'll just dip my toe in" approach 😄 — been there with my narrowboat before I eventually caved and went properly off-grid.

The painful truth is that the wiring and mounting infrastructure is often the expensive bit, not the panels themselves. If you'd run slightly beefier cable runs and fitted a larger charge controller from the start, adding panels later is relatively painless. Retrofitting undersized cable is a nightmare.

Worth noting: 100Ah lead-acid is really only ~50Ah usable — that catches so many people out. Same physical space, a Fogstar Drift LiFePO4 gives you genuinely usable capacity.

What PWM or MPPT controller did you go with originally? That's often the bottleneck people overlook before the battery even becomes the issue.

@MoreTeaVicar mate, my garden office taught me the same lesson — the only thing worse than not enough solar is having to crawl back onto the roof six months later to bolt on more panels because your first "experiment" worked too well.

Go big, go Victron, go Fogstar lithium — future you will be absolutely delighted, present you will briefly wince at the invoice.

@MoreTeaVicar classic false economy situation. A static caravan roof has finite usable space — work out your maximum viable panel capacity now and size the cable runs, fusing, and charge controller for that full figure from day one, even if you're only populating half the panels initially.

Victron SmartSolar MPPT controllers are worth the premium precisely because you can right-size one for your eventual array rather than replacing a cheap PWM unit eighteen months later. Same logic applies to battery cabling — 35mm² DC runs aren't cheap to retrofit once walls are lined.

On storage: 100Ah lead-acid on a static is genuinely inadequate for anything beyond lighting. Fogstar or CATL-based LiFePO4 at 200Ah minimum gives you usable capacity without the depth-of-discharge anxiety. Lead sulphation from shallow cycling is a silent killer.

@MoreTeaVicar the boat taught me this lesson painfully. Spent two seasons chasing adequate power before finally ripping everything out and starting properly with a Victron MPPT and a decent Fogstar lithium bank.

The turning point was realising I wasn't buying a system — I was buying headroom. Every appliance you'll ever want to add, every cloudy January week, every unexpected guest staying longer than planned — headroom absorbs all of it silently.

With the garden office I deliberately overspecced from day one. Zero regrets.

The maths that finally clicked for me: the cable runs, the mounting, the time on the roof — that's where your real cost sits. The extra panels themselves are almost trivial by comparison. Doing it twice costs far more than doing it right once.

Size for what you want, not what you currently need.

@MoreTeaVicar completely relate to this! I went through exactly the same process with our static up in the Dales. What nobody tells you upfront is that the wiring is often the biggest hidden cost when you upgrade later — I had to redo nearly everything when I scaled up, because the cable runs I'd originally laid weren't rated for the higher current. If I'd just planned for a larger system from day one, the cable costs would've been identical. Factor in a proper MPPT controller with headroom, oversized cable runs, and a battery bank you can actually expand without rewiring, and future-you will be enormously grateful. The panels themselves are almost the cheap bit these days.