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The promise of a caravan is freedom — and nothing limits that freedom faster than running out of power two nights into a free camp. Get the electrical system right and you can sit beside a river for a week with the fridge humming and your devices charged. Here’s how off-grid power actually works, without the jargon.

The four parts of an off-grid system

Think of it as a small, self-contained power station:

1. Solar panels — your income. They turn daylight into charge while you’re parked.
2. Battery — your savings. It stores energy for the fridge overnight, cloudy days and after dark.
3. Chargers (DC-DC + solar MPPT) — the plumbing. They charge the battery efficiently from your solar panels and from the car’s alternator while you drive.
4. Inverter — the translator. It converts stored 12V battery power into 240V mains power for household appliances.

A good monitor ties it together so you can see, at a glance, how much power you have left.

Lithium vs AGM: the battery decision

This is the choice that defines the whole system.

• AGM (lead-based): cheaper up front, but heavy, and you can only safely use about half its rated capacity before you risk damaging it. A “100Ah” AGM realistically gives you ~50Ah.
• Lithium (LiFePO₄): more expensive up front, but far lighter, you can use most of its capacity, it charges faster, and it lasts many more cycles. A 100Ah lithium gives you close to 100Ah of usable power.

For genuine off-grid touring, lithium usually wins on usable power per kilo — which matters twice over, because weight is precious on a caravan (see our towing-weights guide).

How to size a system

You don’t need to be an electrician — just add up what you use in a day.

1. List your 12V loads and roughly how long each runs: fridge, lights, water pump, phone/laptop charging, fans.
2. Estimate daily use in amp-hours (Ah). A typical compressor fridge might use 30–60Ah a day; lights and pumps add a bit more. Many couples land somewhere around 60–120Ah per day.
3. Match storage to that. You want enough usable battery for at least one full day with nothing coming in — so a day’s use of ~100Ah suggests ~100Ah of usable lithium as a floor, more if you want a buffer for cloudy days.
4. Match solar to replace it. As a rough guide, plan for solar that can put back roughly what you take out on an average day — which is why 400–600W of panels is common on off-grid vans.

These are starting points, not gospel — real numbers depend on your fridge, the season and where you camp. But the method is sound: know your daily draw, then build storage and solar around it.

What the inverter does (and doesn’t)

The inverter lets you run 240V appliances — a laptop charger, a TV, kitchen gadgets. What it’s not built for is high-draw heating appliances (kettles, toasters, hair dryers, air-con) for long periods; those flatten a battery fast. Plan to run those on mains power when you’re hooked up, and keep the inverter for the small stuff off-grid.

Why component quality matters out here

Off-grid gear lives a hard life — heat, corrugations, deep discharge cycles, remote locations where a failure ends the trip. This is the one area where premium, proven components earn their keep. It’s why our upgrade options use systems like Victron for power management: when you’re 300km from the nearest town, reliability isn’t a luxury.

A few field tips

• Park to keep panels out of shade — even a small shadow disproportionately cuts output.
• A portable panel you can angle toward the sun beats a flat roof panel on short winter days.
• Lithium dislikes charging in freezing temperatures; quality systems manage this for you.
• Watch your monitor for the first few trips — you’ll quickly learn your real daily rhythm.