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Off-grid with your camper van: become self-sufficient
Going off-grid — free camping without shore power, water hookups or other facilities — is the ultimate goal for many camper van converters. But how much power, water and preparation do you need to truly be self-sufficient? Power, water and heat are not separate problems: each one decides how long the others last.
Plan your off-grid setup
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The three pillars of off-grid: power, water and heating
Self-sufficient camping revolves around three systems:
Power: you need a combination of generation (solar panels), storage (batteries) and smart consumption. Without shore power, everything must come from your own system.
Water: a sufficiently large fresh water tank and the discipline to use water sparingly. Plus a way to refill.
Heating: on cold nights you need an independent heat source. Diesel heating is the most popular for off-grid.
How well you size these three systems determines how many days you can truly stay off-grid.
Power: how many solar panels and battery?
For off-grid you need more capacity than for campsite use. Plan for:
Solar panels: 300-400Wp for average use in Southern Europe. 400-600Wp for Northern Europe or shoulder seasons. In winter in Northern Europe, solar panels alone are insufficient.
Battery capacity: minimum 200Ah lithium (or 400Ah AGM (absorbent glass mat, a sealed lead battery)). This gives you 1-2 days buffer in cloudy weather.
Backup: a B2B (battery to battery, a charger between the starter and house battery) charger (charging while driving) is essential. If you drive little, consider a small generator as emergency backup.
Saving power: the best way to go off-grid is to use less. LED lighting, an efficient compressor fridge and charging your laptop via 12V makes a huge difference.
Water: how long can you last?
Water is often the limiting factor for off-grid stays.
How long you last depends entirely on what you count. Worked out with the water calculator for two people:
- Drinking, cooking, washing up and brushing teeth only: 24 litres a day, so 3.4 days on an 80 litre tank and 5 days on 120 litres
- Add hand washing and a flushing toilet: 50 litres a day, and that same 80 litre tank is empty after a day and a half
- Add a daily shower inside: 90 litres a day, and you will not make it through 24 hours
So the jump is not in the tank size but in the showering. Shower outside or skip it and you double your autonomy without carrying a litre more.
Tips to save water:
- Use a foot pump or low-flow faucet
- Wash dishes in a basin, not under running water
- Shower briefly or use a solar shower
- Collect rainwater for dishes (not for drinking)
Refilling water: look for public taps, cemeteries, sports parks or camper service points. Apps like park4night show fill points.
Heating and cold nights
Without shore power you need an independent heat source:
Diesel heater (e.g. Webasto, Eberspächer, or cheaper Chinese alternatives): by far the most popular. Uses 0.1-0.3 liters of diesel per hour and draws 1-3A from your battery. You can heat for hours on a few liters of diesel from your driving tank.
Gas heating: works well but gas bottles are heavy and running out in remote locations is inconvenient.
Wood stove: romantic but impractical as sole source. Requires lots of storage space for wood and a chimney pipe.
Passive: good insulation is the foundation. A well-insulated camper van loses much less heat, meaning you need less heating. Invest in insulation first before buying a bigger heater.
Work out your energy balance before buying panels
Living off-grid is less about having many solar panels and more about knowing how much goes in per day and how much comes out.
A common daily demand in a self-built camper looks like this:
- Compressor fridge: 18 W averaged over 12 hours of running, 216 Wh in total
- LED lighting: 25 Wh
- Roof fan: 25 W for 6 hours, 150 Wh in total
- Water pump: 30 Wh
- Tank sensor that stays on day and night: 24 Wh
Together that is about 450 Wh a day. Work inside on a laptop and roughly 230 Wh comes on top, because the inverter costs you some 15 percent on the way. Run the diesel heater for eight hours as well and you are over 850 Wh a day.
Put your yield next to that. A 400 Wp (watt peak, the output under test conditions) system delivers around 1,600 Wh a day in summer, 960 Wh in spring, 480 Wh in winter and 320 Wh on a grey day. That factor of five between June and December is why a set-up that is generous in summer runs flat after two days in November.
The battery is your buffer, not your source
Solar panels decide how much comes in per day, the battery decides how many bad days you can bridge. Those are two different problems, and they call for two different sizes.
You cannot use everything printed on the label. With lithium you count on 80 percent, with lead-acid on 50 percent, otherwise the battery wears out quickly. A 200 Ah battery at 12 V holds 2,400 Wh; of that, 1,920 Wh is usable if it is lithium and 1,200 Wh if it is lead.
At 450 Wh a day that means four days with no top-up at all on lithium, and two and a half days on lead. Use 850 Wh and it drops to two days and a day and a half respectively.
That is also why lithium often works out cheaper despite the purchase price: you need half the capacity for the same autonomy, and that saves weight and space too.
In winter your power comes from the engine
A charger between the starter battery and the leisure battery, often called a DC-DC or B2B charger, is your main charging source through the dark half of the year. Many builders treat it as an extra and change their mind in November.
A 30 A DC-DC charger at 12 V delivers around 360 W. With its efficiency of roughly 90 percent, an hour of driving puts some 320 Wh into the battery. Two hours of driving therefore yields more than a whole winter day with 400 Wp on the roof.
That makes the winter sum a different one from the summer sum. Park in one spot for a week in December and solar will not carry you. Drive a couple of hours every other day and the problem largely disappears.
Watch the size of your alternator: a 50 A charger draws well over 60 A on the other side at 12 V, and alongside everything else the vehicle runs, that is often too much for a standard alternator.
Where you may park differs by country
Technology is only half of off-grid. The other half is where you put the van that night, and those rules vary widely.
In the Netherlands wild camping outside a campsite is banned almost everywhere, with a handful of designated spots as the exception. In Germany you may stop for one night in many places to rest, but not camp: no awning, no chairs outside. Scandinavia has right-to-roam rules with more freedom. In France, Spain and Portugal it differs per municipality, and enforcement along the coast is generally stricter.
What helps everywhere:
- Arrive late and leave early
- Put nothing outside and leave no waste behind
- Use a toilet you empty yourself rather than a bush
- Do not park five campers together in the same spot
The practical reason to take this seriously is that spots close as soon as they get messy. Every place you leave tidy is one you can use again next year.
Plan your off-grid setup
Use our free tools to calculate your power consumption, solar panels and battery capacity for off-grid living.
Frequently asked questions
- How many days can I stay off-grid in my camper van?
This depends on your power and water supply. With 200Ah lithium, 300Wp solar panels and an 80L water tank, you can easily stay 5-7 days off-grid in summer in Southern Europe. In winter, power is the limiting factor.
- Are solar panels alone enough for off-grid?
In summer in Southern Europe, often yes. In shoulder seasons or Northern Europe, you need supplementation via a B2B charger (charging while driving) or shore power when available. A pure solar setup is not sufficient in winter in Northern Europe.
- What is the difference between off-grid and wild camping?
Off-grid means you don't use external facilities (power, water). Wild camping means staying outside a campsite. You can be off-grid at a campsite (without hooking up) or wild camp with shore power (at some stellplatz). Note: wild camping is not allowed everywhere.
- How many solar panels do I need for 500 Wh a day?
In summer 500 Wh comes out of roughly 125 Wp, because a system yields about 4 Wh per Wp per day at five sun hours. In spring you need over 200 Wp for it and in winter over 400 Wp. So anyone wanting to stand out all year does not size for June. In practice 400 Wp on the roof is comfortably enough from March to October and too little in December.
- Can I stay off-grid in winter on solar alone?
Not in north-west Europe. A 400 Wp system yields around 480 Wh a day in December and 320 Wh on a grey day, while a camper with a fridge, lighting, ventilation and heating easily wants 850 Wh. You then need a charger from the alternator, or you head south. Two hours of driving with a 30 A charger yields more than that whole winter day of sun.
- How big should my water tank be?
That depends above all on whether you shower inside. Worked out with the water calculator for two people: with drinking, cooking, washing up and brushing teeth only you land on 24 litres a day, which is 3.4 days on an 80 litre tank and 5 days on 120 litres. Count hand washing and a flushing toilet as well and it becomes 50 litres a day, leaving that 80 litre tank empty after a day and a half. With a daily shower inside it climbs to 90 litres a day. Put your own habits into the water calculator; the tank size is rarely the problem, the showering is.
- How much power does a compressor fridge use?
Count on about 216 Wh over 24 hours for a common 12 V compressor fridge: it draws around 45 W while the compressor runs, and at normal outside temperatures that is roughly half the time. In heat it climbs, because it cycles more often. It is usually the largest fixed item in a camper's energy balance.