How many days can your caravan go without electric hook-up?
Answer four simple questions to find out how many nights you can spend without plugging in.
Step 1 of 4: your trip
When are you travelling?
And what’s the weather forecast?
Why the season matters
In summer, the sun recharges the battery but the fridge works harder. In winter, the heating runs, the evenings are long, the panel produces little and the cold reduces battery capacity.
Travelling in a motorhome or campervan? Calculate a motorhome’s autonomy
In short
A caravan with a 95 Ah AGM battery, a fridge on gas, LED lighting, the water pump, a TV and two phones lasts about 2 days without hook-up in summer, with no solar panel. In winter, the heating fan drains it in less than a day. A 100 Wp panel or a lithium battery extends these durations considerably.
How we calculate
We add up what your appliances use in a day, in watt-hours (Wh), according to the season: heating only counts in spring, autumn and winter, a compressor fridge uses more when it is hot, and lighting more when the evenings are long. Standby loads (control panel, gas detector) are always included. 230 V appliances add the inverter’s losses and its no-load consumption.
A battery is never fully drained. We count half the capacity of a lead-acid battery (AGM or gel), to avoid damaging it, and 80 to 90% of a lithium battery. Cold weather takes 10 to 20% off a lead-acid battery.
Charging comes from the solar panel and, if you drive, from the alternator. For the panel: its power in Wp × the season’s peak sun hours × 55 to 70% efficiency for a panel mounted flat on the roof. Peak sun hours are averages for France, from the north to the Mediterranean, taken from the European Commission’s PVGIS database and adjusted for the weather you choose.
The result is a range: the low end for a power-hungry, cloudy day, the high end for a frugal, bright one. Beyond 14 days, it is no longer the battery that stops you, but fresh water, waste water or gas.
Days without hook-up = usable battery energy ÷ (daily consumption − daily charging)
Appliance consumption, in Wh per day
The values used by the tool, taken from manufacturers’ data sheets (Dometic, Thetford, Truma, Alde, Webasto, Fiamma, ResMed…) for typical use, from the most frugal to the most power-hungry.
| Appliance | Summer | Spring, autumn | Winter |
|---|---|---|---|
| Compressor fridge (Dometic, Thetford…) | 350 – 600 | 230 – 400 | 150 – 280 |
| Absorption fridge, on gas when parked | 5 – 20 | 5 – 20 | 5 – 20 |
| Gas heating (Truma Combi, Alde) | 0 – 20 | 40 – 120 | 120 – 300 |
| Diesel heating (Truma Combi D, Webasto…) | 0 – 20 | 50 – 150 | 150 – 400 |
| LED lighting | 30 – 80 | 50 – 120 | 80 – 160 |
| Water pump | 15 – 40 | 12 – 35 | 10 – 30 |
| Roof vent fan (MaxxFan, Turbo-Vent) | 40 – 200 | 10 – 60 | 0 – 15 |
| 12 V TV and receiver | 50 – 150 | 60 – 170 | 80 – 200 |
| Phone or tabletper device | 10 – 25 | 10 – 25 | 10 – 25 |
| Laptopper laptop | 40 – 120 | 40 – 120 | 40 – 120 |
| E-bike to chargeper bike | 250 – 600 | 250 – 600 | 250 – 600 |
| Kettle, via an inverter | 100 – 250 | 100 – 250 | 100 – 250 |
| Capsule coffee machine, via an inverter | 40 – 120 | 40 – 120 | 40 – 120 |
| Hairdryer, via an inverter | 80 – 200 | 80 – 200 | 80 – 200 |
| CPAP machine (sleep apnoea), without humidifier | 40 – 120 | 40 – 120 | 40 – 120 |
| Standby loads (control panel, gas detector) | 20 – 60 | ||
| Inverter switched on | 30 – 120 | ||
230 V appliances: energy drawn at the socket. The tool adds 8 to 15% for inverter losses.
Three example caravans
Standard caravan, in summer
95 Ah AGM battery, no panel, fridge on gas, heating off, lighting, water pump, TV and two phones, changeable weather.
About 2 days
Between 1.5 days and 2.5 days, depending on the weather and your usage
Compressor fridge and 100 Wp
95 Ah AGM battery, 100 Wp panel, compressor fridge, lighting, water pump, TV and two phones, in summer sunshine.
About 1.5 days
Between 21 hours and 8 days, depending on the weather and your usage
Skiing, in winter
150 Ah lithium battery, 100 Wp panel, gas heating, fridge on gas, lighting, water pump, TV and two phones, changeable weather.
About 3 days
Between 2 days and 5 days, depending on the weather and your usage
6 A, 10 A or 16 A: which campsite hook-up?
A 6 A hook-up (as on many French campsites) gives 1,380 W: enough to charge the battery and run the fridge and lighting, but not an electric heater. A 10 A hook-up (2,300 W) also allows a small fan heater or a kettle, but not both at once. A 16 A hook-up (3,680 W) lets the kettle, hairdryer and heating run without tripping the breaker.
When the campsite provides it, the amperage is shown on its page in the Campernest directory. Bring a 25 m cable and an adaptor for the blue European socket.
Frequently asked questions
How long will a caravan leisure battery last?
A 95 Ah AGM battery, the most common type, gives about 550 Wh of usable energy. With a fridge on gas, lighting, the water pump, a TV and two phones, it lasts about 2 days in summer without a solar panel. With a compressor fridge, expect barely a day.
Does my caravan fridge drain the battery?
An absorption fridge running on gas takes almost nothing from the battery: 5 to 20 Wh a day for its electronics. Left on 12 V when parked, it draws 8 to 15 A and drains the battery in a few hours. A compressor fridge uses 350 to 600 Wh a day in summer: it is often the biggest load.
Can I charge my caravan battery while towing?
Yes, through the 13-pin socket if the caravan and car are wired for it (pin 10, ignition on). The cable is long and thin: expect 35 to 100 Wh per hour of driving, which barely covers one evening. A solar panel is more effective.
What size solar panel do I need for a caravan?
A 100 Wp panel mounted flat produces 275 to 520 Wh a day in summer sunshine, enough for a fridge on gas, lighting and phones. In winter, it only gives 50 to 145 Wh in sunny weather: you will need hook-up if the heating is running.
Should I switch to a lithium leisure battery?
A 100 Ah lithium battery gives 1,000 to 1,150 Wh of usable energy, about twice as much as an AGM of the same capacity, at half the weight. It needs a suitable charger and must not be charged below 0 °C unless it is heated.
Does Truma heating use a lot of electricity?
Gas heating burns gas, but its fan or pump draws 0.5 to 1.5 A. In winter, that comes to 120 to 300 Wh a day: together with lighting, it is a caravan’s biggest load in winter.
10 A or 16 A: which campsite hook-up should I choose?
A 10 A hook-up (2,300 W) is enough to charge the battery and run the fridge and a small fan heater. A 16 A hook-up (3,680 W) also lets you use the kettle and the hairdryer at the same time. Many French campsites still offer 6 A (1,380 W): avoid using an electric heater then.
Sources (1)
- PVGIS, Photovoltaic Geographical Information System (monthly solar radiation) – European Commission, Joint Research Centre
These durations are estimates, not a guarantee: battery age, shade, temperature and your actual usage all make them vary. Keep an eye on your battery level, never take a lead-acid battery below 50%, and never rely on the battery alone for a medical device: keep a hook-up or a back-up solution within reach.