Your fridge runs overnight, the lights stay on after sunset, and the roof has limited space between vents. Choosing a caravan solar setup starts with those constraints: how much energy the appliances use, how much sunlight reaches the panels, and how long the battery must carry the load without charging.
What does a caravan solar setup include?
A caravan solar setup is a system of solar panels, a charge controller, a leisure battery and protected wiring that supplies the caravan's electrical loads. The governing sizing equation is panel power = daily energy consumption / (peak sun hours × delivery factor).
The calculations here use an assumed 4 peak sun hours per day as the sunlight input. Replace that assumption with a location-specific input for your travel season before using the results to select hardware.
The delivery factor represents the difference between nameplate energy and energy available at the chosen measurement boundary. This article assumes 0.75 at the battery bus for its calculations; that is an illustrative planning input, not a measured result or a universal recommendation.
A caravan solar panel kit needs electrical compatibility across the complete charging path. Panel operating voltage must suit the controller, and the controller's charging settings must suit the locally sourced battery.
How much solar do you need to run a caravan?
A caravan using an assumed 1,200 Wh per day needs 400 W of solar at 4 peak sun hours and a 0.75 delivery factor. The required wattage changes directly with daily consumption and inversely with available sunlight.
Calculate each load as watts × operating hours. For a cycling fridge, use measured daily energy or compressor running hours rather than assuming its rated power applies continuously.
| Load | Assumed power | Daily operating time | Daily energy |
|---|---|---|---|
| Fridge compressor | 40 W | 15 hours | 600 Wh |
| Lighting | 20 W | 6 hours | 120 Wh |
| Water pump | 60 W | 1 hour | 60 Wh |
| Electronics | 50 W | 2 hours | 100 Wh |
| Fan | 40 W | 8 hours | 320 Wh |
| Total | Sum of listed loads | Listed daily schedule | 1,200 Wh |
For the same load and delivery factor, 2 peak sun hours require 800 W; 3 require approximately 533 W; and 5 require 320 W. Use sunlight conditions for the travel season and parking location rather than an annual average that hides the difficult months.
Roof shading changes the available input. A roof plan showing vents and clear mounting areas belongs beside the energy calculation; the guide to flexible panels on vehicle roofs covers the corresponding panel-fit decisions.
What battery setup suits a caravan?
The best battery setup for a caravan is one with enough usable watt-hours for the required autonomy and a charging system compatible with its chemistry. For an assumed 1,200 Wh daily load and 2 days without charging, the battery must deliver 2,400 Wh.
Calculate nominal capacity as daily Wh × autonomy days / allowed usable fraction. Assuming a 12.8 V battery and an allowed usable fraction of 0.80, capacity = 1,200 × 2 / (12.8 × 0.80) = 234.4 Ah.
An illustrative 12.8 V, 250 Ah battery therefore stores 3,200 Wh nominally and provides 2,560 Wh under that assumption. Its calculated autonomy is 2,560 / 1,200 = approximately 2.13 days, excluding additional loads and battery discharge losses.
Confirm the usable fraction, temperature limits and charge settings against the selected battery documentation. Battery chemistry alone does not establish suitability: the battery management system, charger and maximum discharge current must match the appliances.
Source the battery locally and coordinate its specification with the panel and controller package. Keep the leisure supply separate from the starting battery through the vehicle's appropriate charging arrangement.
Can solar panels power the whole caravan?
Solar panels can power a caravan when delivered daily solar energy covers daily consumption and battery storage covers periods without sunlight. A system sized for lighting and refrigeration does not automatically cover electric cooking or air conditioning.
An assumed 1,000 W appliance running for 6 minutes uses 100 Wh at its output. With an assumed inverter efficiency of 0.90, the battery must supply 100 / 0.90 = 111 Wh, before any inverter standby consumption.
Instantaneous power needs a separate check. That same appliance draws approximately 1,000 / (12.8 × 0.90) = 86.8 A at the assumed battery voltage, so the battery, inverter and wiring must support the current even though the operating period is short.
A solar power kit for caravan use therefore needs both an energy budget and a power budget. Record appliance starting requirements separately, and have mains-voltage installation work completed by a qualified installer under the applicable local requirements.
How do you size a caravan system step by step?
A worked caravan sizing calculation begins with 1,200 Wh daily consumption and produces a 400 W energy-balance array under assumed 4-hour sunlight and 0.75 delivery conditions. A 600 W array adds calculated charging surplus under those same conditions.
- Establish daily demand. Multiply each assumed appliance wattage by its daily operating hours and add the results: 600 + 120 + 60 + 100 + 320 = 1,200 Wh.
- Calculate balance wattage. Divide demand by sunlight and delivery factor: 1,200 / (4 × 0.75) = 400 W.
- Calculate storage. For 2 days of autonomy, divide 2,400 Wh by the assumed 12.8 V and 0.80 usable fraction: 234.4 Ah nominal capacity.
- Allow charging surplus. Evaluate an assumed 600 W array: 600 × 4 × 0.75 = 1,800 Wh per day, leaving 600 Wh after the daily load.
- Check controller current. At an assumed 14.4 V charging voltage, 600 / 14.4 = 41.7 A is an idealized power-to-current check; select the controller using its documented ratings and the array's electrical limits.
- Confirm physical fit. Check roof dimensions, mounting attachment and cable routes before treating the calculated panel wattage as an installable package.
The controller check does not replace checking maximum solar input voltage and current. Cold-condition open-circuit voltage, series connections and parallel strings must stay within the controller's documented limits.
How long will solar take to recover after cloudy days?
Caravan battery recovery time equals the accumulated energy deficit divided by daily solar surplus while normal appliances remain running. Under the assumed 1,200 Wh load, a 600 W array delivering 1,800 Wh daily takes 4 days to replace a 2,400 Wh deficit.
The calculation is 2,400 / (1,800 − 1,200) = 4 days. A 400 W array delivering exactly 1,200 Wh daily has no calculated surplus, so it cannot replace that deficit while the same daily consumption continues.
Recovery also depends on the next day's sunlight. At an assumed 2 peak sun hours, the 600 W array supplies 900 Wh and leaves a 300 Wh daily shortfall rather than charging surplus.
Before comparing caravan solar panel kits, choose an acceptable recovery period. Reducing consumption, adding deployable panel capacity or using an alternative charging source changes that period; a larger battery alone does not create additional charging energy.
Which panels and mounts fit the calculation?
Caravan solar hardware should match the calculated wattage, controller limits and available mounting space. Compare a solar panel kit for caravan use by its complete electrical specification rather than its headline panel rating.
For panels, record operating voltage and current, open-circuit voltage, dimensions and connector arrangement. For fixed installations, caravan solar panel mounts need attachment details suited to the roof construction and the loads imposed during travel.
The panel fastener selection guide explains clamp and bolt choices that belong in the mounting specification. Confirm the roof attachment method with the caravan builder or installer before drilling or bonding brackets.
Adjustable solar panel tilt mounts are a hardware option where access and clearance permit adjustment; confirm whether the chosen assembly is suitable for vehicle installation and how it is secured for travel. Portable panels need secure placement and a cable route protected against foot traffic.
For an awkward roof footprint, specify the usable dimensions before choosing standard or custom panels. LinkSolar supplies panel and mounting hardware made by partner production lines, with specification support and pre-shipment checks.
FAQ
How much solar do you need to run a caravan?
A caravan consuming an assumed 1,200 Wh daily needs 400 W at 4 peak sun hours and a 0.75 delivery factor. That wattage balances daily energy; additional capacity provides surplus for recovering battery charge.
What is the best battery setup for a caravan?
A caravan battery setup should provide usable energy equal to daily consumption multiplied by the required autonomy days. For an assumed 1,200 Wh daily load and 2 days of autonomy, that means 2,400 Wh usable storage with compatible charging and discharge ratings.
Can you power a caravan with solar panels?
A caravan can run on solar when generation and storage meet its energy and power requirements. High-power appliances require checking inverter capacity and battery current separately from daily watt-hours.
How do you test a caravan solar panel?
Testing a caravan solar panel requires checking its electrical output against its documented ratings under recorded sunlight and temperature conditions. Inspect connections, then use suitably rated equipment to measure open-circuit voltage and operating output through the controller. Voltage alone does not demonstrate delivered power, and a short-circuit current test requires a correctly rated meter and competent handling.
What does the 33% rule mean for caravan solar?
A 33% rule label alone does not provide enough information to size a caravan solar system. Ask the person specifying that rule to provide its source and equation, including what the percentage measures.
As a separate hypothetical calculation, choosing daily generation equal to 3 times an assumed 1,200 Wh load gives a target of 3,600 Wh and requires 3,600 / (4 × 0.75) = 1,200 W under assumed 4 peak sun hours and a 0.75 delivery factor. That arithmetic illustrates a chosen generation margin; it does not establish the meaning of the 33% rule.
Next step
To get started with a panel specification that fits your caravan's energy calculation and roof space, compare the options on the custom solar panel specification page.