Caravan Solar Kit Sizing: How Many Watts Do I Actually Need?

Choosing the right size solar kit for your caravan can be confusing. Pick too small, and your batteries will constantly run low. Go too big, and you may overspend on panels you don’t really need. This guide will help you work out how many watts of solar power you actually need for your caravan setup.

Step 1: Work Out Your Daily Power Usage

Start by listing the appliances you plan to run in your caravan. Each appliance uses a certain number of watts (W) and will be run for a certain number of hours per day.

Example:

? In this example, the caravan needs around 720Wh per day (0.72kWh).

Step 2: Convert Watt-Hours Into Battery Capacity

Your solar panels don’t power devices directly — they charge your batteries. Most caravan setups use 12V batteries, so we convert watt-hours into amp-hours (Ah).

Formula:
Watt-hours ÷ Battery Voltage = Amp-hours

For 720Wh per day:
720 ÷ 12V = 60Ah per day

So the system needs to recharge around 60Ah of battery power daily.

Step 3: Match Solar Panel Output to Your Needs

Now, consider how much energy your panels can realistically produce. A 100W solar panel in good sun provides about 25–30Ah per day (after real-world losses).

Using this estimate:

• 200W Solar Kit → ~50–60Ah/day

• 300W Solar Kit → ~75–90Ah/day

• 400W Solar Kit → ~100–120Ah/day

? From our example, the caravan needs around 60Ah/day, so a 200W solar kit would just cover it. To allow for cloudy days, extra devices, and battery inefficiency, going up to 300W or 400W is a safer choice for reliability.

Step 4: Factor in Travel Style & Location

• Short weekend trips → Smaller kits (100–200W) may be fine.

• Full-time touring or off-grid camping → Larger kits (300–600W) recommended.

• Tropical/Coastal areas → Expect some shading from trees; oversize your system.

• Outback/desert → Strong sun, but dust reduces output; regular cleaning is a must.

Step 5: Don’t Forget Battery Size

Solar panels must work with a battery bank big enough to store your energy. As a rule of thumb:

• 200W Kit → 100Ah battery minimum

• 400W Kit → 200Ah battery minimum

• 600W Kit → 300Ah battery minimum

Lithium batteries (LiFePO₄) are more efficient than AGM, meaning you can use almost all their stored capacity.

Quick Caravan Solar Sizing Guide

• Weekend Camping (lights, phone, small fridge) → 200W Kit + 100Ah Battery

• Extended Touring (fridge, lights, TV, laptops, fans) → 300–400W Kit + 200Ah Battery

• Full Off-Grid Living (large fridge, appliances, multiple devices) → 500–600W Kit + 300Ah Battery

Final Thoughts

The right solar kit size depends on your daily power use, travel style, and battery capacity. As a rule, it’s better to oversize your solar panels slightly so you have power on cloudy days and room for future upgrades.

If you’re unsure, check out our Complete Caravan Solar Kits or get in touch — we’ll help you choose the perfect setup for your adventures.

Caravan Solar Kit Sizing Guide diagram