How Big a Solar Setup Do You Need for Camping? A Simple Sizing Method
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The most common camping solar mistake is buying a panel first and hoping it's enough. It's much easier to work backward from what you actually plan to power. Here's a four-step method, with a worked example.
Step 1: List your devices and their daily energy
Energy is measured in watt-hours (Wh): a device's power in watts multiplied by the hours you use it. For battery-powered gadgets, use the battery's capacity in Wh, which is usually printed on it or in the specs, times how many charges you need per day.
| Device | Daily use | Wh per day |
|---|---|---|
| Phone (about 15 Wh battery) | 2 charges | 30 |
| Headlamp | 1 charge | 5 |
| Camera (about 10 Wh battery) | 2 batteries | 20 |
| 10 W USB fan | 5 hours | 50 |
| Laptop | 1 charge | 60 |
| Total | 165 | |
Step 2: Add a safety margin
Charging and power conversion waste energy, and you'll always use a bit more than planned. Add 25%: 165 × 1.25 ≈ 206 Wh per day.
Step 3: Size the panel
What matters is peak sun hours: the equivalent number of hours of full, direct sunlight per day. In most of the US in summer, about 4 is a reasonable planning figure; it's lower in winter, in forests and at high latitudes. Real-world panels also deliver only about 75% of their rated wattage once heat, angle and dust are counted.
Panel watts = daily Wh ÷ peak sun hours ÷ 0.75 = 206 ÷ 4 ÷ 0.75 ≈ 69 W. Round up to a 100 W panel, which leaves room for a cloudy day.
Step 4: Size the battery
Your battery should carry you through a day or two with little sun. For two days of autonomy: 206 × 2 = 412 Wh. Lithium iron phosphate (LiFePO4) batteries can use about 90% of their capacity, so 412 ÷ 0.9 ≈ 458 Wh. A 500 Wh portable power station fits. With lead-acid batteries, which you should only drain to about 50%, you'd need roughly twice the rated capacity.
The result
For this example kit: a 100 W panel plus a 500 Wh LiFePO4 battery. Swap in your own devices and the same four steps work for a weekend tent trip or a full-time van build.
Go further
The Adventure-Ready Solar Kit Planner turns this method into fill-in worksheets and calculators, from device audit to shopping list. For charge controllers, inverters, wiring and complete tent, van and RV setups, see The Solar Camping Blueprint.
For permanent installations, follow local electrical codes and consult a licensed electrician.