How to Size a Solar System for Your RV: A No-Math Guide

The number one question from new boondockers: how much solar do I need? Most answers involve spreadsheets. This one doesn't.

Start With Your Battery Bank, Not Your Panels

Solar panels refill your batteries. So the first question is: how much battery storage do you need? A simple rule of thumb: add up the amp-hours you use in a day and double it. That doubling gives you a 50% discharge buffer, which is important for battery longevity.

Typical Daily Usage

• Lights (LED) — 5–10Ah/day
• Phone/laptop charging — 10–20Ah/day
• 12V fridge — 40–60Ah/day (the big one)
• Fan or vent — 5–15Ah/day
• Water pump — 2–5Ah/day

A typical setup without air conditioning runs 80–120Ah per day. Double that = 160–240Ah of battery storage.

Now Size Your Panels

A rough rule: 100W of solar produces about 30–40Ah per day in good sun (5 peak sun hours). So for 200Ah of daily use, you want 400–600W of panels.

The Starter Kit That Works

For most weekend to week-long boondockers: 200W of solar + 100Ah lithium battery. This handles lights, phone charging, and a 12V fridge comfortably in summer. Add a second 100Ah battery if you're in cloudy climates or running a CPAP.

Lithium batteries are worth the price. They charge faster, discharge deeper (80% vs 50% for AGM), and last 5–10× longer.