Most RVers buy solar panels based on roof space or budget. This is backward. You must size your system based on your consumption.
Step 1: Calculate Your Daily Watt-Hours
Make a list of everything you plug in. Be honest. If you run a CPAP machine or charge a laptop for 8 hours, write it down.
- Lights (LED): 5 watts x 4 hours = 20 Wh
- Laptop: 60 watts x 8 hours = 480 Wh
- Starlink: 50 watts x 10 hours = 500 Wh
- Furnace Fan: 80 watts x 4 hours = 320 Wh
- Total Daily Need: ~1,320 Wh
Step 2: Size the Battery Bank
You need enough storage to get through the night and cloudy days. We recommend 2x your daily consumption for safety.
1,320 Wh x 2 = 2,640 Wh of storage.
In 12V terms, that is roughly 200Ah of Lithium (LiFePO4).
Recommended Batteries
Step 3: Size the Solar Array
You need to replenish that 1,320 Wh daily. On average, you get about 4-5 peak sun hours per day.
1,320 Wh / 5 hours = 264 Watts.
Because panels are rarely 100% efficient (dust, heat, angle), add a 20% buffer. You need roughly 320W to 400W of solar to be self-sufficient.