RV Solar Calculator
Enter your appliances and usage hours — get a complete RV solar system spec.
How to Use This Calculator
Enter your appliance loads
The appliance checklist covers the eight most common RV power consumers. For each one, enter the wattage (check the appliance label or manual) and hours per day you use it. The 12V fridge column uses average draw — a compressor fridge that's rated 60W will cycle on and off, so 24 hours is correct as an average load.
Pick a scenario first
Not sure about your usage? Start with a scenario. Weekend warrior covers light weekend use. Snowbird adds afternoon AC. Full-timer sizes for a work-from-the-road lifestyle with heavy laptop use. Minimalist covers a no-AC, basics-only setup. Adjust the pre-filled values to match your actual appliances.
Set roof space and boondocking days
Available roof space limits how many panels you can mount — enter the actual flat, unobstructed area. Boondocking days between charges is how many nights you need to run off battery without solar input (cloudy days, heavily shaded campsites). This drives battery bank sizing more than anything else.
Interpret the results
The calculator outputs four numbers: panel watts, battery Ah at 12V, charge controller amps (MPPT), and inverter size. If your roof can't fit enough panels, an orange warning tells you how many panels actually fit — a signal to use higher-wattage panels (300-400W) or add a generator for high-draw appliances like microwave and AC.
The Formula
The 50% depth of discharge (DoD) limit protects lead-acid batteries. If you use lithium (LiFePO4), you can safely draw to 80-90% — meaning your actual battery pack can be smaller than this calculator shows. The 80% system efficiency accounts for MPPT losses, wiring, and temperature derating.
Example
Sarah & Mike — Full-time RV travelers, Southwest
Sarah works remotely, Mike cooks. They run a 12V compressor fridge 24/7, a laptop 6 hours, and occasionally the rooftop AC in the afternoon. They camp in the Southwest desert (5.5 peak sun hours) and want 3 days of battery backup.
Result
Four 200W panels fit their 120 sq ft roof. For batteries, 770 Ah at 12V means four 200Ah lead-acid batteries wired in parallel — or two 200Ah lithium batteries (which can discharge to 80%, cutting the bank nearly in half). The 73A MPPT controller handles the 700W array perfectly.