Off-grid, RV & cabin
Pick your rig size and how you travel. Get an instant ballpark solar and battery size, no load math required.
How it works An off-grid system lives or dies on upkeep. The roof penetration maintenance cost tool in our Maintenance & Lifespan section can help you plan cleaning and inspection costs over the years.
Step 1
A rough size category is enough for a ballpark, no exact measurements needed.
Step 2
Weekend trips, extended boondocking, and full-time living have very different typical power needs.
Step 3
No load calculation required. Use this as a starting point, then run the full calculator for a buying-ready number.
For light weekend use, around 300 watts of solar and 150Ah of battery is a common starting point for a mid-size travel trailer. For regular extended boondocking, that typically rises to about 500 watts and 300Ah, reflecting the larger daily load of longer stays away from shore power and hookups. Once you have that number, the federal ITC calculator shows what it means for the rest of the system.
Full-time living means running a fridge, electronics, and other daily-use appliances every single day without a return trip home to recharge or restock, so the system has to sustain itself indefinitely rather than bridge a short weekend gap. This typically pushes recommended system size two to three times larger than an occasional weekend setup, which is why the usage tier matters as much as rig size in this quick estimate. Current figures live on the DOE's solar photovoltaic technology basics, which updates them when the program changes.
This estimator leans on typical rig usage for the size and travel style you pick, but it can't account for unusual appliances or particularly heavy specific loads, like a large inverter microwave, an electric space heater, or a power-hungry entertainment setup. Someone with an unusually appliance-heavy rig should treat this estimate as a floor, not a ceiling, and lean toward the full wattage calculator for anything beyond a rough starting conversation.
This quick tool is meant for an initial ballpark, budgeting conversation, or a fast sanity check, built on the same production data as NREL's PVWatts solar calculator. Before actually buying panels or batteries, run the RV solar wattage calculator and RV daily load calculator with your specific appliances for a number that accounts for your actual setup rather than a general category.
Rounding up to the next common panel or battery size, rather than buying the exact ballpark figure, gives useful cushion as usage tends to grow over time. Most RV owners add devices and appliances after their initial setup, so a little extra capacity from the start avoids an early upgrade. The quick 5-minute system size estimator in our system sizing tools is a useful second opinion once you have a ballpark figure, and the federal ITC calculator in our rebates and incentives tools is worth checking before finalizing a budget, alongside DOE's solar photovoltaic technology basics for the fundamentals.
Questions
A quick estimate gives a reasonable ballpark based on typical usage patterns for your rig size, but it can't account for unusual appliances or heavy specific loads like a large inverter microwave or an electric space heater. Use the full RV solar wattage calculator for a number you'll actually buy equipment against.
For light weekend use, around 300 watts of solar and 150Ah of battery is a common starting point. For regular extended boondocking, that typically rises to about 500 watts and 300Ah, reflecting the larger daily load of longer stays away from shore power.
Full-time living means running a fridge, electronics, and other daily-use appliances every single day without a return trip home to recharge everything, so the system has to sustain itself indefinitely rather than just bridge a short weekend. This typically pushes system size two to three times larger than an occasional-use setup.
A little headroom is generally a good idea, since actual usage tends to grow over time as people add devices and appliances. Rounding up to the next common panel or battery size, rather than buying the exact ballpark number, gives some built-in cushion.