An RV solar calculator helps you size solar panels and a battery bank for your RV, camper, or van based on your actual daily power consumption. Add each appliance you use, specify how many hours per day it runs, and the calculator determines the right solar wattage and battery capacity to keep your system running off-grid.
Add Appliances
Click a preset to add it, or enter a custom appliance below. Adjust watts and hours as needed.
Add Custom Appliance
System Configuration
US average: 4-5 hours
System Recommendation
Panel Size Options
| Panel Size | Panels Needed | Total Watts |
|---|
Consumption Breakdown
| Appliance | Watts | Hours/Day | Wh/Day |
|---|
How to Use the RV Solar Calculator
Sizing a solar and battery system for your RV, camper van, or travel trailer starts with understanding how much power you actually use each day. An undersized system leaves you without power on cloudy days, while an oversized one wastes money and roof space. This RV solar calculator walks you through the process step by step.
Step 1: Add Your Appliances
Click the preset buttons to quickly add common RV appliances like LED lights, a 12V fridge, phone charger, laptop, and fan. Each preset comes with a typical wattage and hours-per-day estimate. You can also add custom appliances by entering the name, wattage, and daily usage hours. The calculator keeps a running total of your daily watt-hour consumption as you build your list.
Step 2: Configure Your System
Choose your battery type: lithium (LiFePO4) batteries allow 80% depth of discharge, while lead-acid (AGM) batteries should only be discharged to 50% to preserve their lifespan. Set your peak sun hours based on where you typically camp. The US average is 4-5 hours, but the Southwest can see 6-7 hours while the Pacific Northwest may get only 3-4. Select days of autonomy (how many days your battery should last without solar charging) and system efficiency.
Step 3: Review the Results
Click Calculate Solar & Battery Size to see your recommended system. The results include your total daily consumption in watt-hours, the battery bank capacity needed in amp-hours at 12V, the total solar panel wattage required, and a breakdown showing how many 100W, 200W, or 400W panels you would need. The recommendation accounts for your chosen depth of discharge, autonomy days, sun hours, and system efficiency losses.
Tips for RV Solar Sizing
Start conservative: it is much easier to add a panel later than to replace an undersized battery bank. For full-time boondocking, plan for at least 2 days of autonomy. Consider that high-draw appliances like coffee makers and microwaves run for very short periods but require a large inverter. If your daily usage exceeds 3,000 Wh, consider a 24V or 48V system instead of 12V to reduce wire gauge requirements and improve efficiency. Always round up your battery bank to the nearest available size, as batteries come in standard capacities like 100Ah, 200Ah, and 300Ah.
Frequently Asked Questions
Is this RV solar calculator really free?
Yes, completely free with no signup required. All calculations run locally in your browser. Use it as many times as you need to compare different configurations for your RV or van build.
Is my data safe when using this calculator?
Absolutely. Everything runs entirely in your browser using JavaScript. No appliance data, power usage, or personal information is transmitted anywhere. You can even use it offline once the page loads.
What is the difference between lithium and lead-acid batteries for RVs?
Lithium (LiFePO4) batteries can safely discharge to 80% depth of discharge (DOD), while lead-acid batteries should only discharge to 50% DOD to preserve battery life. Lithium batteries are lighter, last longer, and charge faster, but cost more upfront.
How many peak sun hours does my location get?
Peak sun hours vary by location and season. The US Southwest averages 5-7 hours, Southeast 4-5, Midwest 3.5-4.5, and Northwest 3-4. For van life and travel, using 4 hours is a conservative default that works for most US locations.
What does system efficiency mean for RV solar?
System efficiency accounts for real-world losses from the charge controller, wiring resistance, battery charging losses, temperature effects, and panel angle. A typical RV solar system operates at 75-85% efficiency, meaning you lose 15-25% of rated panel output.
How many solar panels do I need on my RV?
It depends on your daily power consumption and sun exposure. A typical RV using lights, a fridge, phone charging, and a laptop needs about 1,000-1,500 Wh per day, which requires 300-500W of solar panels. This calculator sizes the system based on your specific appliance list.
Should I add days of autonomy to my battery bank?
Days of autonomy means your battery can last through cloudy days without solar charging. For boondocking, 2 days of autonomy is recommended. For campground use with shore power available, 1 day is usually sufficient.
Can I run a microwave or air conditioner on RV solar?
High-wattage appliances like microwaves (1,000W) and AC units (1,500W+) require large battery banks and inverters. They are possible with a substantial solar setup but dramatically increase system size and cost. Many RV owners use propane alternatives for cooking and cooling instead.