RV/Van Life Generator Sizing Calculator
Created by: Daniel Hayes
Last updated:
Find the right generator size for your RV or van camping needs. Calculate running and starting wattage requirements, account for elevation derating, and estimate fuel consumption for informed purchasing decisions.
What is an RV/Van Life Generator Sizing Calculator?
A Generator Sizing Calculator helps RV and van owners determine the right generator size for their camping needs. Calculate running and starting wattage requirements, account for elevation derating, and find the optimal balance between power and portability.
Whether you need to run air conditioning, charge batteries, or power multiple appliances, this calculator considers all your electrical loads and camping conditions to recommend the ideal generator capacity.
Understanding Generator Sizing
Running Watts: Continuous power needed to operate your appliances
Starting Watts: Extra surge power needed when motors start up
Elevation Derating: Power loss at high altitudes due to thinner air
Simultaneous Load: Percentage of devices running at the same time
Frequently Asked Questions
What size generator do I need for my RV?
Generator size depends on what you want to run. A 2,000-watt inverter generator handles basics (lights, fans, chargers, TV). For a 13,500 BTU AC unit, you need at least 3,000 watts. Running AC plus other appliances requires 3,500-4,000+ watts. Calculate your total running watts and add 20% for starting surges.
What's the difference between running watts and starting watts?
Running watts (rated watts) is the continuous power an appliance needs during operation. Starting watts (surge watts) is the extra power needed when motors start, typically 2-3x running watts for a few seconds. Your generator must handle starting watts to prevent tripping breakers. AC units and refrigerators have high starting demands.
Should I get an inverter generator or conventional generator?
Inverter generators are best for RV use: they produce clean power safe for electronics, run quieter, are more fuel-efficient, and are lightweight. Conventional generators are cheaper and more powerful but louder and produce dirtier power. Most RVers prefer inverter generators despite higher cost.
How much fuel does an RV generator use?
Fuel consumption depends on generator size and load. A 2,000W inverter at 50% load uses about 0.3-0.5 gallons per hour. A 3,500W at full load uses 0.5-0.8 gal/hr. Larger built-in RV generators (4,000W+) use 0.5-1.0+ gal/hr. Running at eco mode or lighter loads significantly improves efficiency.
Can I run my RV air conditioner on a 2,000-watt generator?
Possibly, but it's marginal. A 13,500 BTU AC needs about 1,500 running watts but 2,800-3,500 starting watts. Some 2,000W generators with high surge ratings can start smaller ACs, especially with soft-start kits. For reliable AC operation, a 3,000-3,500W generator is recommended.
What is a soft start kit and do I need one?
A soft start kit reduces AC compressor starting surge by 65-75%, from 3,000W+ down to under 1,000W. This allows smaller generators to run AC units reliably. They cost $100-300 and are easy to install. Essential if you want to run AC on a 2,000W generator or run two ACs on a smaller generator.
How does altitude affect generator performance?
Generators lose about 3.5% power for every 1,000 feet above sea level due to thinner air. At 5,000 feet, expect 17.5% less power; at 8,000 feet, 28% less. If you camp at high elevations frequently, size your generator larger to compensate. Some generators have altitude adjustment kits.
How do I reduce generator noise while camping?
Reduce generator noise by: using an inverter generator (quietest type), placing it away from your RV and neighbors, using a generator box or baffle, pointing exhaust away from campsites, running at eco mode when possible, and using a longer extension cord to increase distance. Many campgrounds have quiet hours - respect them.
Sources and References
- Honda Generators - Sizing Guides
- Champion Power Equipment - Generator Selection
- Cummins Onan - RV Generator Solutions
- Westinghouse - Portable Generator Guide