Example Data Table
| Appliance |
Watts |
Hours |
Duty |
Estimated Wh |
| LED lights |
24 |
5 |
100% |
120 |
| Roof fan |
36 |
8 |
70% |
201.6 |
| Microwave |
1200 |
0.25 |
100% |
300 |
Formula Used
Appliance watt hours = watts × quantity × hours per day × duty cycle.
AC battery draw = appliance watt hours ÷ inverter efficiency.
DC battery draw = appliance watt hours.
Battery amp hours per day = total battery watt hours ÷ system voltage.
Required battery bank = daily battery watt hours × trip days × safety factor ÷ voltage ÷ usable depth.
Solar watts needed = daily battery watt hours × safety factor ÷ peak sun hours ÷ solar efficiency.
Generator hours = daily battery watt hours × safety factor ÷ charger watts.
How to Use This Calculator
Enter your RV battery voltage, inverter efficiency, battery capacity, usable depth, solar hours, charger watts, trip days, and safety margin.
Add each appliance with watts, quantity, daily use hours, duty cycle, surge multiplier, and load type.
Press the calculate button. Review the result above the form. Download the CSV or PDF file when you need a saved copy.
RV Power Planning for Real Trips
An RV power plan starts with honest appliance use. Every light, pump, fan, charger, fridge, and microwave adds a load. Some devices run all day. Others run for short bursts. This calculator turns those habits into watt hours, kilowatt hours, peak watts, and battery amp hours.
Why Daily Energy Matters
Daily energy is the main planning number. It tells you how much stored power your trip needs each day. A small phone charger may use little energy. A heater fan or air conditioner can change the total quickly. Duty cycle helps model equipment that turns on and off during the day.
Battery and Inverter Sizing
Battery capacity is often shown in amp hours. The calculator converts watt hours into amp hours using your system voltage. It also applies usable depth of discharge. That step is important because many batteries should not be drained fully. Inverter efficiency is included for alternating current loads. This gives a more realistic battery draw.
Solar and Generator Support
Solar recovery depends on peak sun hours and charge efficiency. The calculator estimates the panel watts needed to replace daily use. It also estimates generator runtime when you enter charger watts. These outputs help compare quiet solar charging, shore power, and backup charging.
Using Results Wisely
The result is an estimate, not a guarantee. Real use can change with weather, battery age, wiring losses, and appliance labels. Add a safety margin for cold nights, cloudy days, and long stops. Review the peak running watts before choosing an inverter. Review surge watts before running motors or compressors. A balanced plan protects batteries, avoids overloads, and keeps essential devices available when camping away from hookups.
Better Trip Decisions
Use several scenarios before leaving. Test a light weekend setup. Then test a heavy comfort setup with cooking, entertainment, fans, and extra charging. Compare both results against your battery bank and solar array. This makes limits easy to see. You can reduce hours, change appliances, add panels, or plan generator charging before the trip begins.
Record actual meter readings after each trip. Update appliance hours as habits change. Better records improve future estimates and reveal hidden loads, weak batteries, or devices that deserve replacement soon.
FAQs
What is RV power usage?
RV power usage is the total electrical energy your appliances consume during a chosen period. It is usually measured in watt hours or kilowatt hours.
Why does inverter efficiency matter?
An inverter loses some energy while converting battery power to household power. Lower efficiency means AC appliances draw more battery energy than their label wattage suggests.
What is duty cycle?
Duty cycle is the percentage of time a device actively runs. A fridge compressor may not run constantly, so duty cycle gives a better estimate.
How do I find appliance watts?
Check the appliance label, manual, power adapter, or watt meter. For amps, multiply volts by amps to estimate watts.
Why is battery depth of discharge included?
Batteries should often keep reserve capacity. Usable depth shows how much of the rated battery bank you plan to safely use.
Can this size my solar panels?
It gives an estimate based on daily energy, sun hours, and charging efficiency. Add extra capacity for cloudy weather and seasonal losses.
Does surge wattage affect inverter choice?
Yes. Motors, compressors, pumps, and microwaves can briefly demand more power at startup. Your inverter should handle running and surge loads.
Is this result exact?
No. It is a planning estimate. Real results depend on weather, wiring, battery age, charger settings, and actual appliance behavior.