Daily energy use
690Wh
Sum of all selected campsite devices for one day.
RV / Camping Power Calculator
Estimate daily campsite energy use, total trip watt-hours, recommended battery capacity, and optional solar recharge.
Use this for portable fridges, lights, device charging, laptops, and other RV or camping loads. The estimate is based on watt-hours, so actual results can change with weather, appliance cycling, battery condition, and how devices are used.
RV and camping inputs
days
Use the number of days you want the plan to cover.
%
Default 85% accounts for common inverter losses.
%
Battery capacity intentionally left unused for planning margin.
Results
Trip energy use
2,070Wh
3 day trip before efficiency and reserve adjustments.
Recommended battery
2,865Wh
Trip energy adjusted for inverter losses and reserve.
Daily solar recharge
900Wh/day
Estimated daily recharge from the entered solar assumptions.
Solar coverage
130.4%
Daily solar recharge divided by daily energy use.
Device-by-device breakdown
| Item | Value | Notes |
|---|---|---|
| 12V camping fridge (1) | 450 Wh/day | 45 W x 1 x 10 hours per day. |
| LED light bulb (2) | 200 Wh/day | 10 W x 4 x 5 hours per day. |
| Phone charging (3) | 40 Wh/day | 10 W x 2 x 2 hours per day. |
Planning breakdown
| Item | Value | Notes |
|---|---|---|
| Trip length | 3 days | Daily energy is multiplied by this number of days. |
| Trip energy | 2,070 Wh | 690 Wh/day x 3 days. |
| Recommended battery | 2,865 Wh | Trip energy divided by inverter efficiency and usable battery fraction. |
| Solar recharge | 900 Wh/day | Panel watts x peak sun hours x solar efficiency. |
Formula
dailyWh = sum(deviceWatts x quantity x hoursPerDay); totalTripWh = dailyWh x tripDays; requiredBatteryWh = totalTripWh / efficiency / (1 - reserve); dailySolarWh = panelWatts x peakSunHours x solarEfficiencyBattery capacity is sized for the full trip energy after conversion losses and a reserve margin. Solar is shown as an optional daily recharge estimate, not a guarantee that every day will refill the battery.
- dailyWh
- Total watt-hours used by all listed devices in one day.
- totalTripWh
- Daily watt-hours multiplied by the number of trip days.
- efficiency
- Inverter efficiency entered as a decimal, such as 0.85 for 85%.
- reserve
- Battery reserve entered as a decimal, such as 0.15 for 15%.
- dailySolarWh
- Optional daily solar recharge after panel, sun, and efficiency assumptions.
Example
In this example, solar can offset much of the daily use in good sun, but battery reserve still matters for night use and poor weather.
- A 45 W camping fridge runs 10 hours per day for 450 Wh/day.
- Four 10 W lights run 5 hours per day for 200 Wh/day.
- Daily use is 650 Wh, so a 2 day trip uses 1,300 Wh before losses.
- With 85% inverter efficiency and 15% reserve, recommended battery capacity is about 1,799 Wh.
- A 300 W solar array with 4 peak sun hours at 75% efficiency estimates 900 Wh/day of recharge.
How to use this calculator
- Enter the trip length in days.
- Add every device you expect to power at camp.
- Enter each device wattage, quantity, and expected hours per day.
- Adjust inverter efficiency and battery reserve if your equipment or planning margin is different.
- Turn on the solar section if you want to compare daily recharge against daily use.
Input guide
- Trip length: number of days the battery plan should cover.
- Watts: running power draw for each device, based on its label, meter reading, or manual.
- Hours per day: expected daily runtime, including fractions such as 0.5 for 30 minutes.
- Inverter efficiency: estimated conversion loss when using AC output.
- Battery reserve: energy intentionally kept unused for margin.
- Solar inputs: panel watts, equivalent peak sun hours, and charging efficiency for a daily recharge estimate.
Common mistakes
- Using label maximum watts when the real running load is lower.
- Forgetting small always-on loads such as routers or fridge controls.
- Assuming solar panel label watts are delivered all day.
- Planning to use the full rated battery capacity with no reserve.
- Ignoring startup surge or output limits for large compressors, pumps, or air conditioners.
Limitations
This calculator uses simple watt-hour arithmetic. It does not model appliance cycling, changing weather, shading, battery temperature, charge controller behavior, inverter overload limits, campsite rules, or motor starting surge.
FAQ
Should I size for one day or the whole trip?
For battery planning, estimate total trip energy and then account for reserve, efficiency, and any reliable recharging source.
Does solar eliminate the need for battery capacity?
No. Solar output varies daily, so battery reserve is still needed for night use, cloudy weather, and peak loads.
Should I include devices that only run briefly?
Yes. Enter a realistic fraction of an hour per day, such as 0.25 hours for 15 minutes of use.
Can I use this for an RV air conditioner?
Only as a rough energy entry if you know the watts and hours. Large motor loads also need separate surge and system rating checks.
Related calculators
Use these tools to compare campsite battery planning with runtime, solar charging, and generator sizing estimates.
- Portable Power Station Runtime CalculatorEstimate how long a portable power station can run a load after efficiency losses and reserve.
- Solar Panel Charging Time CalculatorEstimate solar charging time from battery size, charge target, panel watts, sun hours, and system efficiency.
- Generator Wattage CalculatorEstimate running watts, starting surge, and a practical generator size for selected backup loads.
Methodology and disclaimer
Camping and RV power estimates depend on actual device wattage, run time, weather, battery age, inverter losses, and charging conditions.
The calculator sums device watt-hours per day, multiplies by trip length, then adjusts the trip energy for inverter efficiency and battery reserve. Optional solar recharge is estimated separately from panel watts, peak sun hours, and solar efficiency.