RV Electrical Load Calculator
Free 12V power calculator for RV, camper and van. Calculate daily amp-hour usage, battery runtime and solar panel sizing. Plan your boondocking power budget.
Quick add common devices:
Understanding 12V Power
Amp-Hours (Ah) Explained
Amp-hours measure battery capacity and consumption. If a device draws 5 amps for 2 hours, it uses 10 amp-hours (5A x 2h = 10Ah).
Battery Depth of Discharge
Lead-Acid/AGM: Should only be discharged to 50% to preserve lifespan. A "100Ah" battery really only gives you 50Ah of usable power.
Lithium (LiFePO4): Can safely discharge to 80-90%. More expensive upfront but more usable capacity and longer lifespan.
Solar Panel Sizing
The "Solar Needed" estimate assumes 4-5 sun-hours per day (average US conditions). In winter or cloudy areas, add 25-50% more panels.
Tips for Reducing Power Use
- Switch all lights to LED - uses 1/10th the power of incandescent
- Use propane for heating/cooking instead of electric
- 12V compressor fridges use 1/3 the power of absorption fridges
- Turn off inverter when not in use - standby draw adds up
Can You Run A/C on Battery?
Technically yes, but it's impractical for most setups. A roof A/C draws ~13A at 120V, which translates to ~125A at 12V through an inverter. One hour of A/C uses 125Ah - more than most battery banks hold! You'd need a massive lithium bank (400Ah+), a 2000W+ inverter, and serious solar. Most RVers run A/C only on shore power or generator.