RV solar calculator
Size an RV solar starting point
Translate estimated daily amp-hours into solar array, battery-bank and charge-controller targets. Real output changes with season, latitude, shade, panel angle and weather.
Enter 12.8V-equivalent amp-hours. If measured at another voltage, multiply amp-hours by that voltage, then divide by 12.8; or divide daily watt-hours by 12.8.
Use a conservative seasonal figure for where and when you camp.
More autonomy increases battery capacity; it does not guarantee solar recovery.
Use the actual manufacturer limits for the battery you choose.
This helps frame inverter size; add headroom for motor or compressor surge.
Calculations use 12.8V or 25.6V for LiFePO4, and 12V or 24V for lead-acid. Battery amp-hours and controller current are reported for the selected system.
Your planning range
—solar array target
—battery-bank target
—minimum controller current
Assumes 25% harvest/system-loss headroom and the selected usable-battery percentage. Verify panel open-circuit voltage, controller limits, conductor ampacity, fusing, disconnects, inverter surge and manufacturer instructions.
Solar output is not the same every day.
Design for the difficult season
Summer desert output does not represent shaded forest camps or low winter sun.
Plan more than one charging source
Shore power and properly designed alternator charging can make an RV system far more resilient.
Protect every conductor
High-current DC systems require correct wire sizes, fuses, disconnects, terminations and secure mounting.