RV Solar & Battery Bank Sizing Calculator
Planning an off-grid electrical upgrade requires balancing your 24-hour amp-hour consumption against solar replenishment rates and battery reserve capacity. Use our interactive calculator below to model your daily electrical loads and get verified hardware recommendations.
RV Solar & Battery Bank Calculator
Estimate required solar wattage, LiFePO4 battery capacity, and MPPT charge controller sizing for off-grid boondocking.
Recommended System Specifications
Recommended Hardware & Direct Sizing Matches
Drop-in upgrade for lead-acid. 10-year lifespan, 1/3 the weight, flat voltage curve.
View Rated Batteries on Amazon →High-efficiency bypass diode panels with mounting Z-brackets and MC4 cables.
View Solar Panel Kits on Amazon →How to Calculate Your RV Electrical Loads
Your RV electrical system operates on two distinct circuits: 12V DC (battery power running lights, water pump, furnace fan, and 12V refrigeration) and 120V AC (shore power or inverter power running microwave, coffee maker, TV, and air conditioning).
1. Sizing Your Battery Bank (LiFePO4 vs. Lead-Acid)
Traditional flooded lead-acid or AGM batteries can only be discharged to 50% depth of discharge (DOD) without accelerating plate degradation. In contrast, modern Lithium Iron Phosphate (LiFePO4) batteries safely deliver 90% to 100% of their rated capacity while maintaining steady voltage above 12.8V. A 200Ah LiFePO4 bank delivers 200 usable amp-hours (~2,560 watt-hours), equivalent to a 400Ah lead-acid bank at one-third the physical weight.
2. Sizing Solar Panels for Reliable Replenishment
To replace 80 Ah of daily consumption (1,024 Wh), accounting for a standard 20% system loss through wiring, angle variance, and charge controller efficiency, you need approximately 1,280 Wh of solar harvest. In a region receiving 4.5 peak sun hours per day, this requires a minimum of 285 Watts of solar panels. We round up to 400 Watts (two 200W monocrystalline panels) to guarantee full battery absorption during partly cloudy conditions.
3. MPPT vs. PWM Charge Controllers
Always choose Maximum Power Point Tracking (MPPT) over Pulse Width Modulation (PWM) for RV installations. MPPT controllers step down high solar panel voltage to battery charging voltage while boosting charging current, extracting 15% to 30% more energy in colder morning temperatures.