Tools in This Collection
RV Solar Calculator
Size solar panels based on daily power consumption and sun hours
RV Battery Bank Calculator
Calculate battery capacity needed for overnight power autonomy
RV Inverter Sizing Calculator
Find minimum inverter wattage for your AC appliance loads
Van Electrical Calculator
Size complete van conversion electrical systems
RV Fuel Cost Calculator
Estimate trip fuel cost by distance and MPG
RV Trip Budget Calculator
Calculate total trip cost including fuel, campsites, and food
RV Towing Calculator
Check towing capacity, tongue weight, and GVWR simultaneously
Vehicle Payload Calculator
Calculate available payload before exceeding GVWR
RV Water Tank Calculator
Estimate how many days your fresh water tank lasts
RV Depreciation Calculator
Project RV value decline over time to optimize buy/sell timing
RV Electrical and Trip Planning Workflow
Building or outfitting an RV or van involves two distinct phases: sizing the electrical system before you build, and planning trip costs before you roll. Getting electrical sizing right before purchase is far cheaper than retrofitting. Getting towing and weight calculations right is a safety issue.
Solar Sizing: Start with the Load Analysis
Off-grid electrical systems start with a daily load calculation. A typical van conversion with a 12V fridge (40Ah/day), LED lighting (5Ah/day), laptop charging (20Ah/day), and phone charging (5Ah/day) uses about 70Ah daily. The RV Solar Calculator takes your full appliance list and your camping region's average sun hours (3.5 hours/day in the Pacific Northwest, 6 hours in the Southwest desert) to calculate required solar panel wattage. For 70Ah daily at 12V in a 4-sun-hour region: 70Ah x 12V / 4h x 1.25 (inefficiency) = 262W minimum — round up to 300-400W for weather margin.
Battery Bank Sizing
The RV Battery Bank Calculator determines how much battery capacity you need to run overnight (12 hours without solar) without depleting below the safe threshold. Lithium (LiFePO4) batteries can safely discharge to 20% capacity; lead-acid to 50%. For 70Ah daily on lithium: size for 2 days of autonomy = 140Ah usable, which means 175Ah rated capacity (at 80% depth of discharge). A 200Ah LiFePO4 bank provides comfortable margin.
Inverter Sizing
The RV Inverter Sizing Calculator finds the minimum inverter wattage for your AC loads. Add the wattage of all appliances you might run simultaneously: microwave (1,000W), laptop charger (65W), and phone charger (18W) = 1,083W peak. Size to 1,500W minimum with a 2,000W unit recommended for headroom on surge loads (microwaves often draw 20-30% above rated wattage on startup).
Towing Safety
The RV Towing Calculator checks all three towing limits simultaneously: max towing capacity, tongue weight rating (typically 10-15% of trailer weight), and tow vehicle GVWR. A 5,000-lb trailer requires a vehicle rated for at least 5,000 lbs towing, with a tongue weight rating of at least 500 lbs. Exceeding any one limit is unsafe even if the others have margin — the calculator shows all three checks at once.
Trip Budget and Fuel Cost
Fuel is typically 30-50% of total RV trip variable costs. At $3.50/gal in a rig getting 8 MPG driving 300 miles, fuel alone costs $131.25. The RV Fuel Cost Calculator estimates total fuel by trip distance and MPG. The RV Trip Budget Calculator adds campsite fees ($25-75/night), food, and activity costs for a full trip picture. Full-hookup sites average $50-75/night; dispersed (free) boondocking is the budget traveler's alternative.
Water Planning for Boondocking
The RV Water Tank Calculator estimates how many days your fresh water tank covers based on daily usage. At 3 gallons/person/day for cooking, drinking, and basic hygiene, a 40-gallon tank covers 2 people for about 6-7 days — realistic for extended boondocking without hookups.
Frequently Asked Questions
How many solar panels do I need for a van or RV?
Start by totaling your daily power consumption in amp-hours (Ah). A typical van with fridge, lighting, and device charging uses 60-80Ah/day. Divide by your region's average sun hours (3.5 in the Pacific Northwest, 6 in the desert Southwest) and multiply by 1.25 for inefficiency losses: 70Ah x 12V / 4h x 1.25 = 262W minimum. Round up to 300-400W for cloudy-day margin. The RV Solar Calculator does this automatically from your appliance list.
How do I calculate RV towing capacity safely?
Three limits apply simultaneously: (1) Max towing capacity — your vehicle's rated trailer weight limit. (2) Tongue weight rating — typically 10-15% of trailer GVWR; exceeding it affects steering and braking. (3) Tow vehicle GVWR — your vehicle's total weight including driver, passengers, cargo, hitch, and tongue weight. Run all three checks with the RV Towing Calculator before purchasing a trailer.
What does a typical RV trip cost per day?
Fuel is typically $50-150/day depending on distance and rig MPG (Class A motorhomes average 6-10 MPG; fifth wheels towed by trucks average 8-12 MPG). Campsites average $25-75/night for partial or full hookups; free dispersed camping eliminates this cost. Food varies by cooking-in vs. eating out. Total variable costs for a couple range from $100-250/day for moderate travel with campsite stays.
Should I use lithium or lead-acid batteries in my RV?
Lithium (LiFePO4) batteries safely discharge to 20% capacity (80% usable) versus 50% for lead-acid, giving double the usable capacity at the same rated size. They also last 2,000-3,000 cycles versus 300-500 for lead-acid, charge faster, and weigh roughly half as much. The higher upfront cost is typically recovered in 3-5 years through longer lifespan. The RV Battery Bank Calculator shows both options so you can compare.