YOUR ENERGY PROFILE.
This document contains the sizing of your future electrical installation, calculated based on your appliances.
Inventory:
Battery
To guarantee 0WH without damaging your bank (80% max discharge):
Solar
Minimum power required to recharge your consumption:
220V AC
Maximum power (with 25% safety margin).
12V Cable Sizing Guide
Use this professional reference table to select the correct gauge (mm²) for your cables. For 12V in a van, the maximum tolerated voltage drop is 3%. Always use multi-stranded flexible automotive wire.
| Current (A) | Round trip < 2m | Round trip 4m | Round trip 6m |
|---|---|---|---|
| 5A (LEDs, USB) | 1.5 mm² | 2.5 mm² | 4 mm² |
| 10A (Fridge, Pump) | 2.5 mm² | 4 mm² | 6 mm² |
| 20A (Heater) | 4 mm² | 10 mm² | 10 mm² |
| 50A (DC/DC Booster) | 10 mm² | 16 mm² | 25 mm² |
| 100A (Inverter) | 25 mm² | 35 mm² | 50 mm² |
Fuse Sizing
The fuse protects the wire, not the appliance. Always place it as close to the power source as possible (battery or busbar).
- Wire 1.5 mm² → Max fuse 10A
- Wire 2.5 mm² → Max fuse 20A
- Wire 4 mm² → Max fuse 30A
- Wire 6 mm² → Max fuse 40A
- Wire 10 mm² → Max fuse 60A
SCHÉMA ÉLECTRIQUE
PANNEAUX SOLAIRES
0W
REGULATEUR MPPT
BATTERIE AUXILIAIRE
0 Ah
Lithium LiFePO4
BOÎTE À FUSIBLES 12V
Pompe, Leds, Frigo...
CONVERTISSEUR 220V
NON REQUI
SHOPPING LIST
Where to find this equipment? Here is the community-approved selection.
12V 6-way Fuse Box
Mandatory protection
Digital Multimeter
Test your connections
Heavy Duty Crimping Tool
For perfect lugs
Heat Shrink Tubing
Insulation and safety
Comparison table
| Panel watts | Wh/day (SW USA) | Wh/day (NE USA) | Wh/day (UK) |
|---|---|---|---|
| 100W | 650-750 | 500-600 | 400-500 |
| 200W | 1,300-1,500 | 1,000-1,200 | 800-1,000 |
| 300W | 1,950-2,250 | 1,500-1,800 | 1,200-1,500 |
| 400W | 2,600-3,000 | 2,000-2,400 | 1,600-2,000 |
About this tool
RV solar panel sizing follows the same core principles as van solar, but with critical differences: larger roof area, the option for slide-out mounting, different load profiles (AC units, larger appliances), and mixed use between shore power and off-grid. Understanding these differences helps right-size an RV solar system without over-engineering.
RV load profiles differ significantly from van builds: RVers typically have AC climate control (either rooftop or heat pump, 1500-3500W), microwave (1200-1500W), TV entertainment (100-300W), space heating (electric or propane), and residential-sized fridges (600-1200Wh/day on a 120V compressor). Total daily consumption for a full-timing RV can reach 5000-8000Wh/day — requiring 1500-2500W of solar plus 800-1200Ah of lithium storage for full off-grid independence.
Practical RV solar sizing constraints: a standard Class C motorhome has approximately 10-15m² of usable roof area — theoretically supporting 2000-3000W of panels at 200W/m². In practice, air conditioner shrouds, roof vents, slide toppers, and ladder obstruct 30-50% of area. Real sustainable installs: 600-1500W for Class B+ (larger vans like Roadtrek), 1000-2500W for Class C, 2000-5000W for Class A motorhomes.
Batteries for RV solar: LiFePO4 is the only chemistry that makes sense for serious RV solar. The faster charge acceptance (1C vs 0.2C for AGM) allows high-amperage solar to fill the bank in 3-4 hours vs 8+ hours. For 5000Wh/day consumption: 600Ah LiFePO4 minimum (providing 2 days: 2× 5000Wh ÷ 12V = 833Ah; with some cloud recovery from generators/shore power: 600Ah is often sufficient with 1500W+ solar).
Generators as solar complement in RVs: most serious full-timing RVers run a propane or gasoline generator (Honda EU2200i, Generac iQ3500) 1-2 hours/day when solar is insufficient. This hybrid approach is more cost-effective than doubling the solar array for the 20% of days when weather is poor. A 2000W generator charging at 120A (80% of 150A charger rating) adds 80Ah of LiFePO4 charge per hour — effectively serving as a powerful "solar backup" day.
Class B RV specifics (converted vans): the same sizing rules as campervans apply, but Class B builders often have higher budgets and add: roof-mounted 12V air conditioners (Dometic RTX 2000: 400W), larger batteries (400-600Ah LiFePO4), lithium-compatible alternator upgrades (Li-BIM + smart alternator controller), and 1000W+ shore power inverter/chargers for campground connectivity.