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
| Wire Size | AWG Equiv | Max Current | Max Fuse | Typical Use |
|---|---|---|---|---|
| 2.5mm² | 14 AWG | 25A | 20A | Fridge, lights, heater |
| 4mm² | 12 AWG | 32A | 30A | Fridge, 12V devices |
| 6mm² | 10 AWG | 50A | 40A | MPPT 30A, USB hub |
| 10mm² | 8 AWG | 65A | 60A | MPPT 50A, small loads |
| 16mm² | 6 AWG | 80A | 80A | 500W inverter |
| 25mm² | 4 AWG | 120A | 100A | 1000W inverter |
| 50mm² | 1/0 AWG | 170A | 150A | 2000W inverter |
| 70mm² | 2/0 AWG | 210A | 200A | 3000W inverter |
About this tool
Correct wire sizing is non-negotiable in a van electrical system. Here is the complete guide with real examples for every major load.
Core formula: wire must carry the load current at max 2% voltage drop for power circuits (fridge, inverter) and 3% for lighting. Voltage drop: ΔV = (2 × L × I × ρ) ÷ A — where L = one-way wire length in metres, I = current in amps, ρ = resistivity of copper (0.0175 Ω·mm²/m), A = cross-section in mm².
Common van loads — correct wire sizing:
- 12V compressor fridge (45W, 3.75A): minimum 2.5mm² (14 AWG), max run 5m → use 4mm² (12 AWG) for safety margin
- 12V diesel heater (max 10A start pulse): minimum 2.5mm² (14 AWG), use 4mm² with 15A fuse
- 100W LED strip lighting (8A): minimum 2.5mm² (14 AWG) with 10A fuse
- Victron MPPT 100/30 solar controller (30A output): minimum 6mm² (10 AWG) with 40A fuse
- 1000W inverter at 12V (100A input): minimum 25mm² (4 AWG) with 150A fuse within 30cm of battery
- 2000W inverter at 12V (200A input): minimum 70mm² (2/0 AWG) with 250A fuse, run max 1m from battery
- 3000W inverter at 12V (280A input): two runs of 70mm² in parallel with 300A Class T fuse
Fusing rules: every positive wire running from the battery must be fused within 30cm of the battery (before any junction or load). Fuse rating = wire rating × 0.80 (not the load current). A 6mm² wire is rated for 50A continuous → use 40A fuse.
Battery cables: the highest-current run in any van build is from battery bank to bus bars or inverter. For LiFePO4 batteries in parallel: each battery needs its own correctly sized cable of equal length (within 5cm) to the bus bar — unequal lengths cause unequal current sharing and accelerated aging.
Tinned vs bare copper: in high-humidity environments (van condensation, coastal use), tinned copper wire oxidizes much slower. Popular choice: marine-grade tinned OFC (oxygen-free copper) 105°C rated for all runs in the van.