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
| Inverter | Wave type | Power | Standby | App | Price |
|---|---|---|---|---|---|
| Victron Phoenix 12/500 | Pure sine | 500W | 11W | ✓ | $100-130 |
| Victron Phoenix 12/1200 | Pure sine | 1,200W | 11W | ✓ | $200-260 |
| Victron Phoenix 12/2000 | Pure sine | 2,000W | 11W | ✓ | $300-380 |
| Generic 1000W | Modified | 1,000W | 20-40W | ✗ | $40-80 |
About this tool
How to Size an Inverter for Your Van or Campervan
An inverter converts your 12V battery power to 230V AC for standard appliances. Getting the size right is critical — too small and you trip it under load; too large and you waste money on an oversized unit that's inefficient at light loads.
The Inverter Sizing Formula
Required inverter wattage = Peak simultaneous 230V load × 1.25
The 1.25 safety factor accounts for:
- Startup surges (motors can spike 2-3× running watts when starting)
- Inverter derating in high ambient temperatures
- Future additions to your setup
Appliance Load Reference
| Appliance | Running Watts | Startup Surge | Notes |
|---|---|---|---|
| Laptop charger 65W | 65W | 65W | No surge |
| MacBook Pro 96W charger | 100W | 100W | No surge |
| External monitor | 20-50W | 20-50W | No surge |
| CPAP machine | 30-60W | 60-120W | Small motor surge |
| Hair dryer (travel) | 800-1,200W | 1,200W | High! |
| Kettle 1L | 1,500-2,000W | 2,200W | High! |
| Coffee maker | 800-1,000W | 1,000W | Check your model |
Quick Inverter Selection Guide
| Your Primary 230V Use | Min Inverter Size | Recommended |
|---|---|---|
| Laptop + phone + accessories only | 600W | 1,000W |
| Laptop + monitor + CPAP | 800W | 1,500W |
| Above + occasional kettle | 2,000W | 2,500W |
| All of the above + coffee maker | 2,500W | 3,000W |
Critical: Battery Cable Sizing for Your Inverter
| Inverter Size | 12V Peak Current | Min Cable Size | Max Cable Length |
|---|---|---|---|
| 1,000W | ~100A | 25mm² (4 AWG) | 500mm |
| 2,000W | ~190A | 50mm² (1/0 AWG) | 400mm |
| 3,000W | ~280A | 70mm² (2/0 AWG) | 300mm |
Mount your inverter within 500mm of your battery. Longer battery cables at these currents cause dangerous voltage drop.
Pure Sine Wave Efficiency at Different Loads
Pure sine wave inverters are less efficient at very low loads (5-10% capacity). A 2,000W inverter running a 100W laptop charger sits at 5% load – efficiency drops to 80-85%. If you mostly run small loads, a 1,000W inverter is more efficient than a 2,000W inverter for the same daily use.
Expert tip: If you only want to charge laptops and run a coffee maker occasionally, a 1,500W pure sine inverter is the sweet spot — efficient at light loads, capable of handling realistic high peaks. The Victron Phoenix 12/1600W is the community favorite at this size.