Example calculation for your setup
Results based on a typical use case
| Appliance | Power | Usage/day | Wh/day |
|---|---|---|---|
| Compression fridge | 45W | 24h | 1080 |
| LED lighting | 20W | 4h | 80 |
| Water pump | 30W | 0.5h | 15 |
| Phone charging | 15W | 2h | 30 |
| Daily consumption | 1205 Wh | ||
Adjust these values with the calculator below
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
| Component | Model | Specs | Price |
|---|---|---|---|
| AGM Battery | Varta LFD90 | 90Ah, 12V, 25kg | ~€120 |
| Solar Panel | Renogy 100W Mono | 100W, 1200x540mm | ~€95 |
| PWM Controller | Renogy Wanderer 10A | 10A, 12V/24V | ~€25 |
| Solar Cables | MC4 + 4mm² | 5m, connectors included | ~€20 |
| Fuse Box | Blue Sea ST Blade | 6 circuits, 12V | ~€35 |
| Fuses + Holders | ANL 60A + blade | Battery + circuit protection | ~€15 |
| Battery Cable | 25mm² red/black | 2m, crimped lugs | ~€20 |
| 12V + USB Outlets | Dual USB + cigarette socket | Flush mount, 2 pieces | ~€25 |
| LED Lighting | 12V spots x5 | 3W each, warm white | ~€30 |
| 12V Wiring | 1.5mm² + 2.5mm² | 10m each gauge | ~€25 |
| Miscellaneous | Lugs, heat shrink, zip ties | Complete wiring kit | ~€40 |
| **TOTAL** | **~€450** |
About this tool
The Challenge: A Complete Van Electrical Setup for Under €500
The electrical system is often the most intimidating part of a van conversion. YouTube builds routinely exceed €3,000. But is all that really necessary to get started?
Our Budget Philosophy
This build is based on 3 principles:
- AGM over lithium — a Varta LFD90 90Ah costs ~€120 vs €400+ for LiFePO4
- PWM over MPPT — a Renogy Wanderer 10A at €25 does the job for a single panel
- One panel only — 100W is enough for 400-500Wh/day in summer in Europe
What This Setup Can Power
- LED lighting: 5 spots x 3W = 15W for 4h = 60Wh
- Smartphone charging x2: 20Wh
- 12V fan: 15W for 6h = 90Wh
- Compact 12V fridge (35L): ~30Ah/day = 360Wh
- Total: ~530Wh/day
With a 90Ah AGM battery (usable capacity ~45Ah at 50% DOD = 540Wh), you just cover one day. The solar panel recharges in 4-5 hours of sun.
Honest Limitations
- No 230V inverter — forget the hair dryer and coffee machine
- No winter autonomy — in December, a single 100W panel produces ~150Wh/day
- Heavy battery — 25kg for a 90Ah AGM vs 10kg for lithium
- Limited lifespan — 300-400 cycles for AGM vs 3,000+ for LiFePO4
Upgrade Path
When you're ready to invest more, the first upgrade is a LiFePO4 100Ah battery (~€350). You'll double your usable capacity and cut the weight by 2.5x.
