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
| Option | Liters/use | Electric draw | Cost approx. |
|---|---|---|---|
| Outdoor shower (drum) | 5-10L | Pump 30W → 0.2Ah | $0/shower |
| 12V electric heater | 10L | 180W × 30min = 90Wh | $80-150 |
| Gas heater | 10L | Pump only ~2Wh | $60-120 + gas |
| Solar camp shower | 6-10L | Pump only ~2Wh | $20-40 |
| Diesel boiler | 10L | ~30Wh pump | $400-800 |
About this tool
Hot Water in a Van: Comparing Electrical and Non-Electrical Options
Having hot water in a van is a game-changer for comfort — but the power implications vary wildly between systems. This guide covers the real electrical cost of each option so you can make the right choice for your build.
Hot Water Options Compared
| System | Power Required | Hot Water Time | Best For |
|---|---|---|---|
| Propane tankless (Camplux 5L) | 0W (gas only) | Instant | Off-grid freedom |
| 12V DC immersion heater | 100-150W | 20-40 min (10L) | Simple solar builds |
| Diesel heater with hot water | 10-30W (fan) | 30-45 min | Cold climates |
| Electric tankless (230V) | 2,000-3,500W | Instant | Shore power only |
| Solar thermal collector | 0W | 2-4h of sun | Summer use only |
| Heat exchanger (engine coolant) | 0W | While driving | Supplemental only |
12V Immersion Heaters: The Solar-Friendly Option
A 12V immersion heater rated at 100-150W can heat 10L of water in 20-40 minutes — enough for a daily shower. For 30 minutes of heating: 120W × 0,5h = 60Wh = 5Ah. That's very manageable with 200W of solar.
Recommended setup: a 10-15L insulated tank with a 12V immersion element, gravity-fed from a roof tank. The water stays hot for hours if the tank is well-insulated (neoprene sleeve). Cost: 30-60€ for the immersion element, 40-80€ for the tank.
Propane Tankless Heaters: Zero Electrical Cost
The Camplux 5L and similar propane tankless heaters are the king of off-grid hot water. Electrical consumption: near zero (just a piezo igniter). The trade-off is propane gas cost (one 3kg bottle lasts 4-8 weeks for a single person) and the regulatory complexity of propane in some countries.
A 5L/min unit at 6 kW heats cold water (15°C) to shower temperature (38°C) at 2,3L/min — comfortable for a shower. For a couple, upgrade to 8L/min.
Diesel Heater Integration: The Winter Choice
Webasto and Espar diesel heaters can be fitted with a hot water heat exchanger circuit. The electrical consumption stays at just 10-30W (for the fan) while the diesel burner heats the water. This is the most power-efficient option for winter van life in cold climates.
A Webasto Thermo 90 can heat a 10L tank from 15°C to 60°C in 30-35 minutes while also heating your cabin — two birds with one stone.
230V Electric Tankless: Shore Power Only
At 2,000-3,500W, a 230V electric tankless heater requires a large inverter (minimum 3,500W pure sine) and drains even 400Ah LiFePO4 batteries in under 90 minutes. Use this only if you spend most nights at campsites with shore power.
Expert tip: The best hot water setup for full-time van life is a combination: propane tankless for daily showers, plus a small 12V immersion heater for quick hand-washing or dishes. Total power cost: under 20Wh/day for the 12V element, zero for the propane unit. Total cost: under €150.