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I ran 400W of rigid solar on my Sprinter for a full year and tracked every watt. The short answer: 400W is the sweet spot for most van builds — it covers a standard vanlife setup (fridge, lights, laptop, phones) from April through October. November through February, you'll run a deficit.
My test setup: 2× Renogy 200W rigid panels, Victron SmartSolar 30A MPPT, 200Ah LiFePO4 battery. Location: mostly France and Spain. Peak summer (June-July): 1,600-1,900Wh/day. Spring/Fall (Mar-Apr, Sep-Oct): 1,000-1,400Wh/day. Winter (Dec-Jan, northern France): 400-700Wh/day. My daily consumption: ~800Wh/day (fridge, laptop, lights, phones, MaxxFan).
⚡ Expert tip
Clean your panels monthly with a damp cloth. I measured a 7% production drop from dust and bird droppings after 3 months without cleaning. Tree sap is the worst — it partially shades cells and doesn't wash off in rain. Keep a bottle of isopropyl alcohol in the van for tough spots.
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 | ||
Recommended solar panels
302 Wc
4h average sun hours
Adjust these values with the calculator below
VANPOWERCALC PROYOUR ENERGY PROFILE
YOUR ENERGY PROFILE.
This document contains the sizing of your future electrical installation, calculated based on your appliances.
Minimum Daily Consumption
0 WH / DAY
Inventory:
SYSTEM SIZINGPage 2
Battery
To guarantee 0WH without damaging your bank (80% max discharge):
0 AH
LiFePO4 12V
Solar
Minimum power required to recharge your consumption:
0 W
via MPPT
220V AC
Maximum power (with 25% safety margin).
0 W
No Need
Safety & CablingPage 3
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
FUSIBLE
FUSIBLE
BOÎTE À FUSIBLES 12V
Pompe, Leds, Frigo...
CONVERTISSEUR 220V
NON REQUI
PRO GEARPage 4
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
GENERATED BY VANPOWERCALC PRO - UNLIMITED.
About this tool
From April to October, 400W produced more than I consumed every single day — battery stayed at 80-100% perpetually. Pure energy abundance. The trouble starts in November. In northern France/UK/Germany, December production dropped to 400-600Wh — below my 800Wh consumption. I ran a daily deficit of 200-400Wh, draining the battery by about 20% per day. By day 3-4, I needed to either drive (DC-DC charger) or find shore power. In southern Spain that same December, production was 800-1,000Wh — still enough. Geography matters enormously. My recommendation: 400W is perfect for the van sweet spot of 3-season travel in temperate climates. If you winter in Scandinavia or northern UK, add more solar or accept that you'll supplement with driving and shore power. If you're a digital nomad pulling 1,200Wh/day, go 600W.
Frequently asked questions
Is 400W solar enough for a van?▼
For 3-season travel with 800Wh/day consumption: yes. April-October production exceeds demand. In winter at northern latitudes: no, you'll run 30-50% short. In southern Europe/US year-round: mostly yes. 400W is the sweet spot for most builders.
How much does 400W solar produce per day?▼
Summer (5+ PSH): 1,600-1,900Wh. Spring/Fall: 1,000-1,400Wh. Winter northern Europe: 400-700Wh. Southern US/Mediterranean winter: 800-1,200Wh. Real numbers from my Sprinter with Victron MPPT tracking.
Should I get 400W or 600W solar?▼
400W if you're a standard vanlifer (fridge, lights, phones, occasional laptop). 600W if you're a digital nomad (all-day laptop + monitor + router) or plan to winter in northern climates. The third panel costs $80-150 and a 50A MPPT upgrade.
Do 400W panels fit on a van roof?▼
Two 200W panels fit any standard van roof (Transit, Sprinter, Ducato) with room to spare for a MaxxFan and antenna. Dimensions: each panel is roughly 150×70cm. Total roof coverage: about 2.1m² — well within any van roof area.
400W with 100Ah or 200Ah battery?▼
200Ah. With 400W solar and 100Ah, you'll frequently hit 100% charge by noon and waste afternoon solar production (nowhere to store it). 200Ah gives you enough buffer to store a full day's production and survive a cloudy day without stress.