The single biggest factor in electrical system sizing is how you use the van. A weekend build and a full-time rig have fundamentally different requirements.
Weekend use: how it actually works
A weekend user drives out Friday evening and returns Sunday or Monday. They have:
- A full battery leaving home
- 2–3 nights of power use
- A drive home to recharge via the alternator
- Potentially limited or no solar in shaded camping spots
What this means technically:
- Battery only needs to cover 2–3 days without full recharge
- Solar is helpful but not critical — the drive recharges the battery
- No need to be self-sustaining indefinitely
Weekend system: 100Ah LiFePO4 + 200W solar + 20A DC-DC
| Component | Weekend spec |
|---|---|
| Battery | 100Ah LiFePO4 |
| Solar | 200W |
| MPPT controller | 20A |
| DC-DC charger | 20A (Renogy DCC20S) |
| Inverter | 1,000W (if needed) |
Cost of components: ~$700–$1,000. This handles a fridge, phone, LED lighting, and laptop for 2–3 nights comfortably.
Full-time use: what changes
A full-timer may park for 3–5 days in the same spot, work from their laptop all day, cook meals, and not drive every day. They need:
- 2–3 days of battery autonomy without any charging
- Enough solar to be self-sustaining in moderate conditions
- DC-DC charging for driving days
Full-time system: 200–300Ah LiFePO4 + 300–400W solar + 30A DC-DC
| Component | Full-time spec |
|---|---|
| Battery | 200–300Ah LiFePO4 |
| Solar | 300–400W |
| MPPT controller | 30–40A |
| DC-DC charger | 30A (Renogy DCC30S or Victron Orion XS 30A) |
| Inverter | 2,000W |
| Battery monitor | Victron SmartShunt + BMV-712 |
Cost of components: ~$1,800–$2,800. This handles all typical full-time loads including induction cooking.
Specific scenarios
Weekend + campground hookups: If you mostly camp at sites with shore power, electrical needs drop significantly — a 100Ah battery and no solar may be all you need, with a simple shore power converter charger for the nights you're hooked up.
Full-time + heavy work setup: Remote workers running dual monitors and desktop PCs need 400Ah+ and 500–600W solar. Induction cooking twice a day on top of this pushes daily loads to 1,500Wh+.
Van life in the US southwest: Excellent sun means solar is reliable. 300W solar often produces 1,200Wh/day — self-sustaining for most full-time loads.
Full-time in the Pacific Northwest or winter: Fewer sun hours. Solar underperforms. DC-DC charger while driving becomes the primary recharge. Ensure you drive frequently enough or supplement with shore power.
Upgrade path
Design your initial build to be upgradeable:
- Install bus bars rather than wiring directly to battery — adding a second battery later is easier
- Leave space in the fuse block for additional circuits
- Size your solar charge controller for more panels than you initially install (a 40A controller with 200W of panels can accept 400W later)
Related
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Roam Wired turns campervan research into practical plans. We publish transparent guidance, a free electrical design tool and marketplace resources for UK and US van builders.
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