Off-grid van electrical comes down to one equation: daily energy in must equal or exceed daily energy out. Here's what that means practically.
What "off-grid" actually demands
Off-grid means no shore power hookups — you rely entirely on solar, driving (via DC-DC charger), or a generator for recharging. The electrical system must be sized for your typical daily load plus enough buffer for cloudy days or low-mileage weeks.
Minimum viable off-grid system
For typical van life loads (fridge, laptop, phone, lighting, fan — no induction cooking):
| Component | Minimum spec | Why |
|---|---|---|
| Battery | 200Ah LiFePO4 | 2–3 days autonomy at 600Wh/day |
| Solar | 300W | Self-sustaining in moderate sun |
| MPPT charge controller | 30–40A at 12V | Matches 300–400W panel array |
| DC-DC charger | 30A (Renogy DCC30S or equivalent) | Alternator backup on driving days |
| Fuse/breaker | 200A main fuse | Sized for battery and inverter |
| Shunt/monitor | Victron SmartShunt | Know your actual state of charge |
This system costs roughly $1,200–$1,800 in components and handles most van life scenarios comfortably.
Scaling up for heavy use
If you run an induction cooktop, work from a desktop setup, or frequently camp in cloudy climates:
| Component | Upgraded spec |
|---|---|
| Battery | 300Ah LiFePO4 (or 2× 200Ah in parallel) |
| Solar | 400–600W |
| DC-DC charger | 40A (Victron Orion XS or Renogy DCC50S) |
| Inverter | 2,000W pure sine |
What drains a battery fastest
The two biggest loads in most van builds:
- 12V compressor fridge: 40–80Wh per day depending on ambient temp and thermostat setting. Highest single daily draw but spread over 24 hours.
- Induction cooking: 1,500–1,800W for 15–30 minutes = 375–900Wh per cooking session. Often the biggest single-event drain.
If you run induction cooking twice a day, you might need 800+ additional Wh beyond your baseline — which means more battery and solar than a non-cooking build.
Off-grid realities
Sunny weather: 300–400W solar generating 1,200–1,600Wh/day easily covers a 600–800Wh daily load. Battery stays topped up.
Overcast weather: 300W solar might produce only 200–600Wh. You draw down the battery. After 2–3 cloudy days, you're driving to recharge or plugging in somewhere.
Winter at northern latitudes: Fewer peak sun hours, panels may be snow-covered, and heating loads are higher. Many full-timers migrate south in winter or use a generator as backup.
Parking in the shade: Solar produces little or nothing. The DC-DC charger while driving becomes the primary recharge source.
Size for your worst-case week, not your best day
Design the system for a week of overcast weather, not a sunny July day at 40° latitude. A system that handles the bad week comfortably handles the good week effortlessly.
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Roam Wired
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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