Knowing your real daily energy use is the foundation of sizing a van electrical system. Here are real-world numbers for different van life scenarios.
Typical daily watt-hour usage by lifestyle
Minimal weekend build (250–400Wh/day)
| Load | Watts | Hours | Wh/day |
|---|---|---|---|
| 12V compressor fridge | 45W avg | 24h duty cycle | 55Wh |
| Phone charging | 15W | 2h | 30Wh |
| LED lighting | 15W | 3h | 45Wh |
| Misc USB / small devices | 10W | 4h | 40Wh |
| Total | ~170Wh |
This covers a basic weekend build with a fridge and phone. A 100Ah LiFePO4 battery easily handles 2–3 days without recharging.
Full-time van life without cooking (500–700Wh/day)
| Load | Watts | Hours | Wh/day |
|---|---|---|---|
| 12V compressor fridge | 50W avg | 24h | 65Wh |
| Laptop (work from van) | 65W | 5h | 325Wh |
| Phone + tablet | 25W | 2h | 50Wh |
| Fan (MaxxAir Deluxe) | 25W avg | 8h | 200Wh |
| LED lighting | 20W | 3h | 60Wh |
| Total | ~700Wh |
This is a common full-time digital nomad setup. A 200Ah LiFePO4 (160Ah usable) paired with 300W+ solar handles this comfortably.
Full-time with induction cooking (900–1,200Wh/day)
| Load | Watts | Hours | Wh/day |
|---|---|---|---|
| Above loads | — | — | 700Wh |
| Induction cooktop (1,500W) | 1,500W | 30 min | 750Wh |
| Electric kettle | 1,200W | 10 min | 200Wh |
| Total | ~1,200–1,500Wh |
Cooking electrically is by far the largest single addition. One induction cooking session adds 375–750Wh. This lifestyle needs 300Ah+ battery and 400–600W solar to stay energy-positive off-grid.
High-power van (1,500–2,500Wh/day)
- Desktop PC workstation: 150W × 8h = 1,200Wh
- Dual-monitor setup: 50W × 8h = 400Wh
- Multiple cooking sessions, air conditioning bursts
These builds typically run 400Ah+ LiFePO4 and 600W+ solar, or supplement with a generator.
Hidden draws to account for
- Inverter idle draw: 15–30W × 24h if left on all day = 360–720Wh/day just standing by → switch it off when not in use
- DC-DC charger standby: 1–3W when not charging, negligible
- 12V fridge compressor cycling: Varies 2–4× based on ambient temperature; a fridge in a hot van works much harder
- Diesel heater: 8–25W while running (glow plug startup is brief high draw)
Quick calculator formula
Daily Wh = Σ (device watts × daily hours)
+ 20% buffer for losses and hidden draws
Once you have your daily Wh number:
- Battery (Ah): Daily Wh ÷ 0.8 (DoD) ÷ 12V
- Solar (W): Daily Wh ÷ 0.85 (efficiency) ÷ 4 (peak sun hours)
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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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