How much power do you need in a van?
Off‑grid living, sized properly — not copied from your mate’s build.
Skip the guesswork. This guide shows you exactly how to size your van power system so you never run out of battery, freeze without heating, or spend money on capacity you’ll never use.
We’ve tested this on real vans. We’ve lived it. Here’s what actually works.
Every figure on this page is real measured load from UK vans, not spec‑sheet fantasy.
Why most van dwellers get power sizing wrong
The biggest mistake isn’t what you think. It’s this: you copy someone else’s setup.
Your mate’s van has a 2,000Wh battery and it’s fine. You buy the same one. Six months later you’re freezing because you’re running heating 14 hours a day instead of his 4, and charging two laptops instead of his one.
Same battery. Completely different van. Completely different outcome.
Every van power system is unique. Your power needs depend on:
- What devices you’re running — fridge, heater, laptop, lights, water pump, inverter
- How long you run them daily — 4 hours or 14 hours?
- Your location — sunny Spain or cloudy Scotland?
- Your season — summer or winter?
- Your weather — 8 hours of sun, or 2?
Get any of these wrong and your system fails. You either buy too much capacity — wasting money — or too little, and run out of power when you need it most.
How to calculate your van power needs
Stop overthinking this. You need three numbers.
How much power each device draws
Check the label or spec sheet — laptops, fridges and heaters are all rated in watts.
How long you use it each day
Be honest about real usage, not best‑case. A heater in winter can run 14 hours, not 4.
Watt‑hours per day
Multiply the two together. This is the number your battery and solar have to cover.
Real van power consumption (UK‑based living)
What you actually draw in a UK van setup — not marketing fantasy.
| Device | Daily draw | Hours / day | Notes |
|---|---|---|---|
| 12V compressor fridge | 300–500Wh | 24h (cycles) | Always on, compressor cycles. Winter = less draw. |
| Laptop + phone charging | 150–250Wh | 6–8h | MacBook Pro ≈ 100W, phone charger ≈ 20W. |
| Space heater / fan heater | 400–1,000Wh | 6–14h (winter) | Your biggest draw. Winter is a killer for battery. |
| LED lights | 150–250Wh | 10–14h | 6–10 LED strips plus overhead lights. |
| Water pump (hot water) | 75–150Wh | 2–4h | Shower and washing dishes. |
| Entertainment (TV / monitor) | 200–400Wh | 4–6h | Evening viewing. |
| Air compressor / power tools | 300–800Wh | 1–2h (occasional) | High spike loads. Plan weekly, not daily. |
Winter van power calculation — Scotland
You’re parked at a Scottish campsite in December. Here’s your actual daily load.
- Fridge (24h) 400Wh
- Laptop / work (8h) 200Wh
- Space heater (12h) — biggest consumer 720Wh
- Lights (14h) 200Wh
- Water pump (3h) 100Wh
- TV / entertainment (5h) 250Wh
- Daily total 1,870Wh
Daily total plus a 20% safety buffer for cloudy days and battery inefficiency losses — this is your real baseline to size against.
How to choose the right power station size
Here’s the rule that separates people who succeed from people who freeze:
Buy a battery rated for 1.5–2× your daily power consumption.
You can’t use 100% of it
Even good lithium batteries are only 60–80% usable. Draining one fully kills its lifespan.
Cloudy days exist
Solar won’t generate full power. You need enough stored energy to coast through 1–2 grey days.
Batteries age
After 2–3 years you’ll lose 10–20% capacity. Better to start with headroom.
For a 2,244Wh daily need, you need 3,500–4,500Wh total capacity. That sounds huge — but winter heating makes it necessary.
Best portable power stations for UK vans
Read the full comparison: Best Power Station for Vans →
Jackery 1000
Budget- Summer camping, light use, or backup battery
- Undersized for winter van living or heating loads
EcoFlow Delta Pro
Best all‑rounder- Full‑time living, winter heating, fast 1‑hour recharge to 80%
- Budget builds or small vans short on roof space
Bluetti AC500
Premium- AC loads or several devices running simultaneously
- Overkill for most single‑occupant van builds
Goal Zero Yeti 1500X
Budget alternative- Smaller vans, budget builds, or a secondary backup
- Still short of a true winter full‑time setup
Next: Once you’ve sized your battery, you’ll need solar to recharge it. Solar Power Van Setup Guide →
How much solar do you actually need?
A 100W panel doesn’t generate 100Wh a day. Capacity ≠ daily output. Full setup: Solar Power Van Setup Guide →
Per 100W panel — 4–5 peak sun hours.
Per 100W panel — 2.5–3.5 peak sun hours.
Per 100W panel — 0.8–1.5 peak sun hours. Brutal.
For a 2,244Wh daily need: 100–150W solar covers most summer days. In winter you need 400W+ solar — and even then, plan on mains charging or gas heating as backup.
Realistic van setup: 200–300W solar + 3,500Wh battery + gas heating for winter. That’s the winning combo tested in real UK conditions.
Common van power system mistakes
01 Undersizing the battery by half
You see a 1,000Wh battery for £900, get excited, buy it. Your actual need is 2,000Wh. By 2pm you’re dead.
02 Running mains‑voltage appliances constantly
A 2,000W kettle drains a 3,000Wh battery in 1.5 hours. Microwaves, heaters and power tools kill batteries fast.
03 Ignoring seasonal load changes
Your summer setup (500Wh/day) is not your winter setup (2,000Wh/day). Treat them as different systems.
04 Solar without enough battery to store it
You install 300W solar but only have a 1,000Wh battery. On sunny days you waste 60% of your output.
Use our van power calculator
Stop guessing. Input your devices and hours per day — get a precise recommendation in 60 seconds.
- Your exact daily watt‑hour consumption
- Recommended battery size, with a 20% safety buffer
- Top power station models that fit your needs
- Comparison of price versus capacity
The van power system you actually need
Summer‑only camping
100–150W solar
1,000Wh battery
12V fridge
Full‑time UK van, with winter
200–300W solar
3,500–4,000Wh battery
Gas heating backup
Premium full‑time, all‑electric
400W+ solar
5,000–7,000Wh battery
No gas backup
Most van dwellers land in the middle option — the sweet spot of capability and cost.
Get the calculation right first
- Calculate your real daily consumption.
- Multiply by 1.5–2× for your battery capacity target.
- Add solar to cover 60–80% of that on an average day.
- Plan for winter, or accept mains charging as a backup.
Get this foundation right and your van runs reliably for years. Get it wrong and you’re cold, frustrated, and out thousands of pounds.
More van power guides
How Much Power Do You Need in a Van?
The full method — device wattage, daily hours, and a worked winter example.
Read the guide → ComparisonBest Power Station for Vans
Jackery, EcoFlow, Bluetti and Goal Zero, tested against real UK loads.
Read the guide → Setup guideSolar Power Van Setup
How much solar you actually generate per season, and how to size your array.
Read the guide →