Work out exactly what battery size and solar setup you need — before you spend a penny on kit.
The number one mistake people make before starting van life is either buying way too much power capacity — or way too little. This guide helps you figure out exactly what you need, based on how you actually live.
The honest truth is that your power needs in a van depend almost entirely on two things: what devices you run every day, and how much of that time you spend in the sun. Get those two numbers right and everything else falls into place.
This isn't a guide full of complicated electrical theory. It's a simple, practical walkthrough — the same process I wish I had used before I built Sioux.
Work through it section by section. By the end you will have a clear picture of what battery capacity, solar wattage, and setup level suits your van life — whether that's a plug-and-play Jackery or a full 12V lithium system.
Before looking at numbers, be honest with yourself about how you plan to use your van. Your power needs are completely different depending on your lifestyle.
You use the van for camping trips and getaways. You're not working from the van. You're happy plugging in at campsites when you need to. You want power for phone charging, a light, maybe a small fan.
You spend weeks or months in the van at a time. You might do some work from the van — emails, light laptop use. You want to run a cool box or mini fridge, charge camera gear, have good lighting.
The van is your home. You work from it — video editing, calls, content creation. You run a compressor fridge 24/7, charge all your camera batteries, maybe run a hair dryer occasionally. You need reliable power every single day regardless of weather.
Every electrical device uses power measured in watts (W). The longer you run it, the more watt-hours (Wh) it consumes. The simple formula is:
e.g. 50W laptop × 4 hours = 200Wh used
Here are the real-world power draws for the most common van life devices. Use these to calculate your typical daily total:
| Device | Typical Draw | 4hrs daily | 8hrs daily |
|---|---|---|---|
| MacBook / Laptop | 30–65W | 120–260Wh | 240–520Wh |
| Phone charging | 10–18W | 10–20Wh (1–2 charges) | — |
| Compressor fridge (12V) | 30–50W average | Runs 24/7: 360–600Wh/day | — |
| LED lighting (van) | 5–15W | 20–60Wh | 40–120Wh |
| Camera battery charger | 10–25W | 40–100Wh | — |
| Small fan (12V) | 10–25W | 40–100Wh | 80–200Wh |
| Diesel heater (fan only) | 10–25W | 40–100Wh | 80–200Wh |
| Portable speaker | 5–15W | 20–60Wh | — |
| Electric blanket (low) | 40–60W | 160–240Wh | — |
| Hair dryer ⚠️ | 1000–2000W | 500–1000Wh for 30 mins! | — |
| Kettle (mains) ⚠️ | 1500–3000W | 250–500Wh per boil | — |
Hair dryers, mains kettles, toasters, and fan heaters are absolutely not practical for off-grid van life. Switch to a 12V travel kettle (draws ~100W), gas hob, and air-dry your hair. These swaps alone can save you 500–1000Wh a day.
At roughly 690Wh per day, a 100Ah lithium battery (1200Wh usable) gives me nearly two full days of power with no sun at all. On a normal sunny day in Europe, my solar panels more than cover this — and I stay at 100% charge most of the time.
Once you know your daily Wh figure, choosing a battery size is simple. The golden rule is to have at least 2 days of power stored — so if you get two cloudy days in a row, you're not dead in the water.
Daily Wh × 2 = Minimum battery capacity you need
e.g. 500Wh daily use × 2 = 1000Wh minimum battery (roughly 80–100Ah lithium)
| Daily Use | Min Battery Size | Best Setup | Van Lifer Type |
|---|---|---|---|
| Under 200Wh | 300–500Wh | Jackery 300 or 500 | Weekend warrior |
| 200–400Wh | 500–800Wh | Jackery 1000 or 50Ah lithium | Part-timer, no fridge |
| 400–700Wh | 800–1400Wh | Jackery 1000 Pro or 100Ah lithium | Part-timer with fridge |
| 700–1000Wh | 1400–2000Wh | 100–150Ah lithium + Victron | Full-timer, content creator |
| 1000Wh+ | 200Ah+ lithium | Full 12V system, 300–400W solar | Full-timer, heavy user |
| Type | Cost | Usable Capacity | Weight | Best For |
|---|---|---|---|---|
| Jackery (LiFePO4) | £300–£1000 | 90% usable | Light | Beginners, no wiring |
| 12V Lithium (LiFePO4) | £200–£600 | 80–90% usable | Medium | Full builds, full-timers |
| AGM Lead Acid | £80–£200 | 50% usable only! | Heavy | Budget, short trips only |
AGM (lead acid) batteries are cheap but you can only use 50% of their rated capacity before damaging them. A "100Ah AGM" battery gives you only 50Ah of usable power. A 100Ah lithium gives you 80–90Ah. Don't be fooled by the lower price tag.
Your solar panels need to replace what you use each day, ideally with a bit to spare. In summer in Southern Europe, this is easy. In winter in the UK, it's genuinely hard.
Daily Wh ÷ average sun hours = Solar watts needed
e.g. 700Wh ÷ 4 hours sun = 175W of solar panels minimum
In the UK in winter: 700Wh ÷ 2 hours = 350W minimum
| Location / Season | Usable Sun Hours | For 500Wh daily | For 700Wh daily |
|---|---|---|---|
| Spain / Summer | 5–7 hours | 75–100W | 100–140W |
| France / Summer | 4–6 hours | 85–125W | 115–175W |
| UK / Summer | 3–5 hours | 100–165W | 140–230W |
| UK / Winter | 1–2 hours | 250–500W | 350–700W ⚠️ |
This is why people travelling Europe full-time tend to follow the sun south in winter — it simply isn't practical to survive on solar alone in a UK winter without enormous amounts of panels. That's when a DC-to-DC charger (charging from the alternator while you drive) becomes really important.
I spent a winter in the UK thinking 100W of panels would be enough. I was wrong. Since moving south every October, my battery stays full almost every day. The sun really is the answer.
— Bex Rae HartAlmost every van life power setup falls into one of two categories. Here's the honest comparison:
How it works: You buy a Jackery, plug solar panels into it directly, and plug your devices into it. That's it. No wiring, no fuses, no technical knowledge needed.
Best for: Weekend warriors, part-timers, people who want to start van life without committing to a full electrical build, and anyone who doesn't want to touch wires.
Limits: You can't run high-draw AC appliances for long. Jackery batteries are harder to expand. If you need more power you buy a second unit.
How it works: A 12V lithium leisure battery is wired into your van. A Victron MPPT solar controller manages the solar input. A Victron DC-to-DC charger tops it up from the alternator. An inverter converts 12V to 240V for your devices.
Best for: Full-timers, people doing a proper van conversion, content creators who need reliable power daily regardless of weather.
Limits: More complex to install — ideally get a professional to check the wiring. Higher upfront cost. Permanent installation.
Start with a Jackery if you're not sure yet. It's not "settling" — it's smart. You'll quickly learn what you actually use, what you wish you had, and what you never needed. Then if you want to upgrade to a full 12V system later, you'll know exactly what size to build. I know van lifers running Jackery setups full-time in Europe — it absolutely works.
| You Are... | Daily Use | Battery | Solar | System |
|---|---|---|---|---|
| Weekend warrior | Under 200Wh | 300–500Wh | 100W | Jackery 300/500 |
| Part-timer, no fridge | 200–400Wh | 500–800Wh | 100–200W | Jackery 1000 |
| Part-timer, with fridge | 400–700Wh | 800–1400Wh | 200W | Jackery 1000 Pro or 100Ah lithium |
| Full-timer, remote worker | 700–1000Wh | 100–150Ah lithium | 200–300W | 12V system + Victron |
| Full-timer, heavy user | 1000Wh+ | 200Ah+ lithium | 300–400W | Full 12V + DC-to-DC |
Once you know your system size, download my other free guides: Van Life Solar Power Made Simple (Jackery setup) and 12V Lithium + Victron Setup Guide (coming soon) at bexraehart.com/free-guide
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