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The Ultimate Guide to Campervan Power in the UK

Whether you’re heading out for a day, a weekend, a couple of weeks, or living full-time in your van, reliable power makes all the difference. From charging phones and laptops to keeping a fridge running or powering a heater in winter, your electrical setup is the beating heart of vanlife.

This article explains everything, from simple USB power banks to full lithium + solar installations, with UK-specific safety advice and recommended kit.


Icons of a battery, solar panel, and campervan on a blue and green background. Text reads "The Ultimate Guide to Campervan Power in the UK."


Safety First

Campervan electrics are not a place for shortcuts:

  • 12V fires happen if cables are undersized or unfused.

  • 230V mains can kill if installed incorrectly.

  • In the UK, follow BS 7671 (Section 721) and EN 1648.

Golden rules:

  • Fuse every positive feed near the battery.

  • Keep voltage drop ≤3% on critical loads.

  • Fit RCD + MCB for any EHU.

  • Never PME earth bond your van body.

  • Lithium batteries need BMS and low-temp protection.

  • Label, document, and sketch your system.


The Basics: Voltage, Current, Energy

  • Watts (W) = Volts × Amps

  • Watt-hours (Wh) = W × hours


Example:100 Ah × 12 V = 1,200 Wh (1.2 kWh)

  • AGM usable: ~600 Wh

  • LiFePO₄ usable: ~1,000 Wh


Always add ~20% for losses.


Power Options by Trip Length

Trip Style

Best Fit

Typical Needs

Day trips

Power bank / portable station

Phones, cameras, laptop

Weekends

100 Ah lithium + 30A DC-DC

Lights, fridge, devices

1–2 weeks

200 Ah lithium + 30–50A DC-DC + 300–400 W solar + inverter

Fridge, heater, laptops

Full-time

300–400 Ah lithium + 50–60A DC-DC + 400–600 W solar + 1–2 kW inverter + EHU

Year-round, full comfort

Core System Components

Batteries

  • AGM: budget-friendly, sealed, ~50% usable.

  • LiFePO₄: light, 80–90% usable, long cycle life.


Alternator Charging

  • VSR (split charge relay): okay for old vans with lead-acid.

  • DC-DC charger: essential for modern alternators and lithium.


Solar Power

  • 100 W panel in UK: 300–500 Wh/day in summer, 30–150 Wh/day in winter.

  • Rigid: durable; flexible: discreet but short-lived; portable: great in shade.

  • Always use MPPT for >150 W systems.


Inverters

Convert 12V DC to 230V AC. Always pure sine.

  • 300–600 W: laptops, chargers.

  • 1000–1500 W: small kitchen kit.

  • 2000 W+: heavy loads, big lithium bank only.


Electric Hook-Up (EHU)

  • 16A blue IEC 60309 connector (UK standard).

  • Needs RCD + MCB inside van.

  • Use a mains charger for your leisure battery.


Wiring & Protection


Worked Gear Bundles

Day-tripper

Weekender

Holidaymaker (1–2 weeks)

Full-timer


Campervan Power FAQs

Q: Can I just use my starter battery? No. You’ll risk being stranded. Always fit a leisure battery.

Q: How much solar do I need?100 W panel = 300–500 Wh/day in summer, 30–150 Wh/day in winter. Aim for 300–400 W if you want year-round reliability.

Q: Is lithium worth it? Yes. More usable energy, longer life, lighter. Higher upfront cost but cheaper per cycle.

Q: Can I run a microwave? Yes, with at least 200 Ah lithium + 1500 W inverter. Expect heavy drain.

Q: Do I need an inverter? Only if you must run 230V appliances. Many manage with 12V + USB-C.

Q: What size cable should I use?

  • 1.5 mm²: lights/USB (≤5 A)

  • 4 mm²: fridge (≤20 A)

  • 10 mm²: DC-DC charger (≤30 A)

  • 35–50 mm²: 1000 W inverter (~90 A)


Troubleshooting Common Campervan Power Problems

Battery drains too fast

  • Cause: undersized bank, inverter idle draw, inefficient fridge.

  • Fix: upgrade battery, switch inverter off, add solar.

Inverter trips

  • Cause: appliance too powerful, undersized cables, low battery.

  • Fix: check load, fit thicker cables, recharge.

Solar not charging

  • Cause: miswiring, shade, wrong controller settings.

  • Fix: check wiring, clean panel, reprogram controller.

Fridge flattens battery

  • Cause: using 12V cool box instead of compressor fridge.

  • Fix: upgrade to compressor fridge, add more battery.

RCD trips on hook-up

  • Cause: damp socket, faulty appliance, bad earthing.

  • Fix: dry/replace cables, test appliances one by one, check consumer unit.


Seasonal Tips for Campervan Power in the UK

Summer

  • Solar output is strong, 200 W can give 1 kWh/day.

  • Protect lithium from heat (>45 °C).

  • Use 12V fans, not inverter-powered fans.

  • Ventilate fridges well.

Winter

  • Solar weak, 100 W panel may only yield 30–150 Wh/day.

  • Plan for alternator charging or EHU.

  • Protect lithium below 0 °C (heated batteries or insulated install).

  • LEDs matter more with long nights.

All-Year

  • Combine solar, DC-DC, and EHU for flexibility.

  • 300–400 W solar is the UK sweet spot.

  • Carry a spare USB bank or small power station.

  • Fit a battery monitor (e.g. Victron SmartShunt).


Campervan Power Bundles infographic with options: Day-tripper, Weekender, Holidaymaker, Full-timer. Details lithium batteries, solar panels.

Final Thoughts

Think about how you travel:

  • Day trips? Keep it simple.

  • Weekends? A 100 Ah lithium + DC-DC is perfect.

  • Holidays? Add solar and an inverter.

  • Full-time? Build once, build right.


With the right gear and safe installation, you’ll enjoy freedom from flat batteries, and more time enjoying the road, the views, and the adventure.


Thanks for reading and please share!

If this guide helped you plan your campervan power setup, we’d love it if you shared it with a mate, posted it in your favourite vanlife group, or linked it from your build diary. Your shares help keep VanLife.uk independent and free for everyone.


Got a tip we missed or a question about your own build? Drop a comment and we’ll do our best to help. Safe travels and happy tinkering! 🚐💨

 
 
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