Campervan electrics in one cup of tea

Campervan electrics often feel like a dark art, but they are essentially two separate systems that occasionally shake hands. Understanding the basics doesn't require an engineering degree—just the time it takes to finish a cup of tea. As we move into 2026, the shift toward lithium power and high-efficiency solar has made off-grid living more accessible than ever.

1. Two Voltages, Two Jobs

Your van operates on a dual-voltage system. Think of them as the 'Off-Grid' system and the 'Home-from-Home' system.

• 12V (The Leisure Battery): This is the heart of your van. It runs the LED lights, water pump, diesel heater ignition, and USB ports. It is always 'on' as long as the battery has charge.
• 230V (The Hook-up): This is the same voltage as your house. It only works when you are physically plugged into a bollard at a campsite (Electric Hook-Up or EHU). This runs your standard 3-pin sockets and heavy appliances like microwaves or hair dryers.

2. The Battery Bit People Get Wrong

A leisure battery is not a magical well; it is a bucket of energy. Capacity is measured in Amp Hours (Ah). However, the usable capacity depends on the battery chemistry:

• Lead-Acid/AGM: You should only use 50% of the stated capacity. A 100Ah battery only gives you 50Ah of real-world use before voltage drops too low.
• Lithium (LiFePO4): You can safely use up to 90-95% of the capacity. They are lighter and more efficient for modern builds like those from Vanworx, CMC Reimo, or Kaktus Adventure Vans.

Pro Tip: If your van has a large inverter (to run a coffee machine or laptop), it will drain a standard battery incredibly fast. Always check your setup using our Campervan Conversion Checker to ensure your battery matches your appliances.

3. The Fridge Reality Check

Fridges are the biggest power consumers in a campervan. There are two main types:

• Compressor Fridges (12V): Like a home fridge but smaller. They are efficient and stay cold even in hot weather, but they rely entirely on your leisure battery. These are standard in models like the Volkswagen California.
• Absorption Fridges (3-Way): These can run on Gas, 12V (while driving), or 230V (on hook-up). They are great for long off-grid stays if you have plenty of gas, but they are less efficient in high ambient temperatures and require professional gas safety checks.

4. A Low-Stress Upgrade Order (2026 Refresh)

If you are looking at used campervans and want to improve the electrics, follow this logical sequence:

1. Monitor First: Install a high-quality battery monitor (shunt) so you actually know how much power is left.
2. Solar Power: A 100W-200W panel provides gentle daily top-ups. In 2026, many owners prefer rigid panels for efficiency or CIGS flexible panels for weight saving.
3. B2B Charger: A Battery-to-Battery charger ensures your leisure battery charges quickly and safely from the engine while you drive—essential for modern 'Smart Alternators' found in Euro 6 vehicles.
4. Inverter: Only add this last if you absolutely need 230V power while away from a campsite.

5. Safety and Compliance

In the UK, any 230V installation should be installed and certified to BS 7671 standards (specifically Section 721). Ensure your van has a Consumer Unit (RCD/MCB) to protect you from shocks and fires. When browsing Campervan Models, always ask to see the electrical sign-off for professional conversions.

Frequently Asked Questions

Can I charge my leisure battery while driving?

Yes, most modern vans use a B2B (Battery-to-Battery) Charger. Older vans might use a Split Charge Relay, but these are often insufficient for modern Euro 6 engines with smart alternators which require a specific charging profile.

How long will a 100Ah battery last off-grid?

Typically 1-2 days if running a compressor fridge, lights, and water pump. This can be extended significantly with 100W+ of solar power or by upgrading to Lithium (LiFePO4) which offers more usable depth of discharge.

Do I need an inverter?

Only if you want to use 3-pin domestic appliances (like a toaster or hair dryer) when not plugged into a campsite. Note that these draw massive amounts of current and require heavy-gauge wiring and high-capacity batteries.

Is a solar panel enough to keep my battery full?

In the UK summer, a 100W-150W panel can often keep up with basic 12V usage. In winter, the low sun angle and shorter days mean you will likely need a B2B charger or EHU to maintain charge.