How much does the electrical system for a camper van cost?

A basic 12V system (battery, solar panel, charge controller, wiring) costs between €500 and €1,500. With lithium battery, inverter and expanded system you're looking at €2,000 to €4,000. The biggest expense is the battery.

Can I install the electrics myself with no experience?

Yes, many first-time builders do this successfully. The key is a solid plan: calculate your consumption, choose the right wire gauges, protect everything with fuses and draw a diagram before you start. Use the free Electrical Planner so you don't miss anything.

How many solar panels do I need on my camper van?

That depends on your power consumption and where you travel. A rule of thumb: divide your daily consumption (Wh) by 3 (sun hours). At 400Wh per day you need roughly 130-150Wp. In Southern Europe you can get by with less, in Scandinavia you'll need more.

What's the difference between the Electrical Planner and the individual calculators?

The individual calculators (wire gauge calculator, battery calculator, solar calculator) each calculate a single component. The Electrical Planner combines everything in a 6-step workflow and delivers a complete plan: consumption overview, wire gauges, component list and wiring diagram.

12V or 24V: when should I choose 24V?

Choose 24V if you're building a large system (above 200Ah, with induction cooktop or AC). The advantages: thinner cables, less power loss, more efficient inverter. Disadvantages: fewer 24V appliances available, you'll need a DC-DC converter for 12V consumers.

Camper van wiring plan: from power budget to wiring diagram

The electrical system is the nervous system of your camper van build. A solid plan prevents fire hazards, saves money and ensures you can go off-grid without worries. But where do you start? In this guide we walk you through the 6 steps to plan your complete electrical installation — from first choices to a full wiring diagram.

Plan your electrics automatically

Electrical Planner→Cable calculator→Fuse calculator→

Step 1: Choose your system voltage — 12V or 24V?

The first decision is your system voltage. Most camper vans use 12V because it's simple and nearly all camper appliances run on 12V. But for larger systems (above 200Ah), 24V can be more efficient: cables can be thinner and you lose less power. 12V is the right choice if you're building a standard camper with lighting, fridge, USB charging and a water pump. 24V becomes interesting when you're planning a large system with induction cooktop, AC or heavy electrical consumers. Also choose your battery type: lithium (LiFePO4) is lighter, lasts longer and delivers more usable capacity than AGM or gel. The higher purchase price pays for itself in lifespan.

Step 2: Calculate your daily power consumption

Make a list of every electrical device in your camper van. Note the power rating (watts) and estimated daily usage (hours) for each. Multiply these for daily consumption in watt-hours (Wh). Example: LED lighting (10W x 5h = 50Wh), fridge (40W x 24h = 960Wh, but a compressor fridge runs about 30% of the time, so 288Wh), water pump (60W x 0.5h = 30Wh), phone charging (10W x 3h = 30Wh). Total: roughly 400Wh per day. Add 20% to your total for cable losses, inverter losses and unexpected usage. This gives you a safe margin.

Step 3: Calculate wire gauges and fuses

Every cable in your camper van must be thick enough for the current flowing through it. At 12V the current is much higher than you might expect: a 100W device draws over 8A at 12V. The correct wire gauge depends on three factors: the current (amps), the cable length (one way) and the maximum allowable voltage drop (usually 3-5%). The longer the cable and the more current, the thicker the cable must be. Every cable needs a fuse, as close to the battery (positive terminal) as possible. The fuse protects the cable, not the device. Choose a fuse that matches the maximum current rating of the cable, not the consumption of the device.

Step 4: Solar panels and charging strategy

To charge your batteries you need one or more charging sources. The most common combination is solar panels plus a B2B charger (charges while driving via the alternator). For solar panels: divide your daily consumption by the number of effective sun hours. In Northern Europe that's about 3-4 hours in summer, 1-2 in winter. At 400Wh daily consumption and 3 sun hours you need roughly 135Wp of panels. An MPPT charge controller extracts 20-30% more energy from your panels than a PWM controller. For panels above 100Wp, MPPT is almost always the better choice. Also consider shore power (230V/120V charger) for when you're at a campsite. This gives you three independent charging sources.

Step 5: Choose and size your components

With your consumption, cables and charging sources determined, you can choose your components: Battery: choose a capacity that covers at least 2 days of consumption. At 400Wh per day that's 800Wh, or a 65Ah lithium battery (12.8V x 65Ah = 832Wh). With AGM you need to double this because you can only discharge to 50%. Inverter: only needed if you use 230V/120V appliances. Choose a pure sine wave inverter and size it for the heaviest device you want to run simultaneously. Fuse box: a central distribution point for all your circuits. Use a busbar for positive and one for negative, with individual fuses per circuit. Switches: a main switch at the battery and switches per circuit for convenience and safety.

Step 6: Draw your wiring diagram

Before you cut a single wire, draw a complete wiring diagram. This diagram shows all components, cables, fuses and connections. It's your blueprint for the installation and indispensable when troubleshooting later. A good diagram includes: the battery with main fuse, the distribution point (busbar/fuse box), all circuits with wire gauge and fuse rating, the charging sources (solar panel, B2B, shore power) and optionally an inverter. Keep your diagram in a safe place inside the camper van. When you want to add something later or trace a fault, it's worth its weight in gold.

Plan your electrics automatically

The Electrical Planner automatically calculates your consumption, wire gauges, solar panels and components. You get a complete wiring diagram in 6 steps.

Electrical Planner→Cable calculator→Fuse calculator→

Frequently asked questions

How much does the electrical system for a camper van cost?: A basic 12V system (battery, solar panel, charge controller, wiring) costs between €500 and €1,500. With lithium battery, inverter and expanded system you're looking at €2,000 to €4,000. The biggest expense is the battery.
Can I install the electrics myself with no experience?: Yes, many first-time builders do this successfully. The key is a solid plan: calculate your consumption, choose the right wire gauges, protect everything with fuses and draw a diagram before you start. Use the free Electrical Planner so you don't miss anything.
How many solar panels do I need on my camper van?: That depends on your power consumption and where you travel. A rule of thumb: divide your daily consumption (Wh) by 3 (sun hours). At 400Wh per day you need roughly 130-150Wp. In Southern Europe you can get by with less, in Scandinavia you'll need more.
What's the difference between the Electrical Planner and the individual calculators?: The individual calculators (wire gauge calculator, battery calculator, solar calculator) each calculate a single component. The Electrical Planner combines everything in a 6-step workflow and delivers a complete plan: consumption overview, wire gauges, component list and wiring diagram.
12V or 24V: when should I choose 24V?: Choose 24V if you're building a large system (above 200Ah, with induction cooktop or AC). The advantages: thinner cables, less power loss, more efficient inverter. Disadvantages: fewer 24V appliances available, you'll need a DC-DC converter for 12V consumers.