DIY camper electrics guide
The house battery — the heart of your installation
When building a camper van, the electrical installation is the part most people struggle with. Not because it's so complicated, but because you haven't grown up with it and the terms are unfamiliar. Yet, the basic principle is surprisingly simple: you have one leisure battery, and you live off that battery.
Everything you use in your camper van draws power from that battery. The refrigerator that runs day and night. The LED lighting you switch on in the evening. The water pump that kicks in when you open the tap. Your laptop that you use in the evening. All these devices draw power from the same battery. The trick is to ensure that enough power also comes in – so that your battery is never empty when you need it.
How large that battery needs to be depends on what you consume and how long you want to be able to stay without an external power supply. A weekend trip to a campsite with shore power requires something completely different than a month-long trip without a fixed residence. And that's precisely why it pays to calculate this carefully beforehand – a too-small battery is one of the most common mistakes made by DIY builders.
Calculate consumption — start here
Before you buy a single component, it's wise to calculate your daily consumption. Write down all the appliances you want to use in your camper, look up how many watts they consume, and estimate how many hours a day you use them. Multiply these two numbers — that gives you the consumption in watt-hours (Wh).
To give you an idea of realistic daily values: lighting costs an average of 30Wh per day, charging a phone 15Wh, a tablet 30Wh, a Wi-Fi access point 10Wh, Starlink Mini 40Wh. The refrigerator is by far the biggest consumer at 400Wh per day — a compressor refrigerator draws 30–60W when the compressor is running, but it's only on 10–30% of the time, resulting in that daily average. A coffee maker consumes 120Wh, induction cooking 500Wh, a fan 40Wh, a gas boiler or diesel heater only 15Wh for operation, an electric boiler 225Wh, a water pump 20Wh, charging a laptop 50Wh, a television 35Wh, a game console 200Wh, charging a drone 20Wh, and charging an e-bike battery 500Wh.
Add up everything you expect to use daily, and you'll have your daily consumption in Wh. Take two to three times that number as a guideline for the required battery capacity — this extra margin is necessary because you should never fully discharge a battery, and because there are always days with less sun or more consumption than planned. On our product page, you'll find an interactive consumption calculator — check off your appliances, and you'll immediately see which package suits your situation.
Which battery type suits you?
There are three types of leisure batteries in RVs: semi-traction, AGM, and lithium (LiFePO4). They differ significantly in price, usable capacity, weight, and lifespan.
Semi-traction is the cheapest type — but also the most limited. A semi-traction battery should only be discharged by 25%. So, from a 100Ah semi-traction battery, you effectively only have 25Ah available. Moreover, semi-traction has the strongest Peukert effect. For serious use in an RV, we do not recommend semi-traction.
AGM (Absorbed Glass Mat) is the classic and proven choice. Virtually maintenance-free, resistant to shocks and vibrations, and widely available. The disadvantage: it should not be discharged deeper than 50%. From a 100Ah AGM, only 50Ah is usable.
Lithium (LiFePO4) is the most modern choice. The full capacity is available — from a 100Ah lithium battery, you really use 100Ah. Lithium is up to three times lighter than AGM, lasts 2000–3000 charge cycles compared to 300–500 for AGM, and has virtually no Peukert effect. The purchase price is higher, but over its full lifespan, lithium is more economical in most cases.
Most lithium batteries in our range have a built-in BMS. A lithium battery with a BMS is a so-called drop-in replacement — in most cases, you can charge it with a lead-acid charging profile, because the BMS regulates the incoming charging current and switches off charging as soon as the battery is full. Nevertheless, a specific LiFePO4 charging profile is always preferred: it ensures a fuller charge and maximum lifespan. So, always use it if your charging equipment supports it.
The choice of your battery type also has implications for the rest of your installation. If you choose lithium, you will need an MPPT charge controller with a lithium profile, a DC-DC charger that supports lithium, and a battery charger with a lithium profile. View our range of batteries.
Charging method 1: solar panels
Solar panels are the primary charging method for most camper builders, and rightly so. They are quiet, maintenance-free, require no fuel, and give you a great degree of freedom — you are not dependent on a campsite or an electrical outlet. The principle is simple: the panel on your roof generates direct current from sunlight, which goes to your leisure battery via a charge controller. The charge controller is essential in this — without a charge controller, your battery would quickly be damaged by overcharging.
There are two types of charge controllers: PWM and MPPT. A PWM controller switches on as soon as the panel voltage exceeds the battery voltage and is the cheaper option. In a small system with one panel and an AGM battery, the difference with an MPPT is practically nil. An MPPT controller is the right choice as soon as you work with two or more panels, have higher panel voltage, or use a lithium battery. With two panels in series, the gain compared to PWM is realistically up to 30% due to the higher input voltage. With Victron MPPT controllers, an input voltage of 5V above the battery voltage is required to switch on — once active, it extracts the maximum energy from your panels. View our charge controllers.
In the Netherlands, you have an average of 3–4 peak sun hours per day in the summer. In winter, the yield is 7 to 8 times lower — due to the low sun angle AND because panels on a camper lie flat instead of at the optimal angle, which causes more reflection in winter. A setup that provides ample power in summer can barely contribute anything in winter. If you want to be self-sufficient in autumn and winter, combine with driving charge via a DC-DC charger or rely on shore power at the campsite. View our charge controllers and solar panels.
Charging method 2: charging while driving
While driving, your van's alternator charges the starter battery. You can also extend this charging current to your house battery.
For older vehicles (Euro 4 and older) with a conventional alternator and an AGM house battery, a simple relay or battery isolator (VSR) may suffice. The relay automatically switches on as soon as the alternator supplies sufficient voltage, connecting the starter and house batteries. As soon as the engine stops, the relay disconnects the connection again – preventing the house battery from draining the starter battery. Please note: this is not future-proof – if you switch to lithium or a newer vehicle, you will still need a DC-DC charger.
For Euro 5 or 6 vehicles or with a lithium house battery, you always need a DC-DC charger. Newer vans are equipped with a smart alternator that actively reduces the charging voltage as soon as the starter battery is full – to save fuel. A relay detects this low voltage as "not charging" and does not switch on. Result: your house battery barely charges, even though the engine is running. With lithium, you also want to be able to limit the charging current – a high influx from the starter battery is undesirable – and electrically disconnect the starter battery so that it can never be drained. A DC-DC charger does all of this automatically. Check out our DC-DC chargers.
Charging method 3: shore power
At a campsite or in a marina, you can connect to the fixed 230V power grid. For most camper builders, the Victron MultiPlus inverter/charger is the preferred choice for this. The MultiPlus combines an inverter and a battery charger in one device, with a built-in transfer switch.
The big advantage over a separate inverter plus a separate battery charger is that all 230V sockets in your camper are connected to one circuit. With a separate inverter, you have two separate circuits—the sockets on shore power and a separate socket for the inverter—and you have to keep track of which socket you can use at which moment. With the MultiPlus, you never have to think about that again: it automatically regulates whether the power comes from shore power or from the battery, and switches over within milliseconds without your devices noticing anything. The MultiPlus also has a PowerAssist function—if the shore power connection is limited, it can deliver extra power from the battery to handle peak loads. View our inverter/chargers.
For a safe connection, you need a CEE plug and a consumer unit with a residual current device (RCD). The RCD is mandatory for every 230V system and required at almost all campsites.
The full picture – everything summarized
Your house battery is the central hub. Power flows out to all your consumers. Power comes in via three routes: solar panels via the charge controller, the alternator while driving via a DC-DC charger, and shore power via the distribution board and the MultiPlus. All three can be active simultaneously.
Size the system so that the average daily income is balanced with consumption. A margin of 20–30% extra incoming power is comfortable for bad weather days or unexpectedly higher consumption.
Are you ready? Check out our ready-made packages on the product page — the consumption calculator will show you exactly which package suits your situation. Would you prefer us to figure it out for you? Then request a custom quote — we are happy to assist you.