In the last six parts of our blog series, you've already learned all the important basics about autonomous power supply in vehicles – from power requirements and battery types, solar technology and inverters to safe charging options and the correct wiring. In this final part, we summarize the key points for you and provide concrete tips for calculating costs, as well as the question: Do it yourself or have a specialist install it?
Whether you're traveling with a van on the weekends, living full-time in a van, or simply want to be more independent in your motorhome – with a cleverly planned system, you'll be self-sufficient, safe, and prepared for every travel situation.
Your power needs – the starting point for every planning
Before you get into the technology, you should know how much electricity you actually consume. The easiest way to do this is to make a list of all the devices you plan to use daily – including their power consumption (in watts) and usage time (in hours). This will give you your daily consumption in watt-hours (Wh).
Example consumption for everyday camper use:
- LED light (10 W, 5 h): 50 Wh
- Cooler (40 W, 12 h): 480 Wh
- Laptop (60 W, 3 h): 180 Wh
- Water pump (30 W, 0.5 h): 15 Wh
- Smartphone (10 W, 2 h): 20 Wh
- Total: approx. 745 Wh per day
If you want more convenience (e.g., an induction hob, coffee maker, or charging an e-bike), consumption will increase accordingly. The season and outside temperature also play a role. Heating or more lighting in winter increase demand. If you're interested in how to accurately determine your electricity consumption, what rules of thumb there are, and how different appliances affect your everyday life, then it's worth taking a look at Part 1 of our blog series. There you'll find all the basics and many helpful tips about power consumption in a camper.
The components – what do you really need?
A self-sufficient power system usually consists of these components:
- Supply battery (e.g. lithium, AGM): stores your power
- Solar system: provides you with energy during the day
- Charge controller (MPPT): regulates the current flow from the modules to the battery
- Inverter: converts 12 V DC to 230 V AC
- Charging booster & shore power connection: for additional charging on the go or at the pitch
- Fuses, cables, circuit breakers: for safety & protection
Which design and dimensions you need depends on how much you use, how long you want to go without recharging, and how much space and budget you have.
Solar panels & charging technology – The basis for efficient power generation
If you're using solar panels on your vehicle or in your off-grid system, choosing the right modules and charging technology is crucial. There are two main types of solar modules commonly used: monocrystalline and polycrystalline solar modules.
- Monocrystalline solar modules are characterized by high efficiency (up to 22%) and are particularly space-saving. They offer good performance even in low light and are the best choice for applications with limited space, such as vehicle roofs. These modules are durable and offer a modern, aesthetic design.
- Polycrystalline solar modules are more cost-effective, but have lower efficiency (typically 15–18%) and require more area to produce the same output. They are ideal for applications where space is not an issue and budget is a priority, such as stationary systems.
In addition to choosing the right module, the charge controller is also crucial. There are two main types:
- PWM (pulse-width modulation) charge controllers are cheaper and suitable for smaller systems with well-matched solar panels and battery voltages. They are easy to use but less efficient because they convert excess energy into heat.
- MPPT (Maximum Power Point Tracking) charge controllers offer significantly higher efficiency because they can optimize the solar panel voltage and convert excess energy into additional charging current. They are particularly advantageous in larger or more powerful systems and in changing light conditions.
To calculate your solar power output, you should determine your daily electricity consumption and compare it with the output of your solar panels. As a rule of thumb, 100 Wp solar panels in Central Europe deliver approximately 350 Wh per day. If your consumption is higher or the weather conditions are less favorable, you should plan for a larger buffer and adjust your solar power accordingly.
With the right combination of solar panels, charge controller, and optimized performance, you can ensure that you have a reliable and efficient power supply even when you're on the go.
Power conversion with the inverter – The right choice for your 230 V devices
If you want to power devices like your laptop, coffee maker, or other household appliances with 230 V while on the go, an inverter is essential. The inverter converts the direct current (DC) from your on-board battery into alternating current (AC)—so you can also use devices that would normally be plugged into a power outlet at home.
There are two main types of inverters, each with its own advantages and disadvantages:
- Pure sine wave inverters produce a smooth and clean sine wave, just like the power from your home wall outlet. This type of inverter is especially important if you want to power sensitive devices like laptops, coffee makers, or audio equipment, as these require a stable power supply to operate reliably and without damage.
- Modified sine wave inverters are cheaper, but produce a more irregular waveform. These are less suitable for devices with sensitive electronics, but may be sufficient for simple devices like fan heaters or power tools. If you want to be on the safe side and protect your devices long-term, you should choose a pure sine wave inverter.
The inverter's power output is also an important consideration. You should calculate the required power based on the devices you want to operate simultaneously. Also consider the starting currents, as some devices require more power when switched on than when in use.
Inverter installation is also crucial for the efficiency and safety of the system. Make sure the inverter is properly fused, that the cables are of the correct gauge, and that the inverter is installed in a well-ventilated location to avoid overheating. Furthermore, all connections should be kept as short as possible to minimize power loss.
Charging on the go – flexible and reliable even in bad weather
For true independence while traveling, it's important that you can power your onboard battery not only with solar energy but also with other charging options. Especially in cloudy weather, solar panels alone are often not enough to reliably charge the battery. Therefore, you should consider other options for charging your battery:
- Charging with an alternator and charging booster: When you're on the road, the alternator charges the vehicle battery by default. Using a charging booster also allows you to efficiently charge your onboard battery. The charging booster ensures that the alternator's power is optimally converted to achieve the correct charging voltage for your battery—especially important for modern lithium batteries. A charging booster allows you to charge quickly and efficiently, even on short journeys, and ensures a stable voltage, even with fluctuating alternator output.
- Shore power & mains power: At campsites or during extended downtimes, you can conveniently charge your battery using shore power. With a mains charger, you can not only charge the battery but also directly power 230 V devices. If you frequently rely on shore power, a permanently installed system with automatic switching between charging and inverter functions is a convenient solution.
- Mobile power stations: For maximum flexibility, mobile power stations offer a backup solution. These devices combine battery storage with an inverter, allowing you to operate your 230 V devices flexibly. They can be charged via solar, 12 V, or 230 V mains power and are an ideal solution for weekend trips, working on the go, or as an emergency power supply in bad weather.
- Alternator Charger: A newer solution is the EcoFlow Alternator Charger, which uses the alternator to charge a mobile power station while driving. This solution offers a fast and efficient way to charge the power station without relying on external power sources.
A combination of a charging booster, shore power, a power station, and, if necessary, an alternator charger ensures a reliable and flexible power supply on the go. This way, you'll always remain self-sufficient and well-prepared, whether in cloudy weather, during long downtimes, or on spontaneous adventures.
Security & Cabling – How to protect your system
Proper wiring is the backbone of your camper's power system, and safe installation is essential to avoid hazards such as short circuits, cable fires, or system failures.
- Cable cross-section: A frequently underestimated, yet crucial, factor. A cable cross-section that's too small leads to increased resistance, which can cause power losses and, in the worst case, overheating. When choosing the cross-section, you should consider both the current rating and the cable length. For high-current devices such as inverters, it's important to accurately calculate the cable cross-section to ensure a reliable power supply.
- Fuses: Every line directly connected to the battery should be protected by a fuse to prevent overheating or fire in the event of a fault. ANM or MIDI fuses are ideal for high-current circuits, while blade fuses are suitable for smaller loads. Circuit breakers offer a convenient way to quickly resolve overcurrent situations by tripping automatically and being reset at the push of a button.
- Disconnect switch: A disconnect switch disconnects the battery from the electrical circuit in an emergency, which is especially important for maintenance work or in the event of an accident. It should be installed in an easily accessible location to allow for quick response.
- Fire protection: To prevent fires, cables should be installed in a protected manner – for example, in cable ducts or corrugated pipes. Avoid chafing and ensure cables are not installed on hot surfaces or in damp areas. Regularly checking connections and avoiding overcharging by using intelligent charge controllers is also important to protect your battery from overload.
Safety comes first: To protect your technology and your vehicle from hazards, careful wiring with the right fuses, circuit breakers, and fire protection measures is essential. With proper planning and the right materials, you lay the foundation for a reliable and safe power supply on the road.
What suits your vehicle?
Not every system fits every vehicle. Therefore, you should consider the following when planning:
- Vehicle size and installation location: Where will the battery fit? Do the solar panels have enough space?
- Weight: Especially for vans and campervans with a 3.5 t limit, every kilo counts
- Accessibility & Maintenance: Can you easily reach fuses, switches, and connections?
- Integration into the existing system: Do you already have an electrical system, or are you planning everything from scratch?
Additional requirements apply to off-road vehicles or boats (vibration, splash water, temperature fluctuations).
Example system planning: Self-sufficient setup for 1,000 Wh consumption per day
Let's assume your daily power consumption is around 1,000 Wh and you want to be self-sufficient for three days without recharging. This results in the following example system:
- Battery capacity: 3 x 1,000 Wh = 3,000 Wh → for a 12 V system, approx. 250 Ah lithium battery (round up to 300 Ah with reserve)
- Solar power: 1,000 Wh ÷ 5 hours of sunshine = 200 W → with reserve: 300–350 Wp solar
- Inverter: at least 1,000–1,500 W (depending on device usage)
- MPPT charge controller suitable for solar power (e.g. 100/30)
- Dimension cable cross-section, fuses, circuit breakers as required
- Optional: Charging booster for alternator charging + shore power connection for emergencies
This configuration allows you to be completely self-sufficient when the sun is shining and to work, cool, charge, and cook during the day.
Don't feel like calculating it yourself? Here's our solar calculator:
https://solarkontor.de/Solarkontor-Solarrechner
How much does an autonomous power system cost?
Of course, the price depends on the chosen setup. Here's a rough overview:
- Entry-level setup (approx. €500–1,000): small battery (AGM), flexible solar bag, USB consumer
- Mid-range (€1,500–€2,500): Lithium battery, fixed solar system, MPPT, small inverter
- Comfort setup (from €3,000): large lithium bank, 300W+ solar panel, charging booster, 2000W+ inverter, professional cabling
With good planning and some DIY work, you can save a lot of money – but quality batteries, inverters, and security always pay off. It's also important to note that this is only a rough guideline. It's always better to calculate your exact needs and then select the right products!
DIY or specialist – which is better?
Do it Yourself:
- Costs less but requires technical understanding
- Perfect if you want to know your system exactly
- Caution: Mistakes can be expensive and dangerous (cable fire, device failure)
Installation by a specialist company:
- More expensive, but safe & professional
- Ideal for complex setups or high performance
- Often warranty on installation & components
Tip: If you are unsure, you can also plan a hybrid approach – purchasing and designing the system yourself, with professional installation.
Your individual system – well planned, reliably implemented
With the right knowledge and a little planning, you can put together a self-sufficient power system that's perfectly suited to you, your vehicle, and your travel plans. From the initial consumption list to the final backup, every step is important – and the more thoroughly you think it through, the more reliable your power supply will be on the road.
Whether DIY or with professional support: your “independent travel” project starts right here.
Thank you for reading our 7-part blog series to the end!
We hope that these articles have given you valuable insights, practical tips, and, above all, a taste for your own self-sufficient power system.
