1.1 – Battery Types, Voltage and Capacity
When you’re choosing the right leisure batteries for your campervan, you need to make three important decisions:
- Battery type
- Battery voltage
- Battery capacity
Below we go through each of these decisions in detail.
Important Note
This guide is created out of personal interest and aims to share general knowledge only. We cannot take responsibility for any installations or how the information is used. Always ensure you follow local laws and regulations, and if you’re unsure about anything, especially electrical work, consult a certified electrician or qualified professional.
1.2 – Battery Types, Voltage and Capacity
Although lead-acid batteries are initially cheaper for the same usable capacity, they have a shorter lifespan and are significantly heavier. In general, we recommend choosing lithium batteries for your campervan. Even though the upfront cost is higher, your electrical system will usually be cheaper over the long term.
Sealed Lead-Acid Batteries (SLA)
Advantages:
These batteries are sealed and maintenance-free, which means you don’t need to check or top up water levels. They are also relatively cost-effective.
Disadvantages:
They have a shorter lifespan than AGM and gel batteries. They are heavy and have lower efficiency when charging and discharging.
Typical use:
SLA batteries are often used in applications where budget is a key factor. They work well in stationary and less demanding use cases.
Lithium Batteries (LiFePO₄)
- Lightweight
- 100% usable depth of discharge
- Higher upfront cost
- Lifespan of over 10 years (more charge cycles)
Advantages:
LiFePO₄ batteries have high energy density, low weight and a long service life, often over 10 years. They offer 100% usable capacity and excellent cycle life. They also charge faster and are safer than many other lithium chemistries.
Disadvantages:
The higher purchase price can be off-putting, but this is often offset by the long lifespan and lower maintenance and replacement costs over time.
Typical use:
Perfect for leisure battery systems where weight, space and performance are important. Ideal for longer trips and use in varying climate conditions.
AGM (Absorbent Glass Mat) Batteries
- Essentially a lead-acid battery
- Around 400 cycles on average
- About three times more cycles than a traditional starter battery
- Electrolyte absorbed in a fibreglass mat
- AGM batteries tolerate vibration well
Advantages:
AGM batteries are sealed and maintenance-free, which means they don’t require topping up with electrolyte. They also tolerate deeper discharges better than traditional flooded lead-acid batteries.
Disadvantages:
They are heavier and have a shorter lifespan than lithium batteries. They also have lower efficiency when charging and discharging.
Typical use:
AGM batteries are popular because they are reliable and maintenance-free, especially in systems where space and budget are limited and you still want decent performance and robustness.
Gel Lead-Acid Batteries
- Basically a type of lead-acid battery
- Around 400 cycles on average
- Roughly 20% more cycles than a standard flooded lead-acid battery
- The electrolyte is not liquid but in gel form thanks to added silica
- More tolerant of vibration and tilting in a vehicle
Advantages:
These batteries use a gel-based electrolyte that prevents leaks. They have a long service life and are relatively maintenance-free.
Disadvantages:
Gel batteries are sensitive to overcharging and require specific chargers with the correct charging profile. They are also more expensive than standard flooded lead-acid batteries.
12 Volt Batteries
- Optimal for systems with less than 400 Ah capacity
- Many manufacturers to choose from
- No modifications required for standard 12V DC appliances
- Plenty of great online resources for installation
24 Volt Batteries
- May require converters for certain appliances
- Optimal for larger systems with more than 400 Ah capacity
- More compact and energy-dense solution
- Slightly more expensive and more complex to wire
1.4 – How Many Amp-Hours Do You Need in Your Campervan Electrical System?
To accurately determine how many amp-hours (Ah) you need in your campervan electrical system, we recommend checking out our full guide to sizing a campervan electrical system and creating a detailed energy budget.
However, as a basic guideline, here are some typical vanlife use cases with recommendations for each scenario. Note that all amp-hour figures below assume a 12V system. If you’re using a 24V system, divide each Ah figure by two.
The Weekend Warrior
Recommended capacity: 100–200 Ah
This vanlifer is usally a part time vanlifer that uses a simple selection of DC appliances, such as:
- A DC fridge
- Spot and LED lighting
- Maxxair fans
- USB chargers
Some setups include a 1,200 W inverter, but it’s not used for high-consumption tasks like cooking and water heating. Air conditioning is generally not practical with only 200 Ah of 12V lithium batteries. This type of system is most suitable for part-time vanlife.
If you’re on a strict budget, the fridge / cool box is usually the biggest energy consumer, so make sure to size your battery and recharging options primarily around that.
In our first build we used a 160 Ah battery and a powerful DC-DC charger, which was enough to run:
- Two phones
- Three LED light strips
- Two USB fans (2 × 5V)
- 32 L compressor cool box (48 W)
Because USB charging for phones and the GoPro took quite a long time, they were generally only charged in the evening / overnight, so make sure you bring a power bank each.
Recommended battery ideas:
Full-Time Vanlifers
Recommended capacity: around 400 Ah
The two most common battery voltages in off-grid systems for campervans and motorhomes are 12V and 24V.
Voltage can be explained as the potential difference or, in practical terms, the “pressure” or “speed” with which electrons move through a circuit. In general, the larger the total capacity of your battery bank, the higher the battery voltage that is suitable.
If you want to dive deeper into the differences between 12V and 24V setups, we have a full guide dedicated to this topic.
12 Volt Batteries – Summary
- Optimal for systems under 400 Ah total capacity
- Plenty of good installation resources online
- No modification needed for standard 12V DC appliances
- Many manufacturers and form factors available
24 Volt Batteries – Summary
- Optimal for larger systems over 400 Ah total capacity
- More compact and energy-dense solution
- Slightly more expensive and more complex to wire
- May require DC-DC converters for some appliances
Luxury Vanlife Without Compromise
Recommended capacity: 600 Ah or more
If you want all the comforts of a house connected to the grid, you’ll need at least 600 Ah of battery capacity (at 12V). This allows you to:
- Comfortably run air conditioning
- Cook with an induction hob
- Heat water
- Use a heater
Without constantly worrying about running out of power.
With such a large battery bank and high daily usage, it’s essential to ensure:
- fast charging via your alternator
- and plenty of solar power!
Some full-time vanlifers run this kind of capacity, especially those who spend winters at higher latitudes and need to manage with minimal solar input.
Suggested battery options for this level of capacity:
- 3x 280Ah GC3 LiFePO4 Deep Cycle Batteries (12V)
- 330Ah Victron LiFePO4 Battery (12V)
- 3x200Ah RVPZER LiFePO4 Batteries (12V)
- 200Ah Victron LiFePO4 Batteri (24V)
1.5 – Different Ways to Charge Campervan Batteries
Running out of power on the road is every vanlifer’s nightmare. To minimise the risk, we recommend diversifying your charging options.
If you live in your van full-time, we strongly suggest having all three of the following:
- Solar power
- Alternator (DC-DC) charging
- Shore power (hook-up)
Solar Power – Installing Solar Panels
The holy grail of off-grid vanlife! A full energy budget will help you determine how much solar you need to keep your campervan batteries topped up. But we can already say this: it usually pays to maximise the size of your solar array, to save work later and give yourself more flexibility.
For solar systems above 300 W, consider switching from many small 100 W panels to larger 175 W, 200 W or bigger panels. On our campervan, Rover, we use two 370 W residential-style solar panels. By using larger panels you:
- simplify cable runs
- make mounting easier
- and can often fit more total wattage on the roof
Trust us, you’ll thank us later! Just keep in mind that it can sometimes be harder to source a few large panels. The downside of maximising solar is losing roof space, so plan your roof layout carefully.
What’s the Difference Between Wiring Solar Panels in Series vs Parallel?
When solar panels are wired in series, the positive terminal of one panel is connected to the negative terminal of the next.
Benefits of series-wired solar panels:
- Higher voltage with the same current (amps), which can allow you to use a cheaper MPPT charge controller
- You can sometimes use cable with a smaller cross-section
- In many cases it gives better performance over long cable runs
Benefits of parallel-wired solar panels:
Higher current: The total current is the sum of the current from each panel, which can be useful for applications that require higher power at lower voltage.
Fault tolerance and redundancy: If one panel is shaded, dirty or fails, the performance of the entire system is not reduced as dramatically. The other panels continue to produce power.
DC-DC Charging via the Vehicle Alternator
You can charge your campervan batteries while driving by using a DC-DC charger. We see this as “free” power, because you can plan your driving to ensure your batteries are full when solar on its own isn’t enough.
We always recommend maximising your total charging capability to cope with short winter days. Use the guidance below to decide whether you need one or two Victron Orion 30 A DC-DC chargers.
For example, the Victron Energy Orion-Tr Smart 12/12, 18 A is designed for 12V to 12V and can deliver 18 A. So think carefully before you buy a DC-DC charger that is too small, especially if you’re running without solar panels.
One DC-DC Charger (Popular Solution)
This is suitable if:
- Your vehicle alternator is 160 A or less
- You’re a “weekend warrior” with a smaller electrical system
- You have 200 Ah or less of lithium batteries to charge
Shore Power via an Inverter-Charger
You can use an inverter that also charges your batteries from shore power. For this you need a combined inverter-charger. Here are some of our favourite models in different sizes:
Victron Multiplus II 12V, 3000 W, 120 V – 50 A Inverter-Charger
- Slim design and weighs about 22 kg
- Dual 50 A AC outputs
- Charges a 12V battery bank up to 1440 W (120 A)
- This is what we use in our van!
Victron Multiplus C 12V, 2000 W, 80–50 A Inverter-Charger
- Compact and lightweight at only around 11 kg
- Single AC output
- Charges a 12V battery bank up to 960 W (80 A)
2.1 – What’s the Difference Between AC and DC?
In simple terms, there are two ways to use your conversion van’s leisure batteries:
- 12V (or 24V) direct current (DC)
- Mains voltage alternating current (AC) for example 120 V in North America,or around 230 V in many European countries
Always check the mains voltage standard in your country before you start your build!
For a more complete overview of AC and DC systems you can read our dedicated guide. In short, it is very important that you:
- Use AC-rated fuses in AC systems, and
- DC-rated fuses in DC systems.
AC fuses can generally handle higher voltages and are more resistant to electrical arcing when the fuse operates compared with DC fuses.
Here is a quick summary of DC and AC power in a campervan.
2.2 – DC Appliances in a Campervan
DC power is the heart of your entire off-grid campervan electrical system. It covers almost everything that is permanently installed in your van. DC power is more efficient than converting energy to AC and then using it, so as many of your appliances as possible should run directly on DC.
We believe your campervan should be fully self-sufficient on DC power alone (we’re looking at you, little AC mini fridges!), so that you don’t need to keep your inverter on 24/7. An inverter’s idle consumption is surprisingly high (typically 10–30 W depending on the model), and turning it off as much as possible will save a lot of energy.
Here’s a list of DC appliances we have in our own van, plus some others that many vanlifers use. All are connected via a DC distribution panel.
Typical DC loads:
- Heater for fresh/grey water tanks
- Maxxair roof fans
- Dometic compressor cool box / fridge (e.g. CK 40D Hybrid 12 V, 38 L)
- LED puck lights
- LED strip lights, IP65 water-resistant
- Water pump
- Electric ball valve
- Three-stage water filter with carbon filter
- Portable toilet / campervan toilet
- LED reading lights
- Campervan heater
- USB charging outlets
AC Appliances in Your Campervan
While your campervan can be run entirely on DC power, using AC appliances opens up a whole new world of comfort and convenience, making vanlife feel much more like being at home.
AC power is everything you plug into a standard mains socket. Here are some favourites for the road:
- Laptop charger
- Electric kettle
- Portable hob / camping stove (when electric)
- Hand blender / stick mixer
- External monitor
What’s the Difference Between AC and DC Fuses and Circuit Breakers?
For a full summary of AC and DC electrics you can read our separate guide. In short, it is extremely important that you:
- Use AC fuses in AC systems
- DC fuses in DC systems
AC fuses can usually handle higher voltages and are more resistant to electrical arcing when the fuse operates compared with DC fuses.
Fuse Performance: Terminology and Ratings
Rated voltage:
This is the maximum voltage the fuse is designed to handle. Typical ratings include 32, 60, 125, 300, 500, 600 and 750 volts.
Minimum fusing current:
This is the current at which the fuse element reaches a temperature where it melts. The minimum fusing current is significantly higher (about 1.25 to 2 times) than the fuse’s rated current.
Rated current:
This is the current printed on the fuse body. It is lower than the minimum fusing current. In other words, fuses can usually carry 1.25 to 2 times their rated current for a limited time before blowing.
Pre-arcing / melting time:
This is the time it takes for a fuse to blow after the current has exceeded the minimum fusing current. There are ultra-fast, fast and slow-blow fuses. Fast-acting fuses are generally used to protect sensitive electronics.
2.3 – The Ultimate Guide to 12V Fuse Boxes for Campervans
Knowing how to fuse your campervan’s electrical system correctly is crucial. Proper fusing protects your system from short circuits, overloads and fire.
In this guide you will learn:
- the differences between fuses and circuit breakers in AC and DC systems
- how to size your fuses
- how to choose the right fuse type
- and how to wire a fuse box or distribution panel in a campervan
By the end you’ll be ready to dive into your campervan electrical system with confidence.
Good to Know About Circuit Breakers
There are two main categories of circuit breakers: thermal and magnetic.
- Thermal breakers trip when a certain temperature is exceeded.
- Magnetic breakers trip when the current exceeds a set value.
Magnetic breakers are generally preferred for van conversions.
Key terms:
- Rated voltage: The maximum voltage the breaker is designed to handle.
- Rated current: The current printed on the breaker body.
- Trip current: The current at which the breaker actually trips. This is normally around 130% of the rated current.
- Trip time: The time it takes for the breaker to trip after the current has exceeded the trip current.
2.4 – How to Choose the Right Fuse for wiringing
Step 1: Calculate the Correct Cable Size
Before choosing a fuse, it’s important to size the cable you’re protecting correctly. Learn how to size cables properly in our cable-sizing guide, or use our handy cable size calculator.
Step 2: Choose a DC Fuse
The basic rule of thumb for fuse sizing is:
“Always choose a fuse size that protects the cable according to its rating.”
DIY campervan builders should generally size their cables larger than they think they need. Most of us aren’t chasing maximum cost/weight efficiency – we’re chasing maximum safety.
To calculate the fuse value, we should work out the total current draw of the appliance(s) the cable feeds and then add a 25% buffer.
Example:
Let’s say we have eight 12V puck lights at 3 W each.
- Current per light: 3 W ÷ 12 V = 0.25 A
- Eight lights: 0.25 A × 8 = 2 A total
We give ourselves a 25% buffer:
- 2 A × 1.25 = 2.5 A
So we choose a 2.5 A fuse (or the nearest suitable value) for this circuit, as long as it is within the cable’s rating.
Once we know the fuse size, we can move on and choose the right fuse type. Let’s look at some of the most common fuses.
2.6 – What’s the Difference Between the Various Fuse Types?
MIDI, MEGA, ANL and Class-T Fuses [30 A – 400 A]
These fuses are all designed for high-current applications. Most of them are inline fuses, which means they are installed directly in the cable.
In van conversions we use ANL and MEGA fuses to protect equipment such as inverters and battery chargers.
- Class-T fuses: 110 A – 400 A
- MIDI fuses: 30 A – 200 A
- MEGA fuses: 100 A – 300 A
- ANL fuses: 35 A – 400 A
AGC and MDL Fuses [0.25 A – 30 A]
AGC and MDL fuses are slow-blow glass-tube fuses with brass end caps. The glass tube provides a visible indication when the fuse has blown. They are inexpensive fuses used for small appliances.
Blade Fuses [1 A – 80 A]
Blade fuses are the most common fuses found in vehicles. They are cheap, colour-coded and easy to replace. When a blade fuse blows, it’s visible inside the plastic housing.
Van converters tend to use blade fuses in their 12V campervan fuse boxes. They are used for small to medium-sized loads.
- ATO fuses: designed for 1 A to 30 A
- MAXI fuses: designed for 30 A to 80 A
Terminal (MRBF) Fuses [30 A – 300 A]
Terminal fuses are used almost exclusively to protect leisure batteries. They are rated for high current and conveniently bolt directly onto the battery terminals.
MIDI, MEGA, ANL och Klass T Säkringar [30A – 400A]:
Dessa säkringar är alla designade för att ta en stor ström. De flesta av dem är inline-säkringar, vilket innebär att de installeras på kabeln. I van-konverteringar använder vi ANL och MEGA säkringar för att säkra saker som invertrar och batteriladdare. MIDI-säkringar är designade för att hantera 30A till 200A, MEGA-säkringar är designade för att hantera 100A till 300A, ANL-säkringar är designade för att hantera 35A till 400A, och Klass T-säkringar är designade för att hantera 110A till 400A.
MIDI, MEGA, ANL and Class-T Fuses [30 A – 400 A] (Recap)
As mentioned above, these fuses are designed for high currents. Most are inline fuses mounted in dedicated holders on the cable.
In van conversions ANL and MEGA fuses are commonly used to protect inverters and battery chargers:
- Class-T: 110 A – 400 A
- MIDI: 30 A – 200 A
- MEGA: 100 A – 300 A
- ANL: 35 A – 400 A
2.7 – Choosing the Right Fuse Holder
After you’ve chosen the correct fuse, you’ll need a fuse holder for it. The choice depends on the purpose of the fuse and where you plan to mount it. When the current flowing through a circuit exceeds the fuse’s rating ( for example a ANL 35A), the metal inside the fuse melts, or “blows,” and breaks the circuit. By interrupting the flow of electricity in a fault condition, it protects the vehicle or setup from electrical fires.
This stops the flow of electricity, protecting the wiring and devices on that circuit.
There are treemain types of fuse holders:
- Inline fuse holders: Compact holders that take a single, usually low- to medium-current fuse, installed directly in the cable.
- Block (or panel) fuse holders: Mounted to a solid surface and can hold a single fuse or multiple fuses (for example, a 6- or 12-way blade fuse block).
- Classic 12v Fuse box: A fuse box divides the electrical system into smaller, fused circuits. This isolates faults, so if one circuit fails, the others remain operational. It protects the vehicle or setup from electrical fires by interrupting the flow of electricity.
Popular Complete Solar Panel Kits
2.8 – Fuse Box and Switch Panel for a Campervan
Most van converters install a simple 12V fuse box in their campervans. This becomes the central hub from which we protect our smaller 12V DC appliances. These might include:
- Lighting
- A roof vent / fan
- Water pump
- A diesel or LPG heater
- Possibly the fridge
12V fuse boxes usually take ATC blade fuses. Buying an assorted kit of blade fuses is a very good idea – it’s important to have a range of spares on hand when you need them.
If we use solar power in our campervan, we usually connect the fuse box directly to the solar charge controller, which allows us to monitor parts of the DC system nicely.
If you don’t have solar in your campervan, connect the fuse box directly to the main bus bars that link to your leisure batteries (with appropriate main fusing near the battery).
We usually install a switch panel between the campervan fuse box and the 12V appliances. This allows us to turn each circuit on and off individually.
Blade Fuse Sizes
When choosing blade fuses for your 12V fuse box, you must ensure they are correctly sized. There are several types of blade fuses, each designed for specific applications and available in different current ratings.
The most common blade fuse sizes include:
- Mini blade fuses: Usually available from 2 A to 30 A.
- Standard blade fuses: The most widespread and versatile type, typically from 2 A to 40 A.
- Maxi blade fuses: Larger and designed for heavy-duty applications, usually from 20 A to 100 A.
Blade fuses are often colour-coded for easy identification.