One of the most common mistakes new owners make when building their campervan's electrical system is using pliers for stripping and crimping cables. In doing this, they risk damaging the cable's conductor and creating an insecure connection.
Did you know some solar charge controllers require connection to the battery bank before the solar panels? Additionally, other charge controllers may only function if the solar panel's voltage exceeds the battery's voltage. But you will still find many owners of campervans and other motorhomes encountering problems with their solar charge controllers, as they didn't know about such special requirements.
In today's quick guide, we will highlight seventeen common mistakes people make when building a caravan 12V system or campervan electrical setup. These mistakes may seem minor, but most tend to become highly dangerous and costly to rectify.
Common Campervan and Caravan Electrical System Mistakes (and How to Fix Them)
Not Planning Your Campervan Electrical System
The first mistake many newbies make when building their campervan's electrical system is failing to plan properly or not planning at all. Many set up their system by randomly selecting components they believe are necessary. However, this often leads to mismatched components, undersized or oversized electrical circuits, and expensive reworks.
Solution: Before building your campervan's electrical system, ensure you thoroughly plan for it. Determine your goals for the final build and create a detailed diagram listing all required components, no matter how minor they seem.
Copying Someone Else's Caravan Wiring Setup
The second common mistake people make is attempting to replicate a friend's or someone else's campervan electrical system. However, everyone has unique needs and plans when embarking on a campervan journey. Copying someone else's setup risks creating a system that doesn't align with your specific needs or goals.
Solution: Here, we will return to thorough planning. Whether working with a new campervan or a pre-owned one with an existing system, you should outline your specific requirements first, then design your electrical setup around them.
Undersizing Your Battery Bank and Power Needs
It's so easy to run out of power for your campervan's devices and appliances while off-grid. It has actually happened to many caravanners and boondockers, but this is because they failed to properly size their camper's power supply to their needs. Randomly choosing a leisure battery bank or miscalculating energy demands often results in a power reserve that fails mid-task.
Solution: Calculate the total daily power usage of all devices. Use the resulting amp-hours or watt-hours to determine the ideal battery bank, factoring in your desired days of autonomy, preferred battery type, and its depth of discharge.
Choosing the Wrong Solar Panel Size
Many people often realise they need a solar panel when they have already started their caravanning or RVing journey. This is especially common among newbies who initially rely on a portable power station, believing it will be sufficient. Others may install a solar panel, but with insufficient power output for their needs.
Solution: Incorporate a solar panel (or multiple panels) into your campervan setup when installing the leisure battery bank. You also must properly size the solar panel by considering your total power usage, average sunlight hours in your location, and external inefficiencies.
Mismatching 12V and 24V Accessory Voltages
Not all DC accessories are designed for the same voltage requirements, yet many beginners assume they are. Connecting low-voltage devices to a high-voltage power source, even if both are in a DC configuration, can cause damage.
For example, plugging a 12V device into a 24V battery system can irreparably harm its circuitry. Similarly, connecting a high-voltage solar panel directly to a campervan battery bank can cause issues.
Solution: Always ensure your DC devices and appliances match your campervan's electrical system. If you have multiple battery systems (e.g., 12V and 24V), use a multimeter to measure the socket's output before plugging in any device.
Using the Wrong Cable Size for 12V Wiring
Another common mistake people make when building a campervan's electrical system is improper wire sizing. Many users randomly select cables without considering gauge, voltage drop, or operating temperature. But these three factors are very important when choosing an electrical cable.
Selecting a cable that is either too thin, with a high voltage drop, or a lower temperature rating than your conditions increases electrical resistance. Increased resistance in a cable reduces the power delivered to your device or appliance, potentially insufficient for initial startup. In extreme cases, high resistance can even cause the cable to overheat, melting the insulation and igniting surrounding materials.
Solution: Before purchasing wiring cables for your campervan, caravan, or motorhome's electrical wiring, ensure their ampacity matches your circuit's current. Use an online cable sizing calculator to confirm the cable length required for your circuit maintains a voltage drop of 3% or less.
Mounting Components Too Far from the Power Source
This issue is closely related to cable sizing mistakes, as mounting your battery bank far from your devices increases circuit length. A longer cable increases internal resistance, leading to a higher voltage drop. With a high voltage drop, the current and total power output decrease, potentially insufficient to start or operate your devices. If the cable's resistance is too high, the conductor may overheat, risking insulation meltdown and ignition of surrounding materials.
Similarly, placing solar panels and the MPPT charge controller far apart increases internal voltage drop, resulting in less power reaching the controller. If the charge controller is also distant from the battery bank, the power output decreases, leading to reduced charging amps.
Solution: Plan the placement of your solar panels, MPPT charge controller, and leisure battery bank to keep them as close together as possible. Then, determine the exact cable length needed, factoring in the current flow. If you wish to save costs on solar cables, consider adding an extra panel in series to increase voltage output, which reduces the required wire gauge.
Running Too Many Electrical Devices and Appliances
When customising your campervan, you can include all essential appliances needed for your off-grid trip. However, "essential" doesn't mean every appliance in your household. Attempting to replicate your household lifestyle in a camper results in too many electrical devices, leading to excessive power consumption.
Solution: When building and customising your campervan, include only the most essential devices and appliances - those you can't do without. You should prioritise low-voltage devices to minimise reliance on the power inverter. The inverter should be for power-hungry AC items like air conditioners, coffee makers, blenders, or hairdryers. We also recommend using these AC appliances during the day with solar energy whenever possible.
Using the Wrong Fuses and Circuit Breakers
Another common mistake people make when building their campervan's electrical system is using incorrect fuses or circuit breakers. Without proper circuit protection, your system is vulnerable to damage from overcurrent, overvoltage, or electrical faults like short circuits or arcing. In extreme cases, this can melt cable insulation and cause electrical fires.
Solution: Install a fuse or breaker on the positive (hot) power supply cable of your devices. Ensure the fuse or breaker is the correct type and size to provide maximum protection while avoiding nuisance tripping. To size a fuse or breaker properly, multiply the current flowing through the cable by a 1.25 safety margin.
Using the Wrong Tools for Electrical Wiring
Yet another frequent mistake among new campervan, caravan, and motorhome owners is using incorrect electrical wiring tools. Many novices are unaware of tools like wire strippers or crimpers, let alone own them. Instead, they often use regular pliers for everything, which is far from ideal.
For example, stripping cables with pliers can damage the conductor, reducing its current-carrying capacity. Similarly, crimping with pliers creates an insecure connection with the terminal, risking disconnection due to vibration, voltage drop, or overheating, which impacts overall performance.
Solution: Always use the appropriate electrical wiring tools for each task when building your campervan. Strip wire ends with a dedicated wire stripper, crimp cables with a crimper, and melt solder seal connectors with a dedicated heat gun (not an open flame like a candle).
Not Grounding Your Caravan Electrical System Properly
DC devices only require connecting the positive and negative terminals to the battery bank to function, right? Unsurprisingly, many new caravanners and boondockers believe this, as the battery bank has only two terminals. However, failing to properly ground the battery leaves circuits without a return path for excess current from electrical faults or external forces like lightning, risking device damage or electrical shocks.
Solution: Properly ground your DC devices by connecting their negative terminal to the battery bank's negative busbar, which should then connect to the chassis ground point. You should also ground AC devices (e.g., inverters) at a separate chassis point to prevent cross-currents with the DC system. This is why Australian regulations require a licensed electrician to install inverters in campervans.
Skipping Switches and Dimmers
Many newbies forget to include switches and dimmers when building their campervan's electrical system. But without dedicated switches, devices run constantly, even when not in use, draining the battery bank faster. This also leaves circuits without a way to isolate devices during maintenance.
Solution: Install a battery switch in the circuit leading to your main power distribution system (fuse panel or busbar). You should also include an isolation switch between your solar panels and the MPPT charge controller. Then, use dimmers for internal lights to reduce energy consumption and extend LED lifespan.
Buying Low-Quality Electrical Components
Your campervan is your home away from home, so don't cut corners when assembling it. The saying "cheap is expensive" holds true, as cheap, low-quality electrical components are often poorly made with inferior materials and lack proper quality control. They tend to fail prematurely, perform unreliably, and can be dangerous. For example, low-quality fuses may not blow, or circuit breakers may not trip, even when the circuit exceeds its rated power.
Solution: Always purchase high-quality electrical components from trusted brands and reputable dealers, such as Campervan Builders. While premium components may be costly, they save money in the long run and provide peace of mind.
Not Reading the Product's User Manual
Do you read the user manual for your new cell phone after unboxing? Most people don't, but building a campervan's electrical system is different - you must read the manuals for all components. Without doing so, you may install components incorrectly, missing critical details like recommended wire gauge, fusing, or installation diagrams. This can lead to system failures, device damage, or electrical fires.
Solution: Always read the user manual, taking note of key details, before installing any component in your campervan, caravan, or motorhome's electrical system. A perfect example of why this matters is the Victron MPPT solar charger, where the manual explicitly specifies that the panel's voltage "must exceed the battery voltage by 5 volts for the controller to start."
Ignoring the Product's Warranty Terms
Warranty terms for electrical components are as important as user manuals. Otherwise, incorrect installation can void your warranties in the event of damage. For instance, the manual of the Victron MPPT charge controller we mentioned above also states that the "maximum open circuit voltage of your solar panels cannot exceed 100V." Exceeding this limit and damaging the controller will void the warranty.
Solution: Always read the warranty terms for your electrical components, noting critical details, before integrating them into your campervan's system. You should also review warranty policies online before buying your desired item, as manufacturers and dealers rarely offer replacements or refunds for incorrect selections.
Not Future-Proofing the Electrical System
Another mistake new campervan owners make is designing their electrical system solely for current needs. While this isn't inherently wrong, it becomes problematic when you acquire new devices not accounted for in your initial power calculations, rendering your battery bank or solar panels insufficient.
Additionally, failing to consider future additions may require reorganising your system later, leading to time-consuming and costly reinstallations.
Solution: When planning your campervan's electrical system, account for potential future devices and appliances. Choose a larger battery or leave space for one, ensure wiring is adequately sized, and reserve roof space for additional solar panels. Moreover, you should select an inverter powerful enough to handle the operating and surge power of any future 230V appliances.
Poor Workmanship and Ignoring Standards
Many new owners of campervans and other adventure vehicles build their electrical systems without adhering to proper practices, standards, or regulations. This can lead to common issues like disorganised layouts with tangled or unlabelled wires, improper cable termination, incorrect sizing of components (e.g., cables, fuses, breakers), and exposed connections without heat-shrink sleeves.
Furthermore, some users mount components that are insecure or ignore ventilation requirements. Others disregard safety protocols, such as improper fusing, grounding, or mixing AC and DC wiring without separation.
All these are forms of poor workmanship that can compromise the performance, efficiency, reliability, and safety of the electrical system. It can also void warranties, fail inspections, or lead to legal issues in case of incidents.
Solution: When building your campervan's electrical system, strictly follow necessary practices and standards. Ensure all your connections are secure, wires properly insulated, electrical components correctly sized, and everything neatly organised. You should also verify that your setup complies with local and international electrical codes.
Final Thoughts
While there are others, these are the most common mistakes people make when building the electrical systems of their campervans, caravans, and motorhomes. Some are errors we made when starting out years ago, and we paid dearly for them. The mistakes often lead to costly repairs, performance inefficiencies, and serious safety hazards.
Luckily for you, we've outlined these mistakes with their consequences and how to avoid them. By steering clear of these pitfalls, building your camper's electrical system becomes easier and more rewarding, resulting in a safe, efficient, and reliable system for your off-grid adventures.
Frequently Asked Questions
What size fuse or breaker do I need for a campervan circuit?
To size a fuse or breaker properly, multiply the current flowing through the cable by a 1.25 safety margin. Install the fuse or breaker on the positive (hot) power supply cable of your devices, and ensure it is the correct type and size to provide maximum protection while avoiding nuisance tripping.
How much voltage drop is acceptable in caravan wiring?
Aim for a voltage drop of 3% or less. Use an online cable sizing calculator to confirm that the cable length required for your circuit stays within this limit, and make sure the cable's ampacity matches your circuit's current.
Do I need a licensed electrician to install an inverter in a campervan?
Yes. Australian regulations require a licensed electrician to install inverters in campervans. AC devices such as inverters should also be grounded at a separate chassis point to prevent cross-currents with the DC system.
Why won't my Victron MPPT solar charge controller start?
The Victron MPPT solar charger's manual specifies that the panel's voltage must exceed the battery voltage by 5 volts for the controller to start. Also note that the maximum open circuit voltage of your solar panels cannot exceed 100V - exceeding this limit and damaging the controller will void the warranty.
Ready to build a safe, reliable 12V setup? Browse quality batteries, solar panels, wiring, and circuit protection at Campervan Builders.
