Camper Inverter Installation: A Step-By-Step Guide

If you're looking to hook up an inverter in your camper, you'll need to know the basics of how they work and what to consider when choosing one. RV inverters are devices that convert the direct current (DC) power from your camper's battery into alternating current (AC) power, which is what most appliances run on. This allows you to power appliances when you're not connected to shore power or using a generator. When choosing an inverter, you'll need to consider factors such as wattage and power rating, input and output voltage, and efficiency. You'll also need to decide how you want to install it, whether directly to the battery, to the AC distribution box, or via a cigarette lighter. Once you've chosen your inverter and installation method, be sure to carefully follow the manufacturer's instructions for a safe and successful installation.

Choosing the right inverter

Understanding Inverter Types:

There are three main types of inverters: Pure Sine Wave, Modified Sine Wave, and Square Wave. The Pure Sine Wave inverter is the most suitable for sensitive electronic equipment, such as laptops, smartphones, modern TVs, medical devices like CPAP machines, refrigerators, microwaves, and high-powered appliances with motors. It provides a stable power source and protects internal components from potential damage. Modified Sine Wave inverters are suitable for non-sensitive appliances but may not work with all electronic devices. Square Wave inverters have poor compatibility and are the least suitable option.

Power Requirements and Wattage:

To determine the size of the inverter you need, calculate the total wattage of the appliances you plan to use simultaneously. Consider both the continuous power rating, for steady appliance operation, and the surge power rating, for starting up appliances. For example, if you want to run a laptop (100W) and a microwave (900W) at the same time, you'll need an inverter with a continuous power rating of at least 1000W. Pay attention to appliances with high surge power demands, such as microwaves or refrigerators, and ensure the inverter's surge rating can accommodate their initial power spikes.

Battery Compatibility:

Make sure the inverter matches your battery's voltage, typically 12V or 24V. If you plan to run larger appliances or have higher power consumption needs, consider upgrading to a higher-capacity inverter and battery system, such as a 24V or even 48V setup. The inverter's power consumption and the battery's capacity should be compatible to ensure efficient power usage.

Efficiency and Standby Consumption:

Look for an inverter with a high efficiency rating, ideally between 85-95%, to minimize energy loss during power conversion. Additionally, choose an inverter with low standby consumption to prevent unnecessary battery drain when it is turned on but not actively powering any devices. This will help extend your battery life and reduce energy wastage.

Size, Safety, and Installation:

Select an inverter that fits the available space in your camper and has built-in safety features like overload protection, short circuit protection, and over-temperature shutdown. It’s important to install the inverter with proper ventilation to avoid overheating and to extend its lifespan. Refer to the manufacturer's guidelines for recommended ventilation requirements and installation instructions.

When choosing an inverter, it's always a good idea to opt for a slightly higher power rating than you think you'll need to accommodate any unforeseen power surges or additional appliances you may want to use in the future.

Preparing the camper for installation

Before you start the installation, it's important to prepare your camper and ensure you have the right equipment. Here are some key steps to follow:

• Buy a compatible inverter: Not all inverters are suitable for your RV's electrical setup. Ensure the inverter has the correct input and output voltage, a pure sine wave version for sensitive electronics, a good efficiency rating, and a low idle consumption rate.
• Read the manufacturer's manual: The manual will provide essential safety information, installation instructions, and operating guidelines. Read it thoroughly before starting the installation.
• Choose an installation location: Select a dry, well-ventilated area away from water sources and flammable objects. Keep the inverter close to the battery bank to minimise cable voltage losses and ensure proper grounding.
• Gather the necessary tools and materials: You'll need a multimeter, wire strippers, heat shrink and a heat gun, a terminal crimping tool, a drill, screwdrivers, cable ties or clips, fuses, and correctly sized wires and connectors.
• Disconnect power sources: Before beginning the installation, disconnect the battery bank power supply, shore power, and the generator. This will ensure your safety and prevent any damage to the electrical system.
• Understand your electrical system: Familiarise yourself with your camper's electrical system, including voltage requirements, fuse sizes, and grounding/earthing requirements. This knowledge will be crucial during the installation process.
• Consider hiring an electrician: If you're unsure about any aspect of the installation, don't hesitate to consult a qualified electrician. They can provide expert guidance and ensure a safe and proper installation.

Connecting the inverter to the battery

Step 1: Choose the Right Location

It is essential to select an appropriate location to install the inverter in your camper. Ensure that it is a dry area, well-ventilated, and away from any water sources or flammable objects. Try to install the inverter as close to the battery bank as possible to minimise cable voltage losses. This will help you avoid using larger wire sizes, which can be more costly and space-consuming. Additionally, keeping the inverter close to the battery will help prevent excessive voltage drop. However, if you are using flooded lead-acid batteries, do not install the inverter in the same compartment to avoid the potential fire hazard.

Step 2: Secure the Inverter

Once you have chosen the ideal location, it's time to secure the inverter in its place. Most inverters come with manufacturer-drilled holes that you can use for mounting. Follow the manufacturer's instructions carefully when securing the inverter to prevent any damage or hazards.

Step 3: Ground the Inverter

Grounding the inverter is a critical step for your safety. Inverters convert DC current to AC, and AC current can be harmful or even fatal. Refer to the manufacturer's instructions to correctly ground the inverter. They will specify the correct fuse size and provide details on the grounding procedure.

Step 4: Connect the Inverter to the Battery

Now, you can begin wiring the inverter to the battery. The exact terminals for connection may vary depending on the inverter model, so carefully follow the manufacturer's instructions. You will need to connect the positive and negative cables from the inverter to the corresponding terminals on the battery. Ensure that the connections are secure and tight.

Step 5: Confirm Connections and Test

After making all the connections, confirm that all connections are secure and tight. Switch on the inverter without connecting any AC appliances. Use a multimeter to check if you have a 12V DC supply to the inverter. If the multimeter reading is satisfactory, you can proceed to connect an AC appliance to test if it is powered as expected.

Additional Tips:

• Always use the correct size wires and fuses as specified by the manufacturer.
• When in doubt, consult a qualified electrician.
• If you plan to use an extension cord with your inverter, ensure it has a higher current rating than the combined current of the appliances you will use simultaneously.
• If you intend to run high-power devices like microwaves, consider investing in a sine wave inverter, which is more expensive but allows for most appliance types.

Wiring the inverter to the AC distribution box

• Choose a suitable location for your inverter. It should be close to the battery to minimise cable voltage losses, but also away from fluids, flammable objects, and with adequate airflow to keep it cool.
• Secure the inverter to its chosen location, using manufacturer-drilled holes and following the instructions provided.
• Wire the inverter to the battery, following the specific instructions for your model.
• Ground the inverter according to the manufacturer's instructions. This is a critical step for your safety as inverters convert DC to AC, which can be harmful or even fatal.
• Install a transfer switch. This is essential to isolate the inverter from shore power and prevent damage.
• Connect the inverter to the AC distribution box, ensuring the inverter and converter are on separate parts of the board.
• Confirm that all connections are secure and tight.
• Test the inverter by switching it on and connecting an AC appliance to ensure it is powered as expected.

Please note that this is a complex process, and it is recommended to refer to the manufacturer's instructions and seek professional assistance if needed.

Testing the inverter

Testing your RV inverter is a complex procedure that must be done in the correct sequence. Here is a step-by-step guide to testing your RV inverter:

Step 1: Disconnect from shore power and other power sources

Turn off the shore power and other power sources such as a generator or RV. This is important to ensure that you are only testing the inverter and not any other power sources.

Step 2: Turn on appliances powered by the inverter one at a time

Turn on each appliance that is powered by the inverter individually. This could include items such as the refrigerator, microwave, or television. If an appliance is working, turn it off before testing another appliance. This will help you identify which appliances are powered by the inverter and ensure that they are functioning correctly.

Step 3: Test outlets powered by the inverter

After testing individual appliances, plug a small accessory into any outlets powered by the inverter to test them. Most RV inverters only operate one or two circuits, so it is important to test multiple outlets to identify which ones are powered by the inverter. Your owner's manual will specify which outlets should be powered by the inverter.

Step 4: Check for adequate DC power supply

Most RV power inverters have a status light that indicates whether the inverter is on or off. If the status light is off, it could be due to the inverter being switched off or a lack of DC voltage connected to the inverter. Ensure that the inverter is switched on and connected to a battery with the correct voltage. A healthy RV battery should have a voltage above 12.5 volts DC.

Step 5: Test incoming AC voltage

Some RV inverters have a dropout setting if the incoming AC voltage is lower than the programmed threshold (typically around 80 volts AC). Set your voltmeter to the volts AC setting and connect the probes to the AC neutral and lead wires. Ensure that the voltage is above the inverter's AC dropout level. If it is below the minimum threshold, there may be an issue with your shore power source.

Step 6: Check circuit breakers and fuses

If you are experiencing issues with specific appliances or devices, locate your RV's electrical panel and identify the breaker that serves the malfunctioning device. Reset the breaker by turning it off and then back on again. If the breaker trips repeatedly, there may be an issue with the breaker itself or the appliance may be drawing too much power. Consult an RV service technician for further advice.

Step 7: Examine the cooling fan

If there are no issues with the battery, incoming AC shore power source, circuit breakers, or fuses, the problem may lie with the inverter's cooling fan. Listen for the fan to cycle on and off periodically when the inverter is in use. If the fan is not functioning properly, it could cause heat buildup and damage critical inverter components. Visually inspect the inverter for any signs of melting or deformation. Ensure there is adequate airflow around the inverter to prevent overheating.

Frequently asked questions