Inverters: Powering Your 12V Electrical System

When you're out in the bush or enjoying the ultimate camping experience, having access to power can make a huge difference. Whether you need to run a small kettle, a hair dryer, or even a coffee machine, inverters allow you to convert your 12V vehicle's power into usable 240V for standard household appliances. In this blog, we’ll break down what an inverter is, how it works, and how to size one appropriately for your camping and 4x4 accessories.

What is an Inverter?

An inverter is a device that converts the 12V direct current (DC) electricity stored in your vehicle’s battery into alternating current (AC), typically 240V, which is the standard voltage for most household appliances in Australia. This is essential for running any device that would normally plug into a standard wall outlet while you're off the grid.

In simpler terms: your car or 4x4 runs on 12V, but your kettle or laptop charger needs 240V. The inverter acts as the middleman, allowing you to use household devices while camping or on the road.

How Inverters Work in a 12V Electrical System

Inverters pull power from your vehicle’s 12V battery (or a secondary battery if you have a dual battery system) and boost that power up to 240V AC. They work through internal electronics that oscillate the power from DC to AC.

It’s important to pair an inverter with an appropriate battery and charging system (like solar panels or Redarc’s battery management systems) to avoid draining your battery too quickly. A fully charged battery will let you use your devices efficiently, but running power-hungry appliances for too long can cause battery depletion and leave you without enough juice to start your vehicle.

A Diagram depicting the voltage and amperage differences between the 12v power source and 240v accessory connected to the inverter

Notice due to the lower starting voltage at the battery, much more amperage is required from the 12v source to step it up to 240v while applying the appropriate amperage to power an accessory connected to the inverter.

This is why heavy cable is often used to run from the battery to the inverters input, and why most cigarette socket powered inverters are only capable of outputting approx. 150w at most.

diagram courtesy of:
Compactrv - Installing an Inverter

Sizing an Inverter for Your Needs

To ensure you get the right inverter, you need to consider both watts (the amount of power your appliances will draw) and inverter size (measured in watts). Inverters come in a range of sizes, but the most common sizes for 4WD and camping setups are 300W, 600W, 1000W, and 2000W.

What Appliances Are You Powering?

• Phone Charger: ~10-25W

• Laptop Charger: ~60-100W

• Small Kettle: ~800-1500W

• Hair Dryer: ~1200-1800W

• Coffee Machine: ~800-1500W

• LED Lighting: ~10-30W

• Portable Fridge: ~50-150W (depending on size and temperature settings)

For example, if you plan to charge your phone, run a laptop, and maybe make some coffee, you’ll want an inverter that supports at least 1500W. If you plan to power multiple appliances simultaneously, you’ll need to add up the wattage for everything you’ll use at once.

Common Types of Inverters

• Modified Sine Wave Inverters: These are cheaper but may not be as efficient for sensitive electronics like laptops or fridges. They can still run appliances like kettles, but you might experience some "buzzing" or reduced performance with certain devices.

• Pure Sine Wave Inverters: More expensive, but they produce a smoother and cleaner current that is better suited for running sensitive electronics. For reliable camping setups or 4WD accessories, a pure sine wave inverter is generally recommended, especially if you are running items like laptops, fridges, or TVs.

Note how a pure sine wave inverter more accurately replicates 240V A/C Current, while a modified sine wave inverter is more "rough." This is important to consider when choosing an inverter to power certain appliances. 

Why Sizing Matters

Choosing the right inverter is critical to avoid overloading your system. Using an inverter that is too small will cause it to overheat and shut down, while using one that is too large can drain your battery faster than necessary. Keep in mind that your vehicle's alternator or solar panel setup needs to be capable of recharging your battery while you’re using the inverter.

Conclusion

Inverters are an essential piece of kit for any 4WD enthusiast or camper who wants to bring some home comforts on their outdoor adventures. Whether you’re running a small fridge, brewing coffee, or just charging your devices, picking the right inverter will ensure that your 12V electrical system is up to the task. Don't forget to consider your power needs carefully and choose an inverter with enough wattage to handle your equipment.

Keen to learn more?

Check out the Redarc Australia blog to learn more about all things 12v Electrical, or read up on our blog post on setting up a 12v dual battery system