What you need to know about Solar Inverters

What are inverters?

Inverter is the device that converts 12v DC power to 240v AC. They are available in different types and different sizes.

Why we need inverters?

In a standard caravan/RV/any other recreational vehicle, the power supply is normally one or a group of 12v batteries. The power supplied by 12v batteries would be 12v DC. The appliances that we plug in to the wall socket at home needs 240v AC as supplied by the grid. So if you would like to bring some of these appliances to your recreational vehicle, an inverter is needed to convert 12v DC from batteries to 240v AC to power them.

Here are some examples of 240v AC appliances that Australians like to use on their recreational vehicles.

TV, microwave, hair dryer, laptop, chargers for cameras, phones, tablets. Many of these appliances do have models available on the market that can accept 12v DC power source, they are called 12v TV, 12v microwave, 12v hair dryer and even12v coffee machines. But still many Australians prefer to use the ones that they use at home and it’s quite a large expense to purchase every appliance you need in 12v so an inverter is still considered as an essential device in recreational vehicle’s electrics.

What is the efficiency of inverters?

Inverter efficiency is usually in the range of 85 to 95%. Mostly in the 90%, so the efficiency is quite high. If one of your 240v appliances is drawing too much power, it’s usually because the 240v appliance itself consumes too much power, not because of energy loss in the inverter. Energy supply in recreational vehicle is scarce and most 240v appliances are not designed to be extremely energy efficient. The 12v versions, on the other side, are normally designed with low energy consumption as priority.

What types of inverters are there?

Two main types: modified sine wave and pure sine wave.

For detailed explanation, please visit: http://www.xantrex.com/documents/tech-
doctor/universal/tech1-universal.pdf

Summary: pure sine wave is better than modified sine wave as it replicates the characteristics of

the electricity supplied by grid and modified sine wave doesn’t. Complex electronics have to run off a pure sine wave inverter. If you are only powering light bulb or power tool you may get away with modified sine wave but for TV, laptop, a pure sine wave inverter is definitely needed.

What size inverter should I get?

This all depends on your actual usage. Simply calculate the minimum requirement by adding the power of the appliances that will be running at the same time together and add another 20% safety margin. Let’s say we have a 100w TV, a 100w laptop, a 20w charger and they will possibly be running at the same time. We will have (100+100+20) x (100+20) %= 264w. So a 264w inverter would be suitable (will end up with a 300w inverter of course). If you only run laptop, phone and camera chargers off it, the chance is 300w should be enough. But if you need to run hair dryer and microwave, please find out the power rating and calculate accordingly. Normally an inverter that is more than 1500w is needed.

Always buy inverters that are certified by Australian safety standard.

Only buy inverters that has this regulatory compliance mark displayed. This is the prove of compliance to Australian safety standard.

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