Inverters - Comprehensive Guide | iTechworld

Inverters - Comprehensive Guide

240v - 12v Inverters

Everyone uses some kind of electronic gadget while in their motor-home, caravan or car. You might listen to your MP3 player, use a GPS or the kids might play a portable video game. A lot of these types of electronic devices can be recharged or powered by plugging them into the cigarette lighter in your vehicle.

But what if you want to use something a little more elaborate while you're on the open road? Maybe you want to make toast, boil a kettle, or perhaps even write an article on your laptop computer. These devices plug into regular wall outlets, not cigarette lighters. Making sure your electronic gear gets the juice it needs while on the road isn't a simple matter of finding the right adapter. You need a power inverter.

­Power inverters convert direct current (DC), the power that comes from a car battery, into alternating current (AC), the kind of power supplied to your home and the power larger electronics need to function. What kind of power inverter is the right one for the job? How do you install one? And how exactly does an inverter change the current from one form to another? In this blog, we'll explore all the positives and negatives of DC to AC power inverters.

 

Why Do I Need To Convert from DC to AC?

Most cars and motor homes derive their power from a 12-volt battery. The battery provides direct current. This means that the current flows continuously from the negative terminal of the battery, through the completed circuit and back to the positive terminal of the battery. The flow is in one direction only, hence the name direct current. The ability to provide direct current power is inherent to the nature of batteries.

Direct current is very useful, but batteries can generally only provide relatively low-voltage DC power. Many devices need more power to function properly than DC can provide. They're designed to run on the 240-volt AC power supplied to homes in Australia. Alternating current or AC, constantly changes polarity, sending current one way through the circuit, then reversing and sending it the other way. It does this very quickly. AC power works well at high voltages, and can be "stepped up" in voltage by a transformer more easily than direct current can.

An inverter increases the DC voltage, and then changes it to alternating current before sending it out to power a device. These devices were initially designed to do the opposite -- to convert alternating current into direct current. Since these converters could basically be run in reverse to accomplish the opposite effect, they were called inverters.

 

Making Direct Current Alternate

The earliest AC power inverters were electro-mechanical devices. Direct current would flow down one end of a circuit with an electromagnet. As soon as the current hit the magnet, the magnet would activate. This would pull a wire attached to a spring arm, forcing the wire to contact the circuit. This would change the flow of the current to the other side of the circuit, cutting power from the electromagnet. As soon as the magnet released, the spring would snap the wire back, allowing the current to flow on the other side of the circuit, once again activating the magnet. These old inverters were known for making a buzzing sound.

Modern inverters use oscillator circuits to accomplish the same process. They're made with transistors or semiconductors, so there's no longer the need for a spring arm flipping back and forth to alternate the current.

It's not quite as simple as that, however. Alternating current forms a sine wave. The output of an inverter is a very square wave, not like the smooth, round wave of a pure sine. Some devices are inherently sensitive to the signal produced by an AC wave. Typically, these are devices that receive or broadcast some kind of signal, such as audio or video equipment, navigation devices or sensitive scientific equipment. You can see or hear the square waveform on a television as lines on the screen or a steady buzz or hum.

Cleaning up the sine wave requires a series of filters, inductors and capacitors. Inexpensive inverters have little or no filtering. The alternating current they produce has a very square wave, which is fine if you just want to make coffee or run something with a simple electric motor. If you need a smoother sine wave, you'll need an inverter with better filtering. Of course, better filtering also costs a little more.

 

Watts, Peaks and Surges

The first step in selecting an inverter is to match the inverter to the voltage of the battery you'll be using for power. In the majority of cases, you'll be using a 12-volt battery, so you would want to select a 12-volt inverter.

The next step is to determine which devices you plan to power with the inverter. Look for a label somewhere on each device that tells you the wattage it requires to operate. The wattage rating of your inverter must exceed the total wattage of all the devices you plan to run simultaneously. For instance, if you wanted to run a 600-watt blender and a 600-watt coffee maker at the same time, you'd need an inverter capable of a 1,200-watt output. However, if you knew you would never be making coffee and fruit smoothies at the exact same time, you'd only need a 600-watt inverter.

Devices that have electric motors, draw a higher wattage than their normal operating wattage rating when they first start up. This is known as peak or surge, and this information should also be listed on the device's label. All iTechworld inverters have a peak rating, so make sure the inverter's peak rating is higher than the peak wattage of the device you intend to power.

The final specification to look for is the wave output of the inverter. If you'll be powering any of the equipment that is sensitive to square waves, look for an inverter with a "pure sine wave" output. Modified sine means that the current is run through some filtering, so it isn't a square wave, but it isn't totally smooth either.

 

Inverter Installation

Inverters are very easy to install. Most of them are "plug and play" devices. All iTechworld inverters come with heavy duty cabling that goes straight on to your battery termianl. The inverter itself can be mounted anywhere, although it should be in a place with good air flow. All iTechworld inverters are state of the art and use cooling fans and heat dissipation fins to prevent overheating. Inverters can be used as a portable device or can be mounted using mounting holes, so they can be bolted to any surface. Obviously, with a permanent installation, you'll probably want to bolt your inverter in place, but this isn't absolutely necessary. It's possible to simply place the inverter in a secure, stable position, clip the leads to the battery and plug in.

Just what does an inverter look like, anyway? Well, the smallest inverters can fit in your pocket, while higher-wattage models are roughly the size and weight of a large dictionary. As a general rule: The higher the wattage, the larger and heavier the inverter. At the top of the inverter wattage scale, our 2000 Watt weighs 6kg.

All iTechworld inverters have amazing features that make them a must have and really easy to use.

Australian-standard power points
Low voltage input protection
Short-circuit protection
Overload, over-voltage protection 
12-month warranty
Socket Type: Australian Standard
Output Voltage and Frequency: 240V AC
Input Voltage:  12V DC
Overload Protection
Over Voltage Protection
Output Short Protection

A common myth with inverters is that they chew up a lot of amps from your battery. This may have been the case with older inverters, however all iTechworld inverters are equipped with the most up to date technology available. Our largest inverter (2000/4000 Watt Pure Sine Wave Inverter) only draws between 0.8 Amps and 1.8 Amps with no load, this is the equivalent power draw to some LED lighting. The power draw with a load connected is dependent on how many Watts the device is.

So how much is all of this going to cost, you ask? Not as much as you may think.... 

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Article author

Ian

[email protected]

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