What is the best type of inverter to use?

3 March 2023

MEAN WELL produces a range of inverters that are suitable for use in small scale solar and battery systems, such as those typically found on caravans and boats.

There are 2 types of inverter that are available; True Sine Wave Inverters and Modified Sine Wave Inverters. So, which one should you use?

We take a look at both types, explaining the different ways in which they function and the applications they are best suited to.

Of course the first question you have is “What is the difference between a True Sine Wave inverter and a Modified Sine Wave inverter?”

Both types of inverter take direct current (DC) from a battery, solar panel or other generating source and convert it into 240V alternating current (AC). It is at the AC output stage that the types of inverter differ.

Alternating current means that the current is alternating its direction of travel repeatedly at a very fast rate. This rate is measured in frequency (Hz). In Australia the 240VAC power supply is delivered at 50Hz (50 cycles per second).

The AC mains power delivered to your home or business alternates smoothly with a sinusoidal curve that has a rounded peak and a clean ‘zero cross’ to a rounded valley (Fig.1).  This is what we know as a true sine wave and the output of a true sine wave inverter looks similar.

True Sine Wave

Fig 1

Where a modified sine wave inverter differs is that it produces instantaneous peak voltage for a few milliseconds, drops down to zero for a few milliseconds, then returns to the valley. (Fig 2.)

Modified Sine Wave

Fig 2

So what are the pros and cons of these two inverter types?

Modified Sine Wave Inverter

Modified Sine Wave Inverter
Modified Sine Wave Inverter


Modified sine wave inverters are generally cheaper than a true sine wave inverter and perform well in many applications.

They are best suited to powering electrical equipment that does not have any sensitive electronic circuitry. For example; a simple induction load like a motor, or a resistive load like a heating element.

So if you want to run appliance such as fans, toasters, or vacuum cleaners a modified sine wave inverter is a great low cost solution.

True Sine Wave Inverter

MEAN WELL True Sine Wave Inverter
MEAN WELL True Sine Wave Inverter


A true sine wave inverter will most likely cost you more than a modified sine wave inverter, but has the advantage of being able to power advanced, sensitive electronic circuits.

Some digital clocks use the incoming AC current to calculate time. The internal microprocessor ‘counts’ how many times the voltage reaches zero, or ‘zero crosses.’ True sine waveforms cross zero cleanly, whereas modified sine waveforms ‘rest’ on zero for a few milliseconds, as mentioned above.

The microprocessor could read this ‘rest’ as multiple zero crosses resulting in the time being calculated incorrectly. Many electronic devices have built in clocks as part of their functionality.

The more complex or ‘state of the art’ the equipment is, the more likely you are to need a true sine wave inverter. It is important to note that this will include technology such as LED lighting. LED lighting requires electronics to deliver the required voltage or current at a constant rate.

Modified Sine Wave Inverter

True Sine Wave Inverter

  • Vacuum Cleansers
  • Non-automatic washing machines
  • Toasters
  • Kettles
  • Non-LED Lights
  • Power Tools
  • Etc.
  • Personal Video Recorders
  • Electronic Appliances
  • LED Lighting
  • DAB Radios
  • Devices with Electronic Clocks & Timers
    Complex Electronic Eqt.
  • Etc.

True sine wave inverters can power any piece of equipment a modified sine wave inverter can power.

For more information on inverters contact MEAN WELL Australia.