Types of solar inverters

Once you decide to go solar, you’ll be welcomed to a plethora of options in the Australian market. The number of solar brands available in the market can become overwhelming for a novice. This article aims to help you better understand what points need to be considered to choose the right solar inverter for your home. There are two categories to consider when deciding on the right solar inverter type:

  1. The solar inverter technology, and
  2. The type of solar power system the inverter is for.

There are a wide range of solar inverters in the solar market with varying sizes, brands, models etc. Choosing the right solar inverter from this large variety of options requires some basic knowledge about them. Some basic knowledge to know and research about the solar inverter you are considering installing for your home or business are as follows –

  • Safety certification :– Whether the solar inverter is certified by any independent testing laboratory
  • Watts: – It is the power used by a device when turned on. The Watt is defined as joules per day. If a device uses 20amps at 12 hours then it is a 120 watts device. It is the product of volts and amps.
  • Watt-hours:- It is the product of how many watts and how many hours the device used. If a 100 watt bulb is used for 8 hours, then it uses 900 watt-hours.
  • Amps: – It is the measure of electrical current at moment. It is defined as 1 coulomb per second.
  • Amp-hours: – It is the product of amps and times. It is the main measure of battery capacity. Most inverters operate using its battery. The Amp-hour capacity determines the battery capacity and it gives an idea about how long it will work.
  • For home; Total Harmonic Distortion (THD) less than 6 percent is sufficient. RMS voltage regulation must be less than or equal to plus or minus 5. Peak voltage regulation must be less than or equal to 10 percent.
  • Efficiency: – The ratio of output power to the input power is termed as efficiency. It is difficult to achieve 100 percent efficiency. Because some power is lost in the form of heat. The efficiency of solar inverter depends on load. The specifications of the inverter contain an efficiency graph. It is the graph of efficiency versus load.
  • Internal protection: – The solar inverter components must be protected from overload, lightning surges, etc. It must contain sensing circuits to sense the problems and automatically shut down. If the supply voltage is less, it must shut off. Otherwise the battery will over discharge and even damaged.

Different types of solar inverters

String inverter:

A string inverter is a single, standalone unit that converts power from a whole string (or strings) of solar panels. String inverters are cheap and convenient, but tend to be the least efficient in situations where there is shading issues on the roof.

String inverter + power optimizer: Power optimizers are attached to each individual panel. They perform MPP tracking at the module level; the optimized DC power is then sent to the string inverter for conversion into AC power. Combining string inverters with power optimizers will increase your cost but allow your system to handle issues like shading better.

Advantages of string inverters

One of the main advantages of a string inverter is that you only need one of them to convert the DC electricity coming from your solar array to AC power. If anything is going to fail in a solar system, it is likely to be the inverter – making troubleshooting relatively easy when things go wrong. Installing a single string inverter on a solar panel installation is cheaper than installing microinverters. Less labor hours are required, and string inverters are more affordable than many microinverters.

Microinverter:

Microinverters are another type of solar inverters. Microinverters are attached to individual solar panels. They perform both MPP tracking and power conversion at the module level, allowing each panel to output usable AC power. They’re especially beneficial in situations when there is shade from trees, etc and have the additional advantage of making your solar system easy to expand. They are, however, the most expensive type of inverter.

Rapid shutdown capability

New electrical codes require rapid solar system shutdown so first responders or firefighters are safe from high voltage when they need to be on rooftops or servicing power lines. Microinverters comply with these rapid shutdown requirements and have this capability embedded into each module.

More electricity

The core advantage of using microinverters is that theoretically, you can yield more solar electricity. The reason for this is that there are slight differences in currents between solar panels. When solar panels are in a string, the current is reduced to that of the least-producing panel in the string.

Suitability for challenging installation conditions

If a solar system is facing multiple angles, meaning some panels are facing south, some east, and some west, then microinverters are the way to go. Or, if you have shading issues from trees or a large chimney, again microinverters would be best.

In these situations, the solar panels will be producing different amounts of electricity at different times of the day, but microinverters will ensure you harvest all of the energy, while with a standard inverter you will lose some of this production.

Microinverters typically have 25-year warranties while standard string inverters typically have a 10 year warranty. Microinverters and the add-on optimizers have the ability to track the production of each individual solar panel, while with a string solar inverter you only can track the production of the whole system. Microinverters are definitely a value-add, but are only recommended if you need to comply with rapid shutdown requirements, have panels facing multiple orientations or you have shading issues. Otherwise, the less-expensive standard string solar inverter is usually more cost-effective.

Contact Austra Solar today for a free quote for the right solar system for your home and begin saving!

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