The components of any grid-connected solar power system ...

There is much more to any home or commercial solar energy system than just the visible componentry. Several elements make up the entire system enabling the array to function reliably and safely. Primary components of the PV array are referred to as, solar modules and the inverter solution. Less obvious but highly essential equipment such as mounting systems, circuit breakers and isolators make up the ‘balance of the system’. 

It is important that each of the key components are designed to work optimally together and not compromise the performance, safety or life expectancy of the other parts. In this article we aim to ease the understanding of what makes up a generic solar power system. Explaining what parts do what and include some tips to help you choose the most optimal solar energy system for your home or businesses requirements. 

 

SOLAR MODULES 

Solar modules are panels that capture the suns energy (sunlight) and convert it to direct current electricity (DC electricity); they are the basis of any solar system.  The DC energy is then fed to the inverter.

A solar panel is made up of several photovoltaic (PV) solar cells and framed. These cells are made up of semiconductors most commonly silicon. Think of a sandwich; two different layers of silicon have been specially treated in order to let electricity flow through in a specific manner. Otherwise known as the Photovoltaic Process. 

The term solar array is used when a series of modules is combined to form a string. Strings in some but not all instances are connected in parallel to make an array. Stringing configurations impact the voltage, current, and power of a solar array. Allowing the selection of an appropriate inverter to match the arrays functionality requirements. 

 

 

60 CELL VS 72 CELL 

The main difference between each of these panels is size. A 72 cell solar panel has an additional 12 cells. In order to cater for the additional cells the panel has to be larger therefore heavier and less ‘user friendly’. Now when I say user friendly I really mean installer friendly. Let’s put this into perspective for you. How do you think solar panels magically appear on your roof? Pure brute strength and muscle power in most cases… 

A 72 cell panel is often, almost 2 meters in length and weights 24kgs and greater depending on the manufacturer. A typical 60 cell panels weigh on average 19 – 20 kgs and typically max out in length at about 1.8 metres. Your probably thinking to yourself now, ‘That doesn’t sound like a massive difference’, well on paper it doesn’t does it. Now imagine climbing a ladder to a double story pitched roof with 20 or more of these panels consecutively. 

In most cases using a 72 cell solar panel on a residential home will not be the most cost-effective solution as they are greater in pricing per watt. If you are limited for space and need to maximise energy yield your installer may insist on using a 72 cell module in order to maximise the available roof space. Be sure to confirm the product warranty is not void by the manufacturer if this panel is installed on your residential home. 

 

 

ADVANCEMENTS IN TECHNOLOGY

The most common solar panel’s being installed on any roof in 2021 are :

•  Mono PERC Half Cell (HC) Panels 
•  N Type Mono-crystalline Panels
•  P Type Mono-crystalline Panels

At the end of 2020 the primary improvement with solar panels was the A-Typical 60 Cell panel being halved and split creating 120 cell panels or greater. 

When it comes down to it the amount of cells your solar module has is not the most important factor. Choosing a solar system that is cost effective, aesthetically pleasing, provides extended product warranties and has a proven efficiency rating are considerations holding significant importance rather than how many cells a solar panel has. 

As we always advise; do your research not all systems are stock standard. Any company providing initial quotations without discussing site specific details and quarterly consumption figures are not interested in providing you a valuable system. 

The overall aesthetics of a module can play a crucial role when deciding what module you want to install on your home. The options are endless, it is important that you discuss this with your solar installation company in depth if you are worried about the ‘look’ of your home. The most common modules currently available are :

• Silver frame with blue cells on white backing sheet.
• Black frame with blue / black cells on white backing sheet.
• Black frame with black cells on black backing sheet   “The Ultra Black”

 

When selecting a solar panel you should consider …

• How long has the manufacturer been trading in Australia for? 
  Should exceed 5 years

• How long is the ‘product warranty’? 
  There are some conniving companies out there who mislead the linear warranty on modules to be the performance warranty. Double check all warranties on the applicable module datasheet. Linear and product warranties are different. 
   
• Is the module on the approved Clean Energy Council module listing?
  For your system to be eligible for applicable government incentives this must be confirmed.
   
• Am I worried how the solar system is going to look on my home?
  We generally recommend an ‘Ultra Black’ full system design for this type of enquiry. Slightly more expensive, but a modern approach to solar design. 

 

SOLAR INVERTERS

The inverter is an essential component of a grid-connected PV system. The photovoltaic arrays or solar modules produce direct current (DC) power. However the electricity grid and most household appliances and electrical devices operate on alternate current (AC) power. 

This is where your inverter plays a crucial role. It ensures the power produced by your solar panels converts the DC power into AC power and allows the electricity generated by the PV system to be fed onto the grid. We like to refer to it as ‘the brains of the whole operation’.  Any crucial error with the brain shuts down operation of the whole system. 

The inverters role in recent years has become more involved than when solar first revolutionised. Advancements in technologies allow for more efficient solar inverters. 

Monitoring systems now allow clients to monitor their solar power production live throughout the course of the day. Additional consumption meters can also be installed in your switchboard allowing you to monitor your families consumption. We highly recommend this feature if you are tech-savvy and want to conserve cost of living expenses.

 

MICRO INVERTERS 

Micro Inverters convert power at the solar panel and are attached to each panel in the solar PV system; working slightly different to a conventional ‘string’ inverter which is usually mounted on a wall in close proximity to your switchboard and connected by DC cable. 

One of the main advantages of Micro-Inverters is; because they are attached to each individual solar panel, they work independently from one another and the DC power generated by the panel is converted directly to AC power immediately at the roof. 

As each panel is optimised individually it allows for maximum power generation. Solar panels can generate different amounts of power due to several reasons, mainly shading and dirt. 

Situations where an optimised system will benefit your site requirements …

• Shading – Trees, buildings, poles, roof structures, chimneys. 
• Layout – Flexible panel orientations and angles for difficult or small roof spaces. 
• Faults – Monitoring each panel allows you to directly corelate which panel has been damaged immediately. Example; hail storms, micro-cracks. 
• Soiling – Debre such as leaves, dust and droppings.
• Ageing – Linear degradation over the lifetime of the product.  
• Design – There are no restrictions with your panel design. 

 

When selecting a solar power inverter you should consider … 

• Product warranty : If something is going to fail, it will be the inverter!
  Most inverters come with a standard 10 year warranty these days with an option to extend. 
   
• Site specific requirements. 
  ​You may be dictated by your home as to what inverter you require. You may have lots of trees surrounding your home causing shading. Your roof structure may be difficult and require the use of more than 2 – 3 angles. This being said you will most likely require an optimised system. 
   
• Your consumption.
  Understanding how much power you and your family are consuming should ultimately dictate the size of the system you install. That is if your roof space can accommodate this of course!

• ​Budget.
  Ultimately your budget will dictate your product. Obtain multiple quotes, always weight up your options by comparing entry-level product and warranties with medium – premium options. There are several options for financing. The most frequently used are low rate ‘green loans’.  

 

BALANCE OF SYSTEM EQUIPMENT

All solar systems require a variety of components other than the PV panels and inverter in order to function.  Collectively they are referred to as the Balance of Systems (BOS) equipment. 

Solar Array Mounting System – The equipment used to secure the PV modules to the mounting structure or roof. Much like a Meccano set. This mounting system also helps determine the PV modules tilt and orientation, directly affecting the power being produced. Also determining the aesthetics of the system. Aesthetics can play a crucial role in the overall look of your system. Black mounting equipment is now available for a more modern approach. 

Cabling – Grid-connected PV systems use DC, AC and earthing cable. Modules come complete with interconnection cables wired from a sealed junction box on the back of the module. Plug and socket connectors at the end of each solar cable allow for easy installation. AC cabling is required to connect the inverter to the AC power grid. Standard earthing cables are used with PV systems. 

Fuses and Circuit Breakers – A fuse is a device that is installed in order to protect against excessive current flows that could damage conductors in a circuit and reduce the risk of fire due to overheating conductors. Circuit breakers are mechanical devices that will open a circuit under fault conditions. A circuit breaker can be manually flipped to close the circuit and restore current flow once the fault has been removed. 

Isolators – An isolator allows equipment to be isolated from electricity and power sources. Allowing the power in a circuit to be shut down.

Metering – An electricity meter records the electricity energy in kWh consumed by loads within the building where the meter is connected. The consumer is then charged for this electricity based on the price set for the consumer. 

System Monitoring - Some PV installations may use a data logger card to measure and record information about the performance of the system. This information is then sent to a central website hosted by the manufacturer and displayed on a monitoring application or portal. 

 

SOLAR COMPANY / INSTALLER

With-out trusted advice, investing in solar power can not only be daunting but highly confusing. You should be buying a quality solar system at a fair price which suits your site requirements and energy demand for years to come. As we always suggest; get multiple quotations that are ‘like for like’ according to product. Discuss with friends and family who have installed solar which company they used and would they recommend them. Do not complete deals over the phone, a site visit should always be completed to verify site specific requirements like shading variants and switchboard compliance. 

 

Avoid companies that :

• Use high pressure sales techniques.
• Door to door salesman.
• Ask you to sign up on the spot.
• Make exaggerated claims.
• Offer systems well under the usual market rate. 
• Say ‘Act now before the government rate ends’
• Can-not explain technical information in ‘plain language’

 

Use our tick and flick cheat sheet when deciding on a reputable installer.

 

Speak with an honest, reputable solar company that can guide you through the process.