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Frequently Asked Questions


+ What is the difference between Poly and Mono solar panels?

Poly means many and mono means one. In relation to solar panels this is referring to the composition of the individual cells that make up solar panels. The cells are known as wafers and are what convert light to electricity – hence why it’s important to buy a panel with good cells.

Poly cells – are typically blueish in colour and when viewed at different angles show a patchy or jigsaw type appearance. They are typically less efficient than mono panels generally and will convert light to electricity at 15-18%.

Mono panels – are made of a single cell or wafer. These types of cells are usually black in colour and have a better light to electricity conversion rate, typically between 18-21%.

The different conversion rate can mean a big difference to the amount of energy you get out of your solar power system over time. Despite the difference your choice should be made on the quality of the panel. It’s false economy if you buy mono panel that is poor quality.

+ What does battery ready and battery compatible mean?

Battery ready is a term that is widely and loosely used today to suggest that a system is capable of taking a battery storage system. As the prices for batteries are currently high (in 2017) many expect the prices to reduce and therefore wish to install a system that will connect to a battery easily. Truth be told – just about any system that you buy today is “Battery Ready”. I like to take a more specific approach and offer this explanation of battery ready categories.

I suggest two categories, Battery Ready and battery Compatible

Battery Ready – means the installed inverter is able to and can connect to a battery with no additional equipment. Inverter manufacturers such as Sungrow, Solar Edge and Fronius offer true battery ready inverters and are included in our range. These inverters have built in battery communications and management equipment. They are battery ready and can add a battery with some minor programming to tell it how and when to work.

Battery Compatible on the other hand means that the system will manage a battery if you buy and install the compatibility equipment. Things such as a Battery Management System are required to help the inverter communicate with the battery. A battery management system addresses things like when to charge or discharge etc. Using this definition nearly any inverter is battery compatible. See also the section “What is AC Coupling?”

+ What is the difference between ‘On grid’, ‘Off grid’, ‘Hybrid’ & ‘Backup Solar’?

This question is all about inverters and their functionality.

On grid inverters – are the most typical inverter sold in Australia. This type of inverter needs to be connected to the grid – that is plugged in to conventional street power. Once the power goes out so too does the inverter. Solar systems that are grid connected do nothing when the power is out unless you hae aa backup battery system installed. The benefit of on grid however is that they allow the export for credit of power generated and not used. Different power retailers offer different buy back rates for power. Be cautious, those offering bigger credit per Kw will often charge more for the power you buy. More about this in the – What is the difference between Gross and Net Metering section.

Off Grid inverters – allow independent energy use without any connection to street power and are fully stand alone systems with batteries. Off Grid inverters are used with battery power for and are people with no access to conventional poles and wire street power or those who wish to have 100% energy autonomy. These systems can be cheaper than getting grid power to your home using poles and wires or underground. What’s more once installed the power is FREE.

Hybrid Inverters – (or back up inverters as they are also known) are becoming more and more prevalent in Australia today. These types of inverter are connected to street power, but when the street power goes out the go into back up mode to maintain power to your home – usually from solar panels and a battery. The best of these will continue to work independently day in day out until power is resumed. How much power you get depends on how big your system and battery are and how much power you are pulling out of them.

Within these categories there is a high degree of difference in functionality between different brands of inverter and it’s really down to what you are trying to achieve with your solar power system and your budget. We have a range of good options that suit nearly all desired outcomes. Check out our silver bullet soultions for some options.

+ What you should really consider when buying a solar power system?

In the event that something goes wrong with your panels, you want to make sure you’re fully aware of the warranty conditions. The easiest way to ensure this is to read the manufacturer warranty, which can be found on all reputable manufacturer websites. There are download copies of product details and warranties here for easy access. If you are buying a system from us – we will give you the product and warranty information and clearly outline all warranties in your documentation package. Typically Inverters are guaranteed for 5 years and Panels are guaranteed for 10 years with a 25 year guarantee on their performance – HUH, product and performance?

Panel Performance Warranty

Performance warranties or power output warranties relate to panel performance and typically last between 20 and 25 years. These types or warranty will cover repairs/maintenance if your system’s electricity production falls below a predetermined percentage of the panels’ rated capacity as shown on the product information document. For this warranty to apply, panels must be in working order without mitigating circumstance.

The best way to ensure your system is working without fault is to have it checked by a licensed and accredited installer every year. Positive Solar offers service and warranty checks which include a report outlining any warranty or other issues. As well as a written report, we even give your panels a clean to make sure your panels are working at their best. If your system components are reaching the end of their warranty period, get a system check and clean – it could save you big dollars.

Product Warranty

Product warranty relates to manufacturers defects for a given time. These days solar panels typically have 10 years product warranty, though there are exceptions. Inverters are typically guaranteed for 5 years but again there are exceptions.

If you read the fine print of your warranty you will see that in some cases the parts warranty does not cover labour or you will have to pay the cost of getting someone out to your house to take off the panels, or inverter and ship them to the manufacturer, and the pay to install them again, which could cost you more than the equipment value.

Positive Solar is proud to offer SunPower (USA) panels with an industry leading 25-year product and performance warranty covering both parts and labour costs. SunPower, currently the best panels in the world and our premium model, offers a 25-year product and performance warranty with the lowest guaranteed degradation rate of 0.4%. This is great peace of mind and truly a great panel.

Positive Solar is also proud to offer and recommend Fronius (Austria) Inverters which offer a 10 year warranty and Solar Edge Inverters which will offer up to 12 years warranty.

Significant Australian Presence

All our Panel and Inverter range manufacturers have a strong Australian presence. This is essential to ensure warranty is carried out with minimum fuss. It would be very difficult to make a warranty claim against a manufacturer if they have no presence in Australia.

Logically, how much success do you think there would be in calling up an overseas company and demanding they fix your panels? Even if they do agree to do so, you’re going to have to pay thousands of dollars to take them off your roof, ship them to and from China, and install them back on again.

Positive solar only sources panels from manufacturers who have a significant presence in Australia and a great after sales service track record. This provides you with multiple levels of warranty support for the life of your system.

Choose a Quality Inverter

You can install the best solar panels in the world, but if your solar inverter is poor, you won’t be converting anywhere near close to the amount of DC (Direct Current) power your solar panels are producing into usable AC (Alternating Current) electricity.

To ensure your solar system produces great results, Positive Solar recommends choosing a good quality inverter that complies with Australian Standards, has an efficiency of 95% or above, and has a warranty of at least 5 years. Most manufacturers of inverters now manufacture in China and do so to very high standards. For example Zeversolar is manufactured in China by SMA. SMA is one of the world’s most reliable inverter manufacturers. Fronius, (Austria) another excellent inverter choice offers a 10 year warranty! 5 years more than 99% of other manufactures. So it’s horses for courses – get the best inverter for your situation. Inverters are like cars – there is an element of functionality, price and assurances to consider.

Positive Solar is also proud to offer and recommend Fronius (Austria) Inverters which offer a 10 year warranty and Solar Edge Inverters which will offer up to 12 years warranty.

+ How are the savings estimated from solar power systems?

Once you have worked out the average daily output of a solar power system, you can easily calculate your savings year on year. The simple calculation goes like this..

Average daily generation x Your cost of energy during peak and shoulder periods.

So using a 5kw system example and $0.25 cents per kilowatt for power it would be as follows;

5kw x 3.9 (Peak Sun Hours Sydney) = 19.5kW per day x 365 days in the year = 7,117.5 kW per year

Then 7,117.5 kW x by $0.25 cents per kW = $1,779.37 per year in savings.

From here you can also estimate how long it will take for your solar power system to pay itself off. All you need to do is divide the system cost by the yearly savings. Again using the 5 Kw example lets say your system cost $5,500.00. You would divide the savings into the system cost and get the pay back period.

$5,500 system cost / $1,779 savings = 3.09 years

Please note this is the simple formula based on using all the power you generate. It may be the case that you do not use all the energy you generate and some power is exported and credited at your feed in tariff rate.  Also, if you have multiple rates on your energy account these need to be weighted differently to determine your true power cost.

These factors are important because your usage profile is typically different from the generation profile and the art of being a great solar company is getting the size right for your energy us profile. If you have more questions about how more complex calculations are done or would like us to illustrate your energy profile, feel free to contact us using the enquiry form or you can send us a copy of your energy bill and we will do the maths for you – obligation free.

+ How is solar power system energy output calculated?

Ever wondered how the energy output from a solar system is calculated? – well here it is!

  1. The first thing to note is the system size – let’s use an example of ‘5Kw’.
  2. Secondly look up the irradiance levels in your region here.
  3. Thirdly multiply the system size in kW by the irradiance level.

In our 5kW example if you are near Sydney it’s:

5kW x 3.9 peak sun hours = 19.5 kW average daily output.

Why is solar output calculated this way?

Every day is different right? Long hot summer days, short winters days, rainy days and so on. So it’s not really possible to accurately calculate out put on a daily basis as it is subject to prevailing weather conditions.

The Bureau of Meteorology has been logging sun irradiance data for decades. We use this data as it is proven to provide a good estimate on average daily power generation for solar panels in all regions of Australia. You can find out more about how this data is used and collected here.

+ What is an STC?

We have available until 2030 the STC’s (Small scale Technology Certificates) generation scheme. This scheme or incentive works on the premise that the system you buy generates a number of STC’s. Each STC is worth a maximum regulated price of $40 and is subject to market forces below the maximum. It’s a supply and demand market – the more certificates generated by people in Australia installing solar power systems and the closer we get to 2030, the less they are worth.

+ How does a FEED IN TARIFF (FiT) work?

Most Energy retailers offer a solar feed in tariff to their clients. Today this tariff is usually paid to you as an account credit. Different retailers offer different rates to buy the surplus energy that you generate from your solar system.

You can find out more about Feed in Tariffs here.

+ What is the Feed In Tariff (FiT)

The Governments generous feed in tariff scheme largely expired in December 2016 and was based around payments from Energy Providers for power that your solar system generated (AKA – FEED IN TARIFF).

Today fed in tariffs for excess power are still available but much lower than those offered by the Government pre 2016. The difference is however that today Net Meters allow you to use the generated power before exporting surplus whereas previously everything was exported and you bought back what you used. Ideally you should buy a system that does not generate too much power for export as self consumption of your solar power offers the best value.

To illustrate, let’s assume you buy a 5 kW system that generates on average 19.4 kW. If you use this power, it eliminates the need to buy peak or shoulder power at 47 cents or 25 cents per kW. If you sell this power its worth 6-10 cents per kW.

Battery FAQ’s

+ What is AC Coupling?

Simply put, AC Coupling is for people who already have a solar system and wish to add more panels and or batteries. This process involves adding to an existing solar power system a battery, a inverter and sometimes additional panels. It’s like joining two systems together.

Why you may ask? Well if you have an existing system it is covered by warranty. If another installer makes changes to that system it will typically void that warranty. Also, the existing system will need to be upgraded to the most current standard of installation. This can be cost prohibitive and ineffective way to get more juice on the roof or add a battery. These reasons mean that AC coupling is a better option if you have an existing system you want to enlarge or wish to add a battery.

+ What is the difference between ‘On grid’, ‘Off grid’, ‘Hybrid’ & ‘Backup Solar’?

This question is all about inverters and their functionality.

On grid inverters – are the most typical inverter sold in Australia. This type of inverter needs to be connected to the grid – that is plugged in to conventional street power. Once the power goes out so too does the inverter. Solar systems that are grid connected do nothing when the power is out unless you hae aa backup battery system installed. The benefit of on grid however is that they allow the export for credit of power generated and not used. Different power retailers offer different buy back rates for power. Be cautious, those offering bigger credit per Kw will often charge more for the power you buy. More about this in the – What is the difference between Gross and Net Metering section.

Off Grid inverters – allow independent energy use without any connection to street power and are fully stand alone systems with batteries. Off Grid inverters are used with battery power for and are people with no access to conventional poles and wire street power or those who wish to have 100% energy autonomy. These systems can be cheaper than getting grid power to your home using poles and wires or underground. What’s more once installed the power is FREE.

Hybrid Inverters – (or back up inverters as they are also known) are becoming more and more prevalent in Australia today. These types of inverter are connected to street power, but when the street power goes out the go into back up mode to maintain power to your home – usually from solar panels and a battery. The best of these will continue to work independently day in day out until power is resumed. How much power you get depends on how big your system and battery are and how much power you are pulling out of them.

Within these categories there is a high degree of difference in functionality between different brands of inverter and it’s really down to what you are trying to achieve with your solar power system and your budget. We have a range of good options that suit nearly all desired outcomes. Check out our silver bullet soultions for some options.

 

Contacting us

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