Do you want your solar PV system to produce as much energy as possible? Increasing the array-to-inverter ratio, using a technique known as ‘maximising’, can help ensure you’re getting the most out of your system.
What is maximising?
Maximising is when you install a solar array that has the ability to generate more electricity than your inverter’s maximum output capacity. For example, you can pair a 6kW solar panel array with a 5kW inverter (assuming it is operating safely within the inverter's voltage parameters).
How does maximising work?
Firstly, it is important to understand how solar panels work during the course of a day and also over a 12-month period. It is very rare that you will achieve 3kW output from a 3kW solar array. This is because, in Australia, solar panels generally produce around 80% of their nominal output capacity in the middle of a summer day, and even less during a good day in other seasons. Remember too that this will reduce over the years as the panels degrade.
Along with seasonal differences that occur as a result of fewer daylight hours, your solar array’s output also depends on factors like:
- shade or dust on your panels
- humidity levels
- daily temperatures
- the pitch and orientation of your roof
Next, we need to look at how solar panels are actually rated. The system for determining a solar panel’s maximum output is measured using ‘Standard Test Conditions’. This involves directing 1000 watts per square metre of light at a perfectly perpendicular panel, in a temperature-controlled room ensuring a cell temperature of 25 degrees Celsius and free of loses from things like dust, cables and any degradation. As you can imagine, this is unlikely to occur in a residential setup unless you put some extremely expensive provisions in place. So, for this reason, the panels don’t produce their nominal output capacity in any real world scenario.
Maximise your inverter to increase your solar output
Solar panels generate DC electricity that your inverter turns into AC. Given the likelihood that a regular solar panel installation will only be producing around 50-80% of its maximum level, it makes sense to increase the capacity of your solar array to make up for the shortfall. (So, instead of connecting 5kW worth of panels to a 5kW inverter, we recommend you maximise it with 6kW worth of panels, to maximise the amount of energy your system can harness.)
Good quality inverters can accept more DC power than the maximum capacity of AC they are specified to output. Fronius will actually warrant up to double the DC capacity to AC maximum output, provided it’s done correctly. When maximised, they will increase the voltage and decrease the current of the DC electricity travelling from the solar array. This prevents the output from exceeding the maximum AC level the inverter was designed to handle. Remember as well, the inverter will allow slightly more power coming from the panels than its maximum AC output, which allows for conversion losses within the inverter.
Why is maximising beneficial?
As we’ve already touched on in a previous blog post, maximising your inverter is particularly beneficial, especially if you have panels on different roof orientations.
It is also handy if you have access to Time-Of-Use (TOU) tariffs, as you extend the number of hours your system is producing electricity to include periods when electricity is in high demand (such as later in the afternoon).
Financial benefits are probably greatest for new installs, as the price tag for panels continues to reduce and installation costs are offset by the increased productivity that comes with a larger solar array.
How can I maximise my inverter?
The first step in maximising your inverter is to contact a reputable solar company to inspect your specific needs. Every situation is different, so you need to seek advice from a qualified and experienced installer who can crunch the numbers and design a solar PV system that takes your details into account.
If you’d like to speak with a Solargain consultant about getting the most out of your inverter, you can reach us on 1300 73 93 55 or get in touch with us here.