The concept of oversizing your solar arrays might seem strange at first. However, oversizing can help you produce more energy and save money in the long run. This blog explains what oversizing is, how it works, and whether it’s a good choice for your solar panel setup.
What is Solar Panel Array Oversizing?
Oversizing refers to installing a solar array (a group of solar panels) with a higher capacity than your solar inverter. Typically, solar installers assess your energy consumption patterns and design a system to your exact requirements. However, an oversized solar array intentionally produces more energy than your inverter’s AC output power. This allows your PV system to take full advantage of daylight hours and convert more energy for your home.
The Benefits of Oversizing Your PV Array
Maximise Energy During Daylight Hours
Oversizing enables you to generate more kWh each day compared to when the system is not oversized. It allows you to maximise the number of solar panels on your roof without buying a more expensive inverter. The graph below shows the energy output of an oversized PV system on a summer day with clear skies.
In this example, we have a 6.6-kilowatt array on a 5-kilowatt inverter and an oversized solar array capable of producing 9 kilowatts of power. Since the inverter cannot convert more than 5 kilowatts of AC power, it clips the power generation at 5 kilowatts.
Unfortunately, some power goes to waste when oversizing. In winter there are fewer hours of sunlight and cloudier skies, which will greatly reduce the amount of power the system’s solar array will produce. It’s even possible for the array to produce under the 6.6 kilowatts maximum. This means it wouldn’t make a difference if the system had a 5-kilowatt inverter or a 9-kilowatt inverter on these cloudier days; the system will retain 100% of the energy generated either way.
Higher Inverter Efficiency
Solar inverters work more efficiently near their power limit. By oversizing your solar panel array, your solar inverter will work at its highest efficiency for more hours in the day. The same graph above demonstrates this as well. The area where the 5-kilowatt inverter is clipping is when it’s operating at its highest efficiency. If you had an 8-kilowatt inverter, it wouldn’t work at its highest efficiency for as long.
Oversizing with DC Coupled Batteries
Oversizing is great if your system has a DC-coupled battery. Solar inverters convert DC electricity from the solar panels to AC electricity to power your home or business. As mentioned, the inverter will clip any solar generation greater than the AC power limit. However, if you have a solar battery connected to the DC side of the inverter, your inverter can send that excess power straight to your battery. This way, the oversized solar array can charge your battery quicker without needing a more powerful inverter.
How Much Can You Oversize Your Solar Array?
In Australia, your solar panel array is allowed to be 133% of the size of the inverter and 200% with batteries. For example, you can install a 5kW hybrid inverter with 10kW of panels and a 7kW battery. You can send 5kW to the battery and 5kW to the house grid. There shouldn’t be any safety hazards with oversizing as long as a reputable company designs and installs your entire solar system.
If you’re considering oversizing the PV array for your solar energy system, contact Geraldton Solar Force. Our team will assess your property and find the best solar panel solution for you.
