Updated May 20, 2026
You’ve received a quote and the system looks good and the price makes sense. But one thing stands out: the inverter. Maybe it says 10kW or 5kW, and you’re not sure what that means or if it’s the right size for your home.
It’s completely normal to feel unsure. The inverter is often the most technical part of a solar quote and can easily be overlooked during consultations. Not understanding it doesn’t mean you should just sign and move on.
PSC Energy is Australia’s leading Sigenergy installer. We design SigenStor systems every day across New South Wales, and the inverter size on your quote isn’t just a standard pick. It’s calculated based on your home’s power connection, your battery size, and the number of solar panels you have.
In this article, you’ll learn about the following:
- What a Sigenergy SigenStor Inverter Does
- Why Inverter Size Is Matched to Your Solar Panels
- Single-Phase vs Three-Phase: What It Means for Your SigenStor Solar System
- Why the Sigenergy Inverter Ratio Is Higher Than Standard Solar
- What a Matched SigenStor Setup Looks Like in Practice
- Future Expandability with the SigenStor System
- Four Things Your Solar Installer Checks When Selecting Your Sigenergy SigenStor Inverter Size
- FAQ: Sigenergy SigenStor Inverter Sizes and Selection
By the end, you’ll understand the number on your quote and know what questions to ask before you sign.
What a Sigenergy SigenStor Inverter Does
Your solar panels produce direct current (DC) electricity, but your home runs on alternating current (AC). The Sigenergy SigenStor inverter sits in between and converts the power so your home can use it.
Without an inverter, the electricity from your solar panels can’t power your lights, fridge, air conditioning, or anything else at home. It also can’t be sent back to the grid. All electricity passes through the inverter first.
The inverter size, measured in kilowatts (kW), tells you how much electricity it can convert at once. For example, a 10kW inverter can handle up to 10kW of electricity at any moment. This affects how much solar power your home can use or send to the grid right away.
The SigenStor is a hybrid inverter, which means it manages three things:
- Converting solar energy from DC to AC so your home can use it.
- Charging your battery from the solar panels.
- Drawing stored energy from the battery and converting it back to AC when you need it.
This three-way function is what sets SigenStor apart from a basic solar inverter. It also lets you have a higher ratio of solar panels to inverter size, which we’ll explain soon.
If you’d like to learn a bit more about the cost of SigenStor, we recommend you check out the following article titled, How Much Does the Sigenergy SigenStor Cost?
Why Inverter Size Is Matched to Your Solar Panels
In the solar industry, it’s common to install more solar panel capacity than the inverter’s rating. This is called oversizing and it serves a specific purpose.
It’s like buying pyjamas. You don’t pick the exact size that fits, you choose a slightly bigger size for comfort and room to move. Solar panels and inverters work in a similar way.
Solar panels almost never produce their full rated output all day. Clouds, the sun’s angle in the morning and evening, and shading all reduce how much power they make. If you matched the inverter size exactly to the panels, it would only run at full capacity for a short time each day.
By installing more panels than the inverter’s rated capacity, you:
- Keep the inverter running near its optimal output for more hours each day.
- Generate useful electricity on cloudy days and through winter months.
- Maximise your system’s performance all year, not just at midday on a clear summer day.
The SigenStor inverter sizes available through PSC are:
Single-phase: 6kW and 10kW
Three-phase: 5kW, 10kW, 15kW, 20kW, 25kW, and 30kW
This range covers everything from a modest single-phase home to a large three-phase property with high energy needs. The right inverter size depends on your connection type, battery size, and solar needs.
If you’re interested in learning a bit more about oversizing, you might want to check out the following article titled, Oversizing Your Solar Panel System: How to Maximise Your Panels for Bigger Returns.
Single-Phase vs Three-Phase: What It Means for Your SigenStor Solar System
Your home connects to the electricity grid through either a single-phase or three-phase supply. That connection type sets the rules for how large an inverter you can install and how many solar panels you can connect.
Single-phase power uses two wires: one active wire carries current into your home through your appliances, and one neutral wire carries it back out. Many standard residential properties in Australia have a single-phase supply.
Three-phase power uses three active wires and one neutral wire. Each active wire carries power in turn, and the three waveforms overlap each other throughout the electrical cycle.
This overlapping pattern gives your home a steadier, more continuous power supply. That’s why three-phase connections allow for larger inverter sizes without putting extra strain on the grid. Three-phase power is common in bigger homes, properties with high energy use, and commercial buildings.
The SigenStor solar system uses different panel-to-inverter ratios depending on your connection type:
- Single-phase: the SigenStor supports up to 200% oversizing of solar panels. A 10kW inverter can support up to 20kW of solar panels.
- Three-phase: the SigenStor supports a 1.6 ratio. A 10kW inverter can support up to 16kW of solar panels.
The single-phase ratio is higher because, with battery storage, extra solar can bypass the inverter and charge the battery directly as DC. We’ll explain how that works in the next section.
If you’re interested in learning a bit more about single-phase and three-phase sites, you might want to check out the following article titled, Single-Phase vs. Three-Phase: How Are They Different?
Why the Sigenergy Inverter Ratio Is Higher Than Standard Solar
A standard solar system without a battery follows a 1.33 DC-to-AC ratio. For a 10kW inverter, that means up to 13.3kW of solar panels. Grid rules set this limit to prevent the inverter from overloading during peak sunlight.
The SigenStor changes this because it’s a hybrid system. Here’s the key difference:
- In a standard solar-only system, all electricity from the panels must flow through the inverter before it becomes usable.
- In a hybrid system like the SigenStor, excess DC power from the panels is fed directly into the battery, bypassing the inverter.
Sending DC power straight to the battery skips a conversion step. With fewer conversions, less energy is lost, and the inverter isn’t overloaded by a larger panel array.
Here is a practical example. Say you have 20kW of solar panels connected to a 10kW single-phase SigenStor inverter:
- Up to 10kW flows through the inverter to power your home directly.
- At the same time, up to 15kW is sent directly to the battery, bypassing the inverter.
- Over one hour, that is 15kWh of stored energy available after the sun goes down.
This ability to charge the battery directly is exactly why the Sigenergy inverter ratio can exceed the standard solar limit. The battery efficiently absorbs the overflow, so the larger panel array generates more energy without wasting any.
If you’d like to learn a bit more about SigenStor, a solar battery we carry, we recommend you check out the following article titled, Sigenergy SigenStor Review.
What a Matched SigenStor Setup Looks Like in Practice
Matching your inverter, battery, and solar panels properly ensures reliable performance all year.
- If your inverter is too small for your battery, charging will be slow and the battery might not fill up on short winter days.
- If the inverter is too large for your panels, it will sit idle more often than needed.
Here are two typical SigenStor setups PSC recommends:
Setup 1: 16kWh of battery storage
- Inverter size: 5kW
- Solar panel capacity: 8kW
- Suited to homes with moderate energy use. The 8kW array keeps the inverter near full output during sunny hours and charges the 16kWh battery reliably across most of the year.
Setup 2: 24kWh of battery storage
- Inverter size: 10kW (minimum)
- Solar panel capacity: around 9kW
- The larger battery requires a larger inverter to fully charge it on a typical winter day. A 5kW inverter paired with 24kWh of storage would struggle to top the battery up before another night of discharge.
Getting this balance right is one of the most important parts of designing a SigenStor system. That’s why PSC customises every system instead of using a standard package.
If you’d like to learn a bit more about Sigenergy’s SigenStor, you might want to check out the following article titled, Pros and Cons of the Sigenergy SigenStor Solar Battery and Energy System.
Future Expandability with Sigenergy SigenStor
One of the best things about the SigenStor is its modular design. You can start with a smaller battery and add more modules later as your energy needs grow or your budget allows.
Here is what you can change later:
- Battery capacity: Additional SigenStor battery modules can be added to your existing system without a new inverter, provided the added storage stays within the inverter’s supported range.
- Solar panel capacity: You can add more panels later if your inverter has room under the oversizing ratio. For example, a 10kW single-phase inverter supports up to 20kW of panels, so if you start with 12kW, there’s still room to add more.
Here is what is better decided upfront:
- Inverter size: You can change the inverter later, but it costs more and takes extra time to install. Picking the right size from the start saves money in the long run.
- Battery expansion plans: If you plan to add a lot more storage in the future, your first inverter needs to support that extra capacity. Let your installer know if you’re thinking about expanding your system in five years, as that will change our recommendation.
Homeowners with a mismatched system often end up relying more on the grid than they planned, or needing to replace the inverter sooner than expected.
If you’d like to learn about some of the potential downsides to the SigenStor energy system, you might want to check out the following article titled, Problems with Sigenergy SigenStor Solar Energy System.
Four Things Your Solar Installer Checks When Selecting Your Sigenergy SigenStor Inverter Size
When PSC designs your SigenStor system, we look at four main factors before recommending an inverter size.
1. Your home’s energy demand. We look at your electricity bills to understand how much energy you use each day and when you use it. A single-phase home with moderate usage will rarely need anything larger than a 10kW inverter. A three-phase home running ducted air conditioning, a pool pump, or heavy appliances may need 15kW or more.
2. Your available roof space and panel capacity. More roof space means more panels, which in turn require a larger inverter to make the most of them. Your installer checks your available roof area and orientation before landing on a panel count, then selects an inverter sized to suit that array within the applicable oversizing ratio.
3. Your battery storage plans. The battery size drives the minimum inverter requirement. As shown above, a 24kWh battery needs at least a 10kW inverter to charge reliably. Your installer matches the inverter to the battery first, then optimises the panel count around it.
4. Your grid connection limits. Your local Distribution Network Service Provider (DNSP) sets rules on inverter size and how much power you can export to the grid. Your installer checks these limits before finalising your design. In some cases, an export limiter is required to comply with DNSP rules while still getting the full benefit of a larger solar array.
If you’d like to learn a bit more about Sigenergy’s SigenStor, you might want to check out the following article titled, Pros and Cons of the Sigenergy SigenStor Solar Battery and Energy System.
Wrapping Up: Just One of Those Phase(s)
The inverter is the part of your SigenStor system that connects everything.
It converts DC electricity from your solar panels into AC electricity for your home, charges your battery from the panels, and draws stored power from the battery when you need it.
Oversizing your solar array relative to the inverter is standard practice and improves performance year-round, not just on the sunniest days.
PSC Energy is Australia’s number one Sigenergy installer. Every system we design is built around your actual energy use, your home’s connection type, and your goals for energy independence.
If you want to go through your quote in detail, or you’re still deciding on the right system size, get in touch with the PSC team. We’ll help you get it right. It’s what we do.
If you’re interested in learning more about the changes to the federal battery rebate, you might want to check out the following article titled, Is the Federal Battery Rebate Still Available?
FAQ: Sigenergy SigenStor Inverter Sizes and Selection
What does a Sigenergy SigenStor inverter do?
The SigenStor inverter converts the DC electricity your solar panels produce into the AC electricity your home uses. As a hybrid inverter, it also charges your battery from the panels and draws power from the battery when the sun is not generating. All electricity in your solar system either flows through the inverter or bypasses it on the way to the battery as DC.
What Sigenergy SigenStor inverter sizes are available through PSC?
For single-phase homes, the available SigenStor inverter sizes are 6kW and 10kW. For three-phase homes, the options are 5kW, 10kW, 15kW, 20kW, 25kW, and 30kW.
Why is the single-phase oversizing ratio higher than the three-phase ratio?
Single-phase homes can oversize to 200% because excess DC solar energy is routed directly to the battery, bypassing the inverter and preventing overload. Three-phase homes use a 1.6 ratio because power is distributed across three circuits, and the grid rules for three-phase connections differ. Three-phase is not a worse outcome, it supports much larger inverters overall, which means more total panel and storage capacity.
Can I add more solar panels to my SigenStor system later?
Yes, within the oversizing ratio for your inverter size. A 10kW single-phase inverter supports up to 20kW of panels in total. If you want to add panels beyond what your current inverter supports, you may need to upgrade the inverter at the same time.
What happens if my Sigenergy SigenStor inverter is too small for my battery?
Your battery will charge slowly and may not reach full capacity on short winter days. Over time, that means drawing more from the grid during evenings than you planned. Your installer sizes the inverter to the battery first to avoid this outcome.
What is the difference between the Sigenergy inverter ratio and a standard solar system?
A standard solar-only system follows a 1.33 ratio. For a 10kW inverter, that means up to 13.3kW of panels. The SigenStor allows ratios of 2.0 (single-phase) and 1.6 (three-phase) because excess DC solar energy can bypass the inverter and go directly into the battery. That bypass is what makes the higher ratio safe and efficient.
Is the SigenStor inverter size fixed once installed?
Yes. The battery modules are modular and can be added to later. The inverter itself is a fixed part of the installation. Choosing the right inverter size upfront matters, particularly if you plan to grow your battery storage over time.
What does a DNSP have to do with the size of my SigenStor inverter?
Your Distribution Network Service Provider (DNSP) is the company that manages the power lines in your area. They set rules on how large an inverter you can connect to the grid and how much power you can export. Your installer checks these limits before finalising your system design to make sure your installation is compliant from day one.
