Upgrade an existing solar system? Tips and Mistakes to avoid

Looking to upgrade an existing solar panel system? Find out how you should how to upgrade, and avoid common mistakes.

Can You Upgrade An Existing Solar System?

Ever since you went green, you’ve installed a solar system that powers your entire home. The system has been working just fine but you increased your consumption with the addition of a few appliances or machines. Possibly, you developed a new hobby that eats up your power, or some panels just slowed down.

The new electric car you bought recently guzzles up your last watt of power. The stress is evident in the monthly bills, and you have to do something. Fortunately, your roof is spacious enough to support a few more panels, and you are wondering, "can you upgrade an existing solar system?”

Yes, you can upgrade the existing solar system, as long as the upgrades meet the standards outlined by the policies of your state and network provider. The additions must work seamlessly with the existing panels, inverters, or battery storage.

An upgrade can be either a repair or an alteration.

You only repair the specific parts of the system that are worn out. However, the technician can also check if the other parts are working correctly. Repairs aim at restoring the system to the initial standards that existed at the time of installation.

Then, alterations are a strategic change in the way the system works. This could include a few replacements or additions of panels, inverters or batteries. Alteration upgrades aim to improve the system to current standards.

When should you Upgrade Your Solar System?

Your current power output is basically what was enough for you at the time of installation. Over time, you will need to increase your electricity production. Maybe you’ve had a few people move in with you, bought new appliances, or the latest Tesla Cyber Truck- whichever!

Current system doesn’t meet your demand

As long as your current system does not meet your electricity needs, you can upgrade your existing solar array. If you are currently producing lower power kilo-wattage than you need, you can add more panels to your system.

Also, you can replace the old panels with more efficient brands that will convert more sunlight to electricity.

Before you expand your production, consider your consumption, size of your roof, and budget. 

How to Know if Your Solar System Meets Your Power Demands

Sometimes, you could be consuming more power than your solar panels are producing. The information on your application or utility bill receipts should guide you appropriately.

The solar installation company should show how your system should ideally perform. If you notice a sharp difference between the estimated and current system performance, there could be a problem.

Here is how to tell your system is underperforming:

Lower performance than state guidelines

The performance of your solar system depends on your city. Cities that experience more sunlight hours have higher energy generation.

Of course, you have to tilt the angles at the optimum inclination and remove any shadowing. The Clean Energy Council recommends that panels in Australia are inclined at 30 degrees north.

If your system’s average daily output is lower than the ideal city production, you are running an underperforming solar array.  See the ideal average daily output production for different cities in Australia.

Table showing the average daily output per kilowatt of installed solar arrays in different cities


Read your Solar Monitoring App

Solar Retailers normally use applications to monitor your power usage and generation. So, the answer to whether you should upgrade your existing solar array might be right there!

Picture showing the interface of a solar monitoring application.

The application’s interface has invaluable information that will help you make sound decisions. Use it to understand how much power you’re producing. Then, compare the kilowatts you export or import from the grid.

Your utility bills could be skyrocketing every month if you’re importing more power than you export. Consider upgrading your solar system if you want to make the calculations even.

Escalated bills

Your utility bills will possibly be the first indication that something is not right with your system. Read your bills correctly to detect any changes in the monthly charges.

A picture showing a sample utility bill from the Australian Energy company


In case your bills have changed sharply over the last few months, they should raise an alarm. Either your system has issues or your power network provider has spiked the fees.

However, find out if you have new usage patterns such as peak and off peak power use, new appliances or air conditioners. If there’s none, check with your solar retailer or the grid company to determine the root of the problem.

If everything is fine, your current system isn’t meeting your power demands and requires an upgrade. 

The inverter displays an error

Your inverters are the easiest way to tell that something is amiss with your system. Have a routine to check the inverters for any errors.

Picture showing inverter errors

Large Panel Capacity

Add more panels if the inverter has a larger capacity than what it is handling at the moment. The inverter’s rating gets to decide how many more panels you can add to your system.

Flickering Lights

If your lights are flickering more often than normal, check if there’s a burn mark on the breaker box. Find out whether there’s a short in the circuit.  This could mean there’s a component that needs upgrading, repair or replacement.

When the old system doesn’t meet legal standards

 International laws control the quality and safety of solar systems. For instance, the nonpolarized isolator is now a requirement for all systems.

The 2013 IEC 61730 laws set international standards for the safety and efficiency of solar systems.

If you’d set up your current system before 2013, you may have to do an overhaul replacement instead of an upgrade. The standards came with new requirements including a fire rating, and high-density conduit.

The 2015 IEC 62109 brought up an earth fault alarm that informs solar users of any damaged earthing connection.

In Australia, panels must meet the Clean Energy Council (CEC) requirements. Panels that don’t meet these accreditations can stay in their initial installation, but not moved.

Also, technology is far more advanced than it was ten years ago. Before 2012, almost all inverters had transformers but these days they don't. Manufacturers realized they’d save more money by creating transformerless inverters.

Integrating the old solar systems with the new ones is, therefore, a big challenge.

When should you not upgrade, and just buy new solar systems?

Upgrading is, of course, cheaper than buying new systems. But some situations demand an overhaul. The system you have currently may not yield much even after the upgrade because older systems may not meet modern standards.

If the system is more than 20 years old

The warranty of a solar system expires in about 25 years. So, when the system has been around for twenty years or so, you should just have an overhaul. By this time, new technologies exist in the market and you may not want to mix them with the old.

Mixing old and new panels will just cause unwanted stress on the batteries or inverters. Mix-and-match solar systems produce power that’s below their potential.

Seek professional guidance in assessing the system to determine whether you should have an upgrade or an overhaul.

What happens if you include panels with a different model or size?

Including panels with different sizes and models isn’t recommended, but; it’s not forbidden either. Upgrading your solar panels means you may want to get more advanced models or sizes.

First, consult your solar power operator to know whether they allow you to mix and match solar panels. Then, understand how to arrange the photovoltaic cells in series or parallel. Know the implications each format has on your system output.

Panels from various brands have different power ratings, and you have to check if they are compatible with your system.

Using panels from different brands may not have any effect on the system’s performance. However, the characteristics of the individual panels determine the overall output.

Plugging a low-rated panel into your system will drag down the overall power output. The drag is more profound in solar panels connected in parallel than in series. But, no matter how you connect your photovoltaic cells, mix-matching them will reduce your system's production.

Mix-matching solar system components can lead to the loss of power. However, you can mitigate this loss with optimizers and micro-inverters.

This technology treats each module separately within your system. This maximizes the panels' production rates. So, regardless of your panel's size or model, the micros will make the system yield optimal output. 

Do you need to upgrade your inverter as well?

Yes, you can upgrade the inverter of an existing solar system to convert more power. The inverter forms the heart of the solar system. Any increase in the number of solar panels demands an upgrade to the inverter.

The inverter determines how much electricity your system can handle. Whenever you are stepping up or increasing your power output, consider upgrading your inverter, too.

Inverters experience harsh weather conditions as they’re usually installed outside the house.  Installing a high-quality inverter in an enclosed shelter is a brilliant solution to most of the faults.

If panels develop a problem, it will take time before they affect the system. But, in case the inverter stopped working, the whole system would fail.

Chat showing how an inverter works

So, the inverter is literally at the heart of your system and needs an upgrade more than any other component. If you want a seamless supply of solar power to your home, you must have a top-tier inverter.

Upgrade your solar inverter when:

  • If you want to increase your electricity production, consider having an inverter that can support your pursuits.
  • Update your old models for new, more convenient units. Replace the traditional inverter with a micro when you change your roof design. 
  • Check from your monthly utility bills receipt or the digital screen.

Optimizing the Efficiency of Your Solar Inverters

If you have a 5kw inverter, you can add more panels to your system to meet 6kw demand, without replacing the inverter.

Experts recommend that you use inverters with the same capacity as your solar panel output. However, most inverters can support more power than what their rating indicates. 

The efficiency of an inverter depends on the input power. As the DC power from the solar panels increases, the amount of AC power from the other end changes. The inverter only operates optimally within a specific power range.

According to scholars in the Aristotle University of Thessaloniki, the efficiency of a solar panel system inverter is not constant, but depends on the load power.

Here is a graph showing how the loaded DC power from the solar system influences the efficiency of various brands of inverters.


The DC power from your system largely varies with the time of the day and year. So, the inverter needs the capacity to handle higher or lower power than its ideal rating.

However, your inverter can only handle power that’s 30% higher than its rating. For instance, your 5kW inverter should not exceed 6.5kW. Such an inverter is under-sized.

An oversized inverter has a higher nominal capacity than what your solar panel array can produce. In most cases, oversizing inverters is common among homeowners who plan to upgrade their output in the future.

Types of inverters:

String Solar Inverters

A string of solar panels are linked in a series circuit with this inverter. It’s the simplest and most popular among Asian, European and Australian homeowners.

Micro inverters

Micros are inverters attached to specific solar panels so they can operate independently. These inverters are attracting a clique of homeowners with complex roof designs. In short, Micros allow you to put a solar on specific parts of your roofs. Canada and the US are the leading users of Micro inverters. However, these units are pricier and more advanced than other models.

Hybrid Inverters

Combine a solar panel inverter and a battery inverter into a unit and you’ll have the hybrid inverters. Some brands can hold a little power after the blackout, and; this is making them popular among solar enthusiasts.

What are Mistakes to Avoid If You Do Upgrade?

Upgrading an existing system sounds simple on paper, but; knee-deep, it’s sophisticated. Lots of calculations and approaches have to play before you have the system of your dreams.

A good solar company will not rush into giving a simplified quote or promise a haven. Instead, they will let you understand the following issues:

Avoid Losing your Feed-In Tariffs

Upgrading could force you to forfeit the feed-in tariffs (FiT) you’re currently enjoying with the old system.

Check your state’s FiT rules and policies to avoid losing out. Policies change over time. Check any restrictions that govern how you upgrade your solar system.

Calculate whether you’d make more money on the current tariff. Then, consult your provider or power company before you upgrade your solar.

Also, find out if your electricity network provider allows an expansion or approves the new size of power production.

In some cases, you may have to treat the additional panels as a whole new system. You’d keep the existing system's tariffs, but; you’d also incur lots of costs for the new installation. 

Don’t fall for overly nice sales and marketing deals

Sales agents use their psychological marketing prowess to trick you into too-good-to-be-true deals. For example, any agent claiming that upgrading your solar will wipe out all your electricity bills is lying.

Also, the “free solar installation” programs are never entirely free, and there’s always a catch to them. Understand what you’re appending your signature, and don’t fall for enticing offers.

Define your needs before you make the upgrade

Calculate the amount of power your house needs, and avoid unreasonable expectations. If you have a 600-watt refrigerator, you’d need a matching solar kit to power it up.

Remember, your system will only work at around 80% efficiency and only peak sunlight hours. So, here’s a massive difference between the sunlight hours and daytime hours.

Avoid going beyond your size limit

Some jurisdictions have solar system size limits, where your state has a fixed size of solar power that you can produce. Power companies may have the discretion to determine what capacity they will allow from you.

The power companies may decide to charge extra fees to analyze the impact your upgrade can have on their network.

So, upgrade to a size that’s acceptable by your state and power network operator. 

If you do buy new, what will happen to the old panels?

Yes, you can reuse, or recycle the old panels.

Examine your panels and find out if they comply with modern standards. Then you can either sell them or contact your supplier to see if they may want them back. Compliant panels are still useful for on or off-grid systems, and they could fetch you a good price.

However, if they are too old to meet modern standards, you can use them for other work on your property. For instance, they could power up your agricultural activities. You could use them on Recreational Vehicles (RVs), or other non-building mounted systems.

This Reddit user’s father used old solar panels to stop grass from growing to unwanted areas of their yard.

Image showing how old and damaged solar panels are being reused,

Solar panel recycling isn’t so popular, but you may want to talk to your installation service provider or manufacturer for advice.

Can I upgrade my solar system with DIY tweaks?

A DIY solar upgrade would save you hundreds of bucks. However, only licensed electricians can upgrade your solar system. Upgrading the system by yourself- even if you’ve Googled the A-grade blueprint- might attract a harsh legal penalty.

Instead, result in minor procedures such as replacing fuses and performing routine maintenance. Otherwise, contact electrical contractors around your location to do the upgrade for you. Surprisingly, they offer competitive packages.

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