Is My Solar Working? 6 Simple Checks for Commercial Solar PV Systems

It sounds like a simple question, but after years of working with solar PV systems, I've learned the answer isn't always as obvious as you'd think. I've investigated systems that were completely switched off. I've found inverters that had been tripping for weeks without anyone realising. I've looked at solar and battery systems that were technically "working" but configured in a way that was actually costing the client money.

And one of the worst examples I've come across: I once put my head into a lady's loft in Manchester because she thought there might be something wrong with her solar. There was. Her inverter was still in the box. It had never even been installed. She'd been living in the property believing she had a working solar PV system.

That story sums up why I think every solar owner — particularly every business with commercial solar — needs to ask one simple question: how would you actually know if your solar stopped working today? Because the most expensive solar fault isn't necessarily the biggest fault. It's the one nobody notices.

In this guide, I want to walk through six different ways to check whether your solar PV system is working — from something almost anyone in a business can do, right through to professional diagnostics. More importantly, we'll look at how quickly each method would actually identify a problem, because there's a huge difference between discovering a fault a month later, the following day, today, or the moment it happens.

If you're a business owner, energy manager, utilities manager, facilities manager, maintenance technician — or simply the person who's just been told "can you find out whether the solar is actually working?" — this guide is for you.

First: "Working" Doesn't Necessarily Mean "Working Properly"

This is probably the most important distinction in the whole article. A solar PV system can be generating electricity without performing correctly. One inverter could be offline while others carry on. A string could be underperforming. Monitoring could be disconnected. A battery could be charging at completely the wrong time. The system could be importing electricity when it shouldn't be, or exporting valuable electricity without being correctly set up to get paid for it.

So there are really two questions here: is my solar generating electricity, and is my solar performing as it should? Those aren't the same thing. Let's start with the simplest checks.

1. Check Your Electricity Bill — But You Could Already Be a Month Too Late

One of the first places people look when they suspect their solar isn't working is their electricity bill, and it can provide useful clues. If your grid consumption suddenly increases significantly, something may have changed — solar generation may have reduced, an inverter may have stopped, a battery may no longer be operating correctly, or your building's own consumption may simply have gone up.

The weakness is that you're looking backwards. By the time your bill arrives, the problem may have existed for weeks. If you're billed monthly, you could lose a full month of solar generation before anyone notices — and once that sunshine's gone, you can't get it back. You can fix the inverter today, restore the monitoring today, repair the system today. But you can't go back and regenerate last month's sunshine.

A commercial system that hadn't worked properly for around two months.

We recently reviewed a commercial situation where the client's solar hadn't been operating correctly for around two months. To make it worse, the client had previously been advised onto an electricity tariff costing around 35p per kWh, and the solar should have been covering a substantial chunk of the building's summer demand. Instead, it wasn't delivering. With electricity costs running at roughly £3,500 a month, the combined impact of extra electricity purchases, lost generation and potentially lost export value was substantial — potentially approaching £9,000, depending on the exact profile. The sun had been shining. The opportunity was there. Nobody had caught the problem in time.

Your electricity bill can tell you that something went wrong. It just might tell you far too late.

Need help understanding whether your solar is actually reducing your electricity bill? Independent Solar Consultants can compare your electricity consumption, solar generation and available monitoring data to help establish whether your system appears to be delivering what it should.

2. Check Your Solar Generation Meter — Know Whether It Generated Yesterday

Let's move a step closer to real time. Instead of waiting for your next bill, find your solar generation meter. Depending on the age and design of your system, this might be a dedicated meter recording the AC electricity generated by your PV installation, or generation may be recorded through another compliant metering arrangement. MCS solar PV standards include requirements around having a means of recording and displaying total AC generation, which is one reason generation data is such a useful starting point.

You don't necessarily need specialist test equipment for this first check. Photograph the meter reading today. Come back tomorrow and photograph it again. If the reading's increased, the system has generated electricity between those two points. That doesn't prove every panel, string or inverter is performing correctly — but it answers the first basic question: has my solar generated anything at all? For a facilities manager, caretaker, site manager or energy manager, this is an easy check to build into a routine inspection.

Different installations use different meters and arrangements, so if you're unsure which meter relates to your solar, don't start opening electrical equipment — get somebody competent to identify it for you.

The Manchester solar system that had never worked.

This is probably the saddest solar fault I've come across. I attended a property on a new-build estate near Manchester where the homeowner believed something was wrong with her solar. She'd been living there for around a year and a half to two years believing the system was operating. I put my head into the loft expecting to inspect the inverter, and there it was — still in its box. It had never even been properly installed and commissioned. She thought she had solar. She had panels on the roof. But the system had never done what she believed it was doing. Depending on expected generation, electricity prices and the historic tariff arrangements involved, the financial impact potentially ran into several thousand pounds in lost savings and lost generation-related income. She was understandably gutted — and a simple generation meter check could have raised the alarm almost immediately. You shouldn't need to wait two years, or even two months. You just need to check whether the meter's moving from one day to the next.

3. Check Your Solar Monitoring Portal — Know What Is Happening Today

Most modern commercial inverters have some form of monitoring capability — a Wi-Fi dongle, Ethernet connection, data logger, communications gateway, manufacturer cloud portal, or a third-party monitoring platform. If your system has monitoring, you should know where it is, who has the login, whether it's online, and who actually checks it. These sound like basic questions, but you'd be amazed how often we investigate commercial solar systems where nobody can answer them. The installer set up the portal. An employee who's since left had the login. The Wi-Fi password changed. The dongle went offline. The monitoring account still belongs to the original installer. Or nobody was ever given access in the first place.

Many modern inverters come with manufacturer monitoring as part of the system ecosystem, and for a straightforward installation, access to that basic monitoring should normally be set up as part of commissioning. That's a different thing from professional monitoring services involving multiple sites, automated alerts, active fault response, data aggregation, API integrations, portfolio dashboards and long-term analytics — those legitimately involve additional infrastructure and ongoing management. But if nobody in your organisation has access to even the basic inverter monitoring, that's worth investigating.

A £1 million commercial installation with inverters tripping.

I've been involved in reviewing a large commercial solar installation representing an investment of around £1 million at the time it was installed — I'll keep the client and project details anonymous, but the lesson is the important part. Inverters were tripping, the system wasn't operating as expected, and the problem wasn't being picked up quickly enough. On a system that size, downtime isn't a small problem — depending on generation conditions and electricity values, the financial impact can run into thousands of pounds per week. A business can spend hundreds of thousands, or even close to a million pounds, on renewable energy infrastructure, and then everyone simply moves on to the next project. Then something trips, and nobody notices quickly enough.

Ask yourself: if one of your commercial solar inverters stopped at 11:17 this morning, when would somebody in your business actually know? Today, tomorrow, next month, when the bill arrives — or never? That answer tells you a lot about how well your solar asset is being managed.

Lost access to your solar monitoring? We help businesses investigate existing solar PV systems, restore monitoring where possible, and establish what information is actually available from the installed equipment.

4. Automate Your Solar Monitoring — Know When Something Changes

Now we move from "can I log in and check my solar?" to "why should somebody have to remember to check it at all?" This matters most for commercial organisations. Imagine you're an energy manager responsible for 20 buildings, a utilities manager overseeing 50 sites, or a property company with 100 roofs carrying solar PV. Are you realistically logging into 100 different inverter portals every morning? Probably not — and even if you did, what exactly would you be looking for? A red light, zero generation, an offline inverter, generation running 20% below expected, unexpected grid import, a battery charging at the wrong time, a communications fault?

This is where automated and bespoke monitoring earns its keep. Instead of relying on somebody remembering to check, the goal should be making the data come to you. Instead of asking "when did somebody last check the solar?", the better question is "who gets alerted when something goes wrong?" A properly designed monitoring strategy can bring together PV generation, inverter status and alarms, grid import and export, battery state of charge and behaviour, building consumption, abnormal performance and communications status — though exactly what's available depends entirely on the installed equipment and metering architecture. The principle stays the same: measure it, monitor it, identify exceptions, act quickly.

Multi-site solar changes the problem completely.

One solar system can often be checked manually. Fifty cannot. We increasingly see businesses that have invested heavily in solar across their estate but end up with every site running something different — different inverter manufacturers, different monitoring portals, different usernames, different installers, different generations of technology. Some sites are online, some aren't. Some have generation meters, some have additional metering, some have batteries. Nobody has one clear picture. The organisation technically owns a solar portfolio, but operationally it may be managing dozens of isolated systems — and that creates risk, because when something fails, the first challenge is simply discovering that it has.

At Independent Solar Consultants, this is one of the areas we help businesses with: understanding what monitoring already exists, what data can be recovered, and how multiple sites could be brought into a more useful monitoring strategy.

5. Look at the Inverter — What Is It Telling You Right Now?

If you want to know what your solar is doing right now, the obvious place to look is the inverter itself. Most have some form of status indication — indicator lights, an LCD screen, status codes, warning symbols, audible alarms, or information available through an app. You might see a green light and think "happy days, solar's working." Possibly. But be careful: a green status light doesn't necessarily prove the entire array is performing correctly. Different manufacturers use different indicators, one inverter could be running while another on the same site is offline, and a system could be generating while one input or string underperforms, or while the battery controls are set up wrong. Treat the inverter status as one piece of evidence, not the whole diagnosis — and always check the correct manufacturer guidance for your specific make and model before interpreting any warning lights or fault codes.

When solar isn't just failing to save money — it's actually costing you money.

We investigated a commercial system with solar PV and battery storage where, at first glance, there was technology everywhere that should have been saving the client money: solar, battery storage, controls, monitoring. The problem was that none of it had been configured correctly. The monitoring and control strategy were wrong, the battery was charging and discharging at inappropriate times, and different parts of the system were effectively working against each other. Under certain operating conditions, the solar itself wasn't behaving as intended. The estimated financial impact was approximately £65–£70 per day — run that across a month, then a year, and a system designed to cut electricity costs becomes an expensive problem instead.

This is why "is there a green light on the inverter?" isn't really the right question. The better one is "is the entire energy system behaving as it was designed to?" Solar, battery, grid, building load, export controls, tariffs and monitoring all interact — and as commercial energy systems get more sophisticated, good monitoring only becomes more important, not less.

Solar or battery system behaving strangely? Independent Solar Consultants can independently review solar PV, battery behaviour, monitoring data and system configuration to help establish whether the equipment appears to be operating as intended.

6. Professional Solar Testing — Prove What Is Actually Happening

Eventually you move beyond visual checks and monitoring into actually testing the system. This is where a competent solar engineer or electrician carries out proper diagnostic work, which might include AC and DC current measurements, string comparisons, inverter output checks, voltage measurements, insulation resistance testing where appropriate, generation meter verification, CT orientation and metering checks, export limitation checks, battery behaviour analysis, monitoring data analysis, expected-versus-actual generation comparisons, thermal inspection and physical inspection of equipment and connections. A DC clamp meter, for example, lets a competent person measure current on PV circuits without disconnecting them.

This is firmly competent-person territory, though. Solar PV arrays produce DC electricity whenever they're exposed to light, and commercial installations can involve significant DC voltages and currents. Don't start opening inverters, disconnecting DC connectors or accessing live electrical equipment because you've watched a video about checking solar — there's a big difference between looking at your generation meter and electrically testing a live commercial PV system.

The Six Levels: How Quickly Would You Know Your Solar Had Failed?

Put together, these six checks form a kind of ladder, and it's worth seeing them laid out that way:

• Level 1 — Electricity bill. You may discover the problem weeks or a month later. Useful, but retrospective.
• Level 2 — Generation meter. You can potentially know by tomorrow. Take a reading today, compare it tomorrow.
• Level 3 — Monitoring portal. You can see what happened today, assuming the monitoring itself is online and accurate.
• Level 4 — Automated monitoring. You can potentially know the moment something changes — particularly valuable for commercial and multi-site portfolios.
• Level 5 — Inverter status. You can see what the inverter is reporting right now — useful for immediate fault indication, but not proof the whole system is performing correctly.
• Level 6 — Professional testing. You can establish what's actually happening electrically and operationally. This is where you move from "I think something's wrong" to "here's the evidence."

What About Export? Is Your Solar Generating Electricity You Aren't Being Paid For?

There's another side to checking whether your solar is working: what happens to the electricity you don't use? Depending on your installation, metering, eligibility and contractual arrangements, surplus electricity may be exported to the grid. For eligible installations under the Smart Export Guarantee, electricity suppliers offer tariffs that pay generators for qualifying exported electricity, and Ofgem confirms that generators wishing to receive SEG payments need to apply to an appropriate SEG licensee and meet the relevant eligibility requirements.

Generating electricity and getting paid for exported electricity are not the same thing. You can have solar generation, bill savings through self-consumption, and export income — but they're separate parts of the financial picture. For older installations, historic Feed-in Tariff arrangements may also apply, including generation and/or export payments depending on the specific installation and registration. That's why documentation matters. If you've inherited responsibility for a commercial building with solar, it's worth establishing who owns the system, when it was installed, what tariff or incentive arrangements apply, whether there's an export MPAN where required, who receives export payments, where meter readings are recorded, who has monitoring access, and where the commissioning documents actually are. Don't assume any of this was done properly just because there are panels on the roof — I've seen enough systems to know that assumption can be expensive.

"But My Solar Is Generating — So Surely It's Fine?"

Not necessarily, and this is one of the biggest misconceptions around existing solar PV. Imagine a commercial system expected to produce 100 units of electricity that's actually producing 55. Is it working? Technically, yes. Is it working properly? Possibly not. A generation meter increasing proves electricity has been generated — it doesn't prove the system is producing what it reasonably should be. There may be inverter faults, string faults, shading changes, failed components, communications issues, soiling, degradation, incorrect settings, export limitations, battery-control issues, or simply changes to the building's electrical demand behind that number. This is where expected-versus-actual performance analysis becomes genuinely valuable.

How Much Money Can a Solar Fault Cost?

There's no single answer — it depends on system size, time of year, electricity tariff, self-consumption, export tariff, length of downtime, battery operation and the nature of the fault itself. But our real-world experience gives a sense of scale. A Manchester homeowner believed her solar was operating for around two years while the inverter sat uninstalled in its box — a potential impact of several thousand pounds in lost savings and lost historic tariff income. A large commercial installation representing around £1 million in investment suffered inverter trips that weren't addressed quickly enough, costing potentially thousands of pounds per week during significant downtime. A solar-and-battery system with incorrect configuration cost an estimated £65–£70 per day by working against its own intended strategy. And a commercial client on a 35p/kWh tariff, paying around £3,500 a month, lost roughly two months of expected summer solar performance — a combined impact potentially approaching £9,000.

These figures aren't universal outcomes; every system is different. But they demonstrate something important: solar downtime has a real financial value, and the larger the system, the more important the speed of detection becomes.

Who Should Be Responsible for Checking Commercial Solar?

This is a question businesses often overlook. The installer installs it, the project completes, everyone celebrates — then what? Who owns the responsibility the following Monday morning? For a small business it might be the owner. For a larger organisation, it might sit with an energy manager, utilities manager, facilities manager, estates manager, maintenance manager, property manager, sustainability manager, finance team, or external facilities-management provider. Sometimes nobody knows, and that's dangerous — if responsibility belongs to everyone, it often belongs to no one.

Someone in the business should know how to access the monitoring, what normal generation roughly looks like, what happens when an alarm occurs, who to contact when something fails, where the system documentation is stored, and how quickly a fault needs to be escalated. For multi-site organisations, that process should ideally be systematic rather than relying on somebody remembering to log into individual portals.

A Simple Monthly Commercial Solar Checklist

If you're responsible for solar within a business, start here. Check whether the generation meter has increased as expected. Check that the monitoring portal is online and every inverter is communicating. Check for unresolved inverter or battery alarms. Check whether generation looks broadly sensible against previous periods and expected seasonal performance. Check whether grid consumption has unexpectedly increased. If you have batteries, check they're charging and discharging when expected. Check that export is being recorded correctly where applicable, and that any expected export payments or tariff benefits are actually being received. And finally, check that somebody actually knows who needs to act if something's wrong.

You don't need to understand every electrical detail. You just need a process capable of flagging when something needs investigating.

Frequently Asked Questions

How do I know if my solar panels are working? Start by checking whether your solar generation meter is increasing and whether your inverter or monitoring portal shows current generation. For a simple check, photograph the meter reading one day and compare it the next. Remember that generation proves the system is producing some electricity — it doesn't necessarily prove the entire system is performing correctly.

Why are my solar panels not generating electricity? Possible causes include inverter faults, grid faults, isolators being switched off, communications problems, wiring or string faults, protection devices operating, equipment failure or other system issues. Generation also naturally varies with weather, season, orientation and shading. If generation has unexpectedly stopped, get the system investigated by a competent person.

Should my solar inverter have a green light? Many inverters use green lights to indicate normal operation, but status indicators vary by manufacturer and model — always check the manufacturer's instructions. A green light also doesn't necessarily prove every part of a larger PV system is operating at full performance.

Why has my electricity bill increased even though I have solar panels? Several possible reasons: your consumption may have increased, solar generation may have reduced, an inverter may have failed, your battery may not be operating correctly, your tariff may have changed, or your monitoring may simply be giving you an incomplete picture. The best approach is comparing grid consumption, solar generation and, where available, half-hourly or monitoring data.

Can solar panels stop working without me knowing? Absolutely — we've encountered systems where faults went unnoticed for extended periods, particularly where monitoring is offline, nobody's responsible for checking generation, or a business relies solely on electricity bills to spot changes.

How often should commercial solar be monitored? It depends on system size, financial exposure and operational importance. For larger commercial systems, relying solely on occasional manual checks can leave significant periods of downtime unnoticed. Automated alerts and centralised monitoring can substantially shorten the time between a fault occurring and somebody becoming aware of it.

Can one inverter fail while the rest of the solar keeps working? Yes. Larger commercial PV systems often use multiple inverters, and one can stop while others continue generating. From a distance, the system may appear to be working fine while a significant proportion of generation has actually been lost — which is why total generation and individual inverter performance should both be considered where monitoring allows.

How can I monitor solar across multiple commercial sites? It depends on the equipment installed at each site. Some organisations end up with multiple manufacturer portals, while others use centralised metering or bespoke monitoring platforms to aggregate data. The first step is normally auditing what equipment, meters, communications and monitoring access already exist before deciding what needs replacing or integrating.

Who can independently check whether my commercial solar is working? An independent solar consultant or suitably competent solar PV professional can assess the system without being tied to selling replacement equipment. Depending on the issue, this might involve reviewing electricity bills, generation records, inverter monitoring, battery data, metering, system documentation and physical or electrical testing.

Is My Solar Working? Start With These Three Things

If you've reached this article because you genuinely don't know whether your commercial solar is working properly, don't panic and don't start replacing equipment. Start by gathering evidence. Find a recent electricity bill — ideally several, so consumption can be compared over time. Take a photograph of your solar generation meter, including the current reading and, if possible, the meter make and model. And pull screenshots from your solar monitoring portal, including current generation, recent historical generation and any alarms or warnings. Those three pieces of information can often tell us a surprising amount about where to start.

How Independent Solar Consultants Can Help

At Independent Solar Consultants, we work independently across existing solar PV and battery installations — we're not tied to one inverter manufacturer or one installer's equipment. Depending on your situation, that can mean an independent solar health check and fault investigation if you suspect something isn't working, monitoring restoration and investigation if your portal's gone dark or the login's been lost, or bespoke commercial and multi-site monitoring if you're managing a portfolio of installations and need one clear picture instead of a dozen disconnected ones. This is particularly relevant for commercial property portfolios, utilities teams, energy managers, facilities-management organisations, care groups, schools and education estates, charities and churches, industrial businesses, landlords, and any organisation with multiple renewable energy assets.

Final Thought: The Most Expensive Solar Fault Is the One Nobody Notices

Solar PV is incredibly passive, and that's one of its greatest strengths — there are no engines running, nobody has to stand beside it all day, the panels sit on the roof and generate electricity. But that passive nature is also a weakness. It's very easy to forget about, and forgotten assets can quietly stop delivering value.

I've seen a homeowner believe she had working solar when the inverter was still sitting in its box. I've seen a major commercial solar investment lose substantial amounts because inverter faults weren't caught quickly enough. I've seen solar and batteries configured in ways that effectively worked against each other, costing the client money every single day. And I've seen businesses discover problems only after an expensive electricity bill landed on the desk.

So don't just ask "is my solar working?" Ask "how quickly would I know if it stopped?" Because the most expensive solar fault isn't necessarily the biggest fault. It's the one nobody notices.

Not sure whether your commercial solar is working? Send us a recent electricity bill, a photograph of your solar generation meter, and screenshots from your monitoring portal. From there, we can help establish what your system appears to be doing and what the sensible next step should be — whether that's an independent solar health check, help restoring your monitoring, or a bespoke monitoring strategy across multiple commercial sites.

Independent Solar Consultants Independent advice. Independent investigation. Evidence before assumptions.

Justin Dring is a commissioning design engineer and founder of Independent Solar Consultants, advising investors, asset managers and energy leaders on commercial solar, battery storage and data centre energy strategy. His work spans grid connection feasibility, BESS revenue modelling and independent technical due diligence — engineer-led and vendor-neutral, built for organisations committing serious capital who want the evidence in place before the decision, not after.