How your inherited solar system works — a plain-English guide
You have just bought a house with solar panels and a battery. You have a monitoring app you have never opened, a display you do not understand, and some questions. This guide explains what everything does and what the numbers mean.
By the end of this guide, you will know:
The basics: panels → inverter → home → grid
Here is how your solar system works in four simple steps. All of this happens in real-time, and your monitoring system shows each flow as it happens, measured in watts (W) or kilowatts (kW).
1. Solar panels generate DC power
When sunlight hits the panels on your roof, they generate direct current (DC) electricity. The amount varies with the intensity and angle of the sun. A sunny midday summer day produces far more than an overcast winter morning.
2. The inverter converts DC to AC
Your house needs alternating current (AC) electricity — the type that comes from the grid. The inverter sits between the solar panels and your home's electrics, converting the DC power to AC. This is why the inverter often has the most information on its display.
3. Your home uses what it needs
As solar power is generated, your home consumes what it can (lighting, heating, appliances, etc.). In summer or during a sunny day, you might produce much more than you use. This surplus goes either to the battery (if you have one) or out to the grid.
4. Surplus is stored or exported
If you have a battery, surplus solar energy is stored for use when the sun is not shining (evening, night, cloudy days). If you do not have a battery, or the battery is full, surplus power is exported to the grid — and you get paid for it via the Smart Export Guarantee.
What happens to excess electricity
Any solar electricity you export to the grid can earn money. This is called the Smart Export Guarantee (SEG) in the UK, and it is one of the main ways a solar system pays for itself over time.
How the Smart Export Guarantee works
When you export electricity to the grid (because your system produces more than your home uses), your energy supplier pays you for it. The rate is typically between 3p and 15p per kilowatt-hour (kWh), depending on your supplier and tariff. The previous owner registered a SEG tariff with their supplier. You need to transfer this to your name and bank account.
Three steps to claim your SEG payments
Most SEG contracts are registered to a specific person and bank account. Payments are likely still going to the previous owner's account.
Early action matters
SEG contracts may have expiry dates. If the previous owner's tariff expires and you have not claimed it, you lose that income. We recommend acting within the first month of purchase. See our full export guide for more details.
If you have a battery
A hybrid inverter with a battery gives you much more control over your solar energy. Instead of immediately exporting surplus to the grid, you can store it and use it when you need it most.
Daytime (sunny): Solar → Battery → Home
During the day, excess solar power charges the battery first. As the battery charges (and when it is full), any remaining surplus is exported to the grid. Your home draws from both solar and the battery as needed.
Evening / Night: Battery → Home
When the sun sets and panels stop generating, your home draws power from the battery. The battery discharges until either it is empty or you have reached your programmed minimum State of Charge (SoC) limit.
Late night: Grid → Home (or Battery charge schedule)
If the battery is fully discharged and you still need power, your home draws from the grid. Some systems are configured to automatically charge the battery from the grid at off-peak times (usually 23:30–05:30 on Economy 7 tariffs) to take advantage of cheaper rates.
Configuration issues: where problems usually hide
Most issues with hybrid systems come from three common places:
1. Battery charge schedule
The previous owner may have set the battery to charge from the grid at specific times (e.g., off-peak hours). If the schedule is wrong, the battery might charge at the wrong time or not charge at all. Check your inverter's settings menu or monitoring app for 'Charge Schedule', 'Battery Settings', or 'Tariff'.
2. State of Charge (SoC) limits
The battery may be set to never go below a certain percentage (e.g., 20%) or above a certain percentage (e.g., 95%) to prolong its life. This can look like the battery has stopped charging. Verify these settings in your monitoring app.
3. Tariff time settings
Economy 7 or other time-of-use tariffs require correct clock settings on the inverter. If the time is wrong, the battery will charge and discharge at the wrong times. Check your inverter's date and time settings.
What your monitoring system shows
Your solar system's monitoring app or display is your window into what is happening in real-time. Learning to read it tells you whether your system is working correctly and what it is earning.
Real-time metrics (today, right now)
Generation / PV Power
How much power your panels are producing at this moment, measured in watts (W) or kilowatts (kW). Sunny day midday: 5–10+ kW. Cloudy day: a few hundred watts. After sunset: 0W. This is normal.
Battery State of Charge (SoC)
The percentage of energy in the battery right now, from 0% (empty) to 100% (full). On a sunny day, this should slowly increase. At night or on very cloudy days, it should decrease as you use the stored energy.
Home Load / Consumption
How much power your house is using at this moment (all appliances, heating, lighting, etc.). Overnight or quiet daytime: 0.2–1 kW. Busy daytime with appliances: 2–5+ kW. Heating on: can jump to 3–10+ kW.
Grid Power (Import / Export)
Power being pulled from the grid (import) or sent to the grid (export). Shown as positive (import) or negative (export). Positive numbers mean pulling from grid. Negative numbers mean sending to grid and earning SEG payment.
Daily and historical data
Daily Generation
Total kWh generated today. Summer days might show 25–40+ kWh. Winter days show 5–10 kWh. Cloudy days show less.
Daily Export
Total kWh exported to the grid today. This is what earns you SEG payments. Usually a portion of daily generation if you are not using it all.
Historical performance charts
Graphs of generation, consumption, battery charge/discharge over days, weeks, months. These show trends and help spot issues (e.g., sudden drops in generation or battery not charging on sunny days).
Common things that confuse new owners
Why is it showing zero generation on a cloudy day?
This is completely normal. Solar panels only generate when sunlight is available. On heavily cloudy or overcast days, generation may drop to zero or a few hundred watts. This is not a fault. If you see zero generation on a clear sunny day between 9am and 4pm, something may be wrong.
The battery is not charging even though the sun is shining
Check three things: (1) Is there enough surplus solar generation after your home's consumption? If you are using most of what the panels generate, there is nothing left to store. (2) Is the battery SoC limit set too high (e.g., only charges to 80%)? (3) Is the charge schedule configured correctly in your inverter settings? Most often it is a settings issue. A remote diagnostic can confirm.
Why does generation change so much throughout the day?
This is perfectly normal. Solar generation depends on sun angle, cloud cover, and shadows. Generation is highest at midday (when the sun is highest), lower in the morning and evening, and zero after sunset. On sunny days, generation typically follows a smooth curve peaking around noon.
The battery is discharging even though the solar is generating
Your home's consumption may be higher than the solar generation at that moment. The system prioritizes powering your home, so it pulls from the battery first (because it is available), then from solar, then from the grid. This is normal behavior. You will see the battery charge when solar generation exceeds home consumption.
The monitoring app shows different numbers to the inverter display
This usually happens if there is a time sync issue between devices, or if one is updating faster than the other. Both should match if you wait a few seconds. If they differ significantly (e.g., generation is 5kW on the app but 0kW on the display), there may be a communication error. Try restarting the inverter.
When to call a professional
Some issues are beyond troubleshooting and need specialist help. This is important for your safety, your warranty, and protecting your investment.
Book a remote diagnostic if:
Book a site visit (electrician) if:
You should not attempt these yourself. They require a qualified electrician:
Some settings are locked by the inverter manufacturer for safety or warranty reasons. Others require specialist knowledge to change correctly. If you adjust charge schedules or SoC limits incorrectly, you could damage the battery, void the warranty, or stop the system from exporting to the grid. We recommend getting specialist help before making changes.
Related guides
This guide is part of our Bought a House With Solar hub. Explore related topics:
Check your export payments
How to transfer your SEG tariff and make sure you are receiving payment for exported electricity.
Lost monitoring access?
What to do if you cannot log into your monitoring app or portal after inheriting the system.
Identify your inverter
How to find your inverter model, serial number, and brand from the device or paperwork.
Solar Health Plan
Annual maintenance and monitoring plan to keep your system running at peak efficiency.
Available on-site across Yorkshire & beyond
If you need hands-on help understanding your inherited solar system, we offer on-site walk-throughs across our full coverage area — from Leeds and Bradford to York, Sheffield, Hull, and beyond.
See all areas we cover →Frequently asked questions
Something on your system not behaving as expected?
If something doesn't match what this guide describes — error codes, no generation, odd readings — a remote diagnostic is the fastest way to a clear answer. Fault identified within 30 minutes. Health check from £145.