You installed solar to keep the lights on during load-shedding. Now you may be using it to lower your electricity bill instead. After four years of use—covering 2023, 2024, 2025 and 2026—it’s natural to wonder: is the system still working as it should, and is there anything I need to do? If your system has eight solar panels, an 8 kVA inverter and a 10 kWh battery, you don’t need to become an energy expert to check on it. A few simple observations can tell you when everything looks normal—and when it’s time to call your installer.
What do the numbers mean?
The panels make electricity from sunlight. The inverter changes that electricity into a form your home can use. The battery stores some of it for later. The inverter’s 8 kVA rating describes how much power it can supply at once. The battery’s 10 kWh rating describes how much energy it can store. The battery may not deliver all 10 kWh to your home: the system usually keeps some in reserve and loses a little energy when converting power.
Your panels should still be producing well
Solar panels gradually lose a small amount of output as they age. Research by the US National Renewable Energy Laboratory suggests a typical loss of around 0.5% to 0.75% a year. After four years, that would leave panels producing roughly 97% to 98% of their original output, before accounting for dirt, shade or a fault. Results vary between systems. NREL’s degradation review and PV fleet analysis provide useful benchmarks. Dirt on the panels, new tree shade or a fault can reduce production more than normal ageing. If you use a monitoring app, compare production across similar months or seasons. Cloudy weather and shorter winter days naturally mean less generation. If production seems much lower than before, ask your installer to investigate.
How much life is left in the battery?
Battery capacity reduces over time, but there is no single figure that applies to every home. The result depends on the battery type, temperature, settings and how much it has been charged and discharged. A short power cut is not the same as using nearly all of the battery’s stored energy. If yours is a lithium iron phosphate (LFP) battery and has been well looked after, around 80% to 90% of its original usable energy after four years is a reasonable planning estimate—not a guarantee. Check the warranty for your exact model, as manufacturers use different limits and test conditions.
A battery labelled 10 kWh may not have delivered all 10 kWh to your home when it was new. Reserve settings and conversion losses reduce the energy your appliances receive. As a rough illustration, a battery retaining 80% to 90% of its original capacity, with 80% available for use, might provide around 6.4 to 7.2 kWh before conversion losses. Your system’s actual settings may differ. You don’t need to run the battery flat to check it. Notice whether it still powers your usual evening essentials for about as long as before. If it runs down much faster, switches off early or shows repeated warnings, ask your installer to measure its capacity and check the warranty.
A few simple things you can do
- Check your app occasionally. Look for panel production, battery charging and discharging, and warning messages.
- Keep an eye on the panels. Heavy dirt or new shade can reduce production. Follow the manufacturer’s cleaning instructions, or arrange help if the roof is difficult to access.
- Keep the inverter area clear. It needs space and airflow. Don’t open it or touch its wiring.
- Ask for a professional check if something changes. An installer can safely inspect the wiring, protective equipment, inverter ventilation and battery connection.
- Keep your paperwork. Installation date, equipment details, warranties and electrical safety documents will help if you need support.
From backup power to lower bills
Your system may have been bought for peace of mind during power cuts. It can also help reduce the electricity you buy from the grid. Where practical, run flexible appliances—such as the washing machine or pool pump—while the sun is shining. Ask your installer whether a geyser timer or controller can use spare solar power to heat water during the day. The best settings depend on your household and tariff. Fixed charges may still appear on your bill, and tariffs vary between Eskom and municipalities, so check your own bill when working out your savings. Eskom’s retail tariff information
The reassuring news: after four years, a well-installed system should still have plenty of useful life. Keep an eye on whether the panels are producing, whether the battery lasts as expected, and whether the app shows warnings. If something changes noticeably, ask a qualified installer to check it.
LWP Properties
Beyond the Sale
