Guide to Solar PV Maintenance
Solar PV systems were often sold as "fit and forget", but in reality one should be considering getting the system checked out after it has been on the roof for a few years, even if you think it is performing well and installed properly. Ground mounted systems can be even more susceptible to damage from lawnmowers, strimmers, rodents, grazing animals and plants.
There a several factors which can have an impact on solar system performance, our short guide should help you understand the fundamentals...
All electrical systems degrade over time - it's unavoidable. UV radiation, moisture, poorly made off wiring connections, inadequate wiring support and wind damage can all take their toll. Eventually this can lead to current leakage and ultimately a risk of electric shock or increased fire risk. Whilst many installations will last for years without any serious problems, checking the system regularly can go along way to reducing risk before accidents or damage occurs. Sometimes cables might have been installed in areas which were not appropriate - such as near heating pipes or ducts where higher temperatures are normal - or where there is a greater risk of abrasion or mechanical damage from rodents or livestock.
When the panels are connected to the inverter they should be arranged in such a way as to conform to the manufacturer's design criteria. This means the panels will be producing energy within the inverter's design voltage and current range. If the panel layout was incorrectly designed or installed this can lead to very poor performance. It could even lead to less than half the available power being utilised by the inverter.
Some examples may illustrate the point:
1: Panels where some of the array is pointing in a different direction to another part of the array require separate inverter inputs for each part. This can be overlooked by poorly trained installers, leading to significant performance reduction
2: Too many panels for the inverter can lead to significant trimming of the output power and could even mean the inverter is electrically overloaded and unsafe - this may also lead to discovery of other components such as switchgear not being properly specified.
3: If an incorrect inverter was chosen for the given orientation of the panels.
4. Part of the array is in shade, having a negative impact that affects the whole array. This can be remedied by either changing the inverter configuration or the inverter itself (or upgrading the panels with optimisers, though this can be an expensive option)
Poor electrical design
Poor wiring design can occasionally lead to interference with wifi and television equipment. Incorrectly specified switch gear or cabling can lead to fires and electrocution risk if they are overloaded or not rated for the job in hand. Unfortunately there are many systems out there where inappropriate equipment has been chosen or the wiring has been done badly.
Cheap or faulty equipment
Most inverters have 5 year warranties, and whilst good quality ones are expected to last well in excess of this period, some cheaper low cost models which were commonly being brought in 3 or 4 years ago will just not last much past this point. You will notice complete failure when your generation meter readings stop increasing, but we may be able to help you identify faults before this happens.
Solar panels often perform well above their rated output at the beginning of their lifespan, and continue to do so for many years. MCS approved panels will have performance warranties which guarantee outputs - usually for a standard 10 or 12 years at 90% and then another 10 years at 80% or more. It is very difficult for the layperson to ascertain whether this performance is actually being met. We can help by showing you what performance should have been expected based on your location, the orientation of the panels using information you have to hand. We can also use specialist equipment to track down individual faulty panels.
Your legal obligations
All electrical installations should be regularly inspected for safety - this applies to houses as well as businesses. There are recommended periods for inspection in the electrical regulation guidance notes, and some properties have more rigorous guidance set down, such as hospitals and schools. However PV systems are a grey area, and the recommended period between inspections is not set down anywhere at this time. Ultimately we would recommend an inspection on houses no later than 5 years after installation. Other more aggressive environments such as poultry farms should be inspected far more regularly...
You can use our handy performance prediction spreadsheet to see what your system should have been producing...
Just drop us an email and we'll send it over
DOMESTIC and COMMERCIAL SERVICES
We can offer one performance testing as either a one off or regular service, using state of the art "IV" tracing equipment.
We use a Seaward dedicated PV analysis tester which allows us to show how the panels are performing compared to the manufacturers predictions - it also helps to track down faults such as dangerous wiring, panel degradation and other specific problems.
If you'd like assstance on tracking down faults then please get in contact, or if you would like more information on maintaining PV systems in good condition then you can read more on our PV Maintenance information page.
Other tests which can be performed include continuity of earth path, insulation resistance, check for correct selection of protective devices, functional checks of switchgear and ensure adequate shutdown procedures plus labelling are in place
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