What maintenance is required for solar electric systems?
If you own a home or a car or even a bicycle you know that it requires ongoing care to ensure its continued smooth and safe operation. A solar energy system is no different. In this article we’ll explore some sources of maintenance requirements, specific effects you may encounter, resulting symptoms, and how to best keep your system operating well.
Generally speaking, a solar energy system is very simple. At its heart, there are no moving parts. This is a major factor in keeping operating and maintenance costs low. A well designed system that is professionally installed will have very little need for ongoing maintenance. That said, no system is immune from wear and tear and there are a variety of unpredictable factors that could negatively affect your system performance and safety. There are also some special cases, including trackers and certain kinds of batteries, where routine active maintenance is critical to long term performance.
Sources of wear and tear
- Weather – wind, snow, ice, hail, rain, lightening, sun – these things all take a toll. Equipment and installations are designed for outdoor exposure and should last many years without incident, but weather impacts are impossible to predict and, as we are seeing, weather is becoming more and more extreme.
- UV degradation – many materials degrade in the presence of UV (ultraviolet) light, especially plastics. The severity of the degradation will depend on the quality of the product and the severity of UV exposure.
- Heat – the main enemy of electronics is heat. Electronics installed in the direct sun will experience more lifetime heating than those installed in a shaded area, and could experience a shorter lifespan or degraded performance as a result.
- Pests, plants, and insects can all have an impact from squirrel-chewed wires to growing plants casting shade on solar panels.
- Thermal cycling – Here in Canada we experience extreme swings in ambient temperature, from -30C to +30C or more. Electrical devices experience self-heating, pushing the swing even higher. All materials shrink and expand with temperature changes. This means they *move* and the greater the temperature change the greater the movement. Over time that movement can results in a variety of negative effects.
- Vandalism is not common, but can occur. Rocks and golf balls can find their way to solar panels, breaking the glass. Or accessible equipment can be tampered with.
- Product failures — though rare, inverters, solar modules, breakers, switches, and system accessories can fail.
- Poor installation can lead to all manner of problems including roof leaks, poor performance, and safety hazards.
Resulting effects on equipment
The sources above can result in negative effects, some safety related. Sometimes the cause is clear, sometimes not. Some of the more common effects are:
- Movement of wires or equipment
- Damage to wires from sharp or abrasive surfaces or from chronic wear and movement
- Cracking, splitting, disintegration of plastic or rubber parts
- Chewing of wires by pests, nesting in accessible cavities
- Ingress of water or insects into enclosures
- Corrosion of electrical or mechanical parts
- Loose electrical or mechanical connections
- Degradation or damage from chronic overheating
The solar array, consisting of solar modules (or panels), racking, wiring, and sometimes additional equipment is heavily exposed to weather. This is where we see movement of equipment, wires come loose from their containment, UV degradation, failed connectors, ingress of water into enclosures, failed roof attachment points or flashings, etc.
Inverter and other electronics
Inverters are electronic devices and generally have a 20+ year design life. In a well designed and installed system the inverter should just keep on working. We do see a few issues, though, including product failures and sometimes weather ingress.
Balance of System
‘Balance of system’ includes all the cable, conduit, switches, breakers, fuses, and other general parts that connect everything together. Dominant issues here relate to poor installation, thermal cycling, and ingress.
Batteries are a special case and are covered in depth in other articles. To summarize: flooded lead acid (FLA) batteries do require routine maintenance. Other battery types should undergo period inspection (more on this below).
Trackers are machines that physically turn a solar array to keep the solar modules always facing the sun for maximum energy generation. Trackers can increase the output from a given solar array considerably, but they do come with 2 major costs: installation cost is much higher than for a fixed mount, and moving parts! The moving parts, controllers, and sensors of a tracker make it the most complicated part in a solar energy system. The moving parts absolutely require periodic routine maintenance to inspect for wear and tear and ensure adequate lubrication.
Role of monitoring
Nearly all solar inverters have a system of online monitoring that will allow you to view current and historical performance and status. They can also dispatch an email to you if an error condition is encountered. These monitoring systems can be an important early warning system for needed maintenance. They can tell you if your system, or a part of it, is under-performing, if there are error codes or less severe warnings in need of attention, allow you to compare current performance to past performance, examine impact of shade, etc. The data available from the monitoring sysetm is more rich and detailed that what is available from the inverter front panel.
Typical Product Warranties
Warranties are covered in detail in another article, but here’s a quick summary:
- PV modules – usually 5 or 10 year workmanship warranty and 20 year performance warranty;
- PV racking – 10 years workmanship
- Inverters – 10 years, extendible to 15 or 20 at a cost
- Balance of System – 1 year
- Accessories – this includes communications devices and other secondary equipment – 1 year
- Batteries – 1 to 4 years, depending on the battery
Symptoms you may experience
The following symptoms indicate you are overdue for maintenance!
- Tripped breakers or blown fuses
- Inverter error codes
- Signs of nesting in or around your equipment or under your array
What can you do?
The most important thing you can do is catch small problems before they turn into big problems. Do this by taking advantage of your monitoring system and conducting your own periodic visual inspections. Look at the outside of the inverter and all the balance of system equipment; look for signs of movement, degradation, ingress, pests, and damage. If needed, use binoculars to inspect a roof mounted solar array. All the lines should be square and straight, there should be no wires hanging down below the racking, and all wiring leaving the array should be attached well supported and free of damage or degradation. Do this visual inspection a couple times each year.
Lastly, hire a qualified solar contractor to conduct a detailed preventative maintenance inspection annually or bi-annually. A detailed inspection will include:
- A visual and mechanical inspection of the solar array including roof attachment points, torque checks, wiring inspection
- An electrical inspection to confirm that all the strings of your solar array are operating
- Interior inspection of all devices, boxes, inverters, switches, etc.
- Battery maintenance and/or detailed inspection, if applicable
- Infrared inspection of electrical connections looking for loose connections and hot spots
- A detailed report with the results and any recommended actions.
A well designed and professionally installed system will resist most of what Mother Nature throws at it and perform well for many years. To help ensure that happens, have a preventative maintenance routine of performance monitoring, visual inspections, and professional preventative maintenance inspections.