{"id":2328,"date":"2026-10-06T09:56:00","date_gmt":"2026-10-06T06:56:00","guid":{"rendered":"https:\/\/mits.sa\/%d8%a3%d8%b9%d8%b7%d8%a7%d9%84-%d8%a7%d9%84%d9%85%d9%86%d8%b8%d9%88%d9%85%d8%a9-%d8%a7%d9%84%d8%b4%d9%85%d8%b3%d9%8a%d8%a9\/"},"modified":"2026-10-17T08:30:05","modified_gmt":"2026-10-17T05:30:05","slug":"solar-system-faults","status":"publish","type":"post","link":"https:\/\/mits.sa\/en\/solar-system-faults\/","title":{"rendered":"Common solar system malfunctions and how to detect them"},"content":{"rendered":"<p>Common solar panel malfunctions often manifest in one of three ways: zero output, less than usual output, or a warning message on the inverter screen. Most of these malfunctions can be identified through observation and by reviewing the monitoring application, but the repair itself requires a qualified technician because the DC voltage in the panels is dangerous.<\/p>\n<div class=\"mits-box\"><strong>In short:<\/strong><\/p>\n<ul>\n<li>Always start with the inverter application: daily production, alarm messages, and comparing the chains with each other.<\/li>\n<li>A near halving of production could mean the shutdown of an entire series of panels, not just dust.<\/li>\n<li>The grid-connected system automatically shuts down when the power goes out; this is a safety design, not a malfunction.<\/li>\n<li>Do not open the connection boxes or the inverter yourself, and insulate the system before approaching any cable.<\/li>\n<\/ul>\n<\/div>\n<h2>First step: Read what the system says<\/h2>\n<p>Modern inverters record production in real time and daily, and display warning messages with codes and descriptions. Before assuming any cause, consider three things:<\/p>\n<ol>\n<li><strong>Daily production compared to similar sunny days<\/strong>Is the decrease sudden or gradual?<\/li>\n<li><strong>Warning messages and their timing<\/strong>Does it appear only in the morning? Or at noon? Or after rain or washing?<\/li>\n<li><strong>Performance of each series<\/strong> If the inverter displays input data separately.<\/li>\n<\/ol>\n<p>Write down the alarm code exactly as it appears, and take a picture of the screen. This information alone will save the technician a great deal of time in diagnosis and help them refer to the manufacturer&#039;s manual.<\/p>\n<h2>Quick diagnostic chart for common faults<\/h2>\n<table class=\"mits-t\">\n<thead>\n<tr>\n<th>the offer<\/th>\n<th>Possible causes<\/th>\n<th>What do you do?<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Zero production on a sunny day<\/td>\n<td>Circuit breaker disconnected, DC switch off, network outage in a tethered system, inverter fault<\/td>\n<td>Check the circuit breakers and network status, then contact a technician if the problem persists.<\/td>\n<\/tr>\n<tr>\n<td>Gradual decrease in production<\/td>\n<td>Accumulated dust, a new shadow from a tree or building<\/td>\n<td>Clean the panels and observe the difference; examine the sources of shade.<\/td>\n<\/tr>\n<tr>\n<td>A sudden drop of almost half<\/td>\n<td>The entire series has stopped; a connector is disconnected or burned out; the series fuse has blown.<\/td>\n<td>Isolate the system and call a technician to examine the chain.<\/td>\n<\/tr>\n<tr>\n<td>Lowering the time at noon only<\/td>\n<td>High temperature, inverter reduces its power due to poor ventilation<\/td>\n<td>Check the location and ventilation of the inverter.<\/td>\n<\/tr>\n<tr>\n<td>Ground leak or insulation alarm<\/td>\n<td>Damaged cable, moisture inside connector or junction box<\/td>\n<td>Do not touch anything, and call a qualified technician.<\/td>\n<\/tr>\n<tr>\n<td>Frequent power outages at night (battery systems)<\/td>\n<td>Insufficient capacity, deteriorated battery, unsuitable charging settings<\/td>\n<td>Review nighttime loads and system settings with the technician.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>Zero production: Where do you start?<\/h2>\n<p>If the sun is shining and the output is zero, the problem is often with the protection or the grid, and not with the panels themselves.<\/p>\n<h3>In network-connected systems<\/h3>\n<p>A grid-tied inverter is designed to shut down immediately when the mains power goes out, preventing it from supplying electricity to lines being worked on by maintenance technicians. Therefore, if the power goes out in your neighborhood, your system will also shut down and will automatically restart once the grid is restored and stabilized. If you need power during outages, you need a hybrid system. The differences between these systems are explained in a separate article. <a href=\"\/en\/on-grid-vs-off-grid-vs-hybrid\/\">The difference between On-Grid, Off-Grid and hybrid systems<\/a>.<\/p>\n<p>The inverter may also stop if the network voltage or frequency is outside the allowed limits, and this will be indicated in a network-specific warning message.<\/p>\n<h3>Circuit breakers and disconnect switches<\/h3>\n<p>Check the circuit breakers on the system panel without opening it. If you find a breaker that is tripped, do not restart it repeatedly. A tripped breaker indicates that the protection system has detected something, and repeated restarts may be masking a serious problem.<\/p>\n<h2>Lower-than-usual production: How to differentiate between the reasons?<\/h2>\n<p>Here&#039;s where a simple calculation will help. Take, for example, a 10 kW system distributed across two equal 5 kW strings. One kilowatt produces approximately 5 kilowatt-hours per day on average, so the expected output is approximately 10 x 5 = 50 kilowatt-hours.<\/p>\n<ul>\n<li>If production becomes 46\u201347 kWh after two weeks without cleaning, this is a gradual decrease consistent with dust accumulation.<\/li>\n<li>If it suddenly drops to approximately 25 kilowatt-hours, i.e., 50 \u00f7 2, then the most likely scenario is that an entire chain has stopped.<\/li>\n<li>If the drop occurs only at noon in the summer, the cause may be the heat or the inverter reducing its power.<\/li>\n<\/ul>\n<p>Modern solar panels lose approximately \u22120.29% to \u22120.40% of their capacity for every degree above 25\u00b0C; this is normal and not a malfunction. Details are available in the article. <a href=\"\/en\/heat-effect-on-solar-panels\/\">The effect of heat on solar panel production<\/a>.<\/p>\n<div class=\"mits-tip\"><strong>\ud83d\udca1 Tip:<\/strong> Don&#039;t judge production based on a single day. Compare week to week under similar weather conditions. Clouds and dust storms temporarily reduce production, but the real disruption continues even after the weather clears and cleaning up.<\/div>\n<h2>Panel, cable, and connector faults<\/h2>\n<h3>Burnt connectors<\/h3>\n<p>One of the most common faults discovered during inspection is a conductor between two plates or at the end of a string that appears blackened or melted. Typical causes include improper installation, mixing incompatible conductors, or the introduction of moisture and dust. A loose conductor heats up as current flows and may form an electrical arc, potentially causing a fire.<\/p>\n<h3>Hot spots and cell damage<\/h3>\n<p>Continuous partial shading or microscopic cracks in the cells can cause hot spots. Signs include brown spots or discoloration of a portion of the board. A technician can confirm this with a thermal imaging camera during operation.<\/p>\n<h3>Insulation damage<\/h3>\n<p>Cables exposed to the sun without protection, or those rubbing against the edges of the enclosure, or those exposed to rodents on farms, may have their insulation damaged. This can result in an insulation or ground fault warning, and sometimes the inverter will shut down in the morning after dew and then resume operation once the air dries.<\/p>\n<h2>Inverter, battery, and submersible pump malfunctions<\/h2>\n<p>The inverter is the brain of the system, and many of its malfunctions manifest with clear warning signs. The most common are: overheating due to blocked ventilation openings or installation in direct sunlight, faulty power supply connections, and fan failure. If the inverter is close to 10\u201315 years old, replacement may be more advantageous than repair. When replacing it, choose a device that matches the power rating of the panels, the voltage of the power supply, and the type of system.<\/p>\n<p>In battery systems, the most common complaint is that the power goes out before morning. Possible reasons:<\/p>\n<ul>\n<li>Increasing nighttime loads beyond what the system was designed for, such as adding a new air conditioner.<\/li>\n<li>Battery capacity degrades with cycles, especially gel batteries that can withstand approximately 500\u20131500 cycles.<\/li>\n<li>The battery management system is disconnected for protection in case of low voltage or high temperature.<\/li>\n<li>Charging settings that are not suitable for the battery type.<\/li>\n<\/ul>\n<h3>Submersible pump system malfunctions<\/h3>\n<p>On farms, the problem typically manifests as a decrease in the water supply to the reservoir. Variable Speed Drives (VFDs) register faults such as dry running when the well level is low, high current when the pump is tired or the discharge is blocked, or low voltage due to poor radiation or dirty plates. Consult the fault log, and do not attempt to remove the pump or open the VFD without a qualified technician.<\/p>\n<h2>When should you call a technician and when should you fix it yourself?<\/h2>\n<p>What you can do yourself is limited and safe: monitor production, clean panels after insulation, check the condition of the circuit breakers from the outside, and remove sources of shade. Anything that requires opening a panel, touching a cable, or measuring voltage is qualified technical work.<\/p>\n<p>If you want to understand how technicians diagnose faults, the first level in <a href=\"\/en\/learn\/\">MITS Free Academy<\/a> It explains the basics in an interactive way. For a preventative checklist that avoids most of these problems, see the article. <a href=\"\/en\/solar-system-maintenance\/\">Solar system maintenance<\/a>. For organizations seeking a comprehensive assessment of an existing system, [the following is available]. <a href=\"\/en\/solar-energy\/engineering-consulting\/\">Engineering Consulting Service<\/a>You can review <a href=\"\/en\/solar-products\/\">Solar energy products<\/a> When replacement parts are needed.<\/p>\n<h2>Frequently Asked Questions<\/h2>\n<div class=\"mits-faq\">\n<h3>Why did my system stop working when the electricity went out, even though the sun was there?<\/h3>\n<p>Because grid-tied systems are designed to shut down during outages to protect network technicians, you need a hybrid system with batteries or backup power to provide electricity during an outage.<\/p>\n<h3>The inverter gives an alarm in the morning and then works normally. Is this dangerous?<\/h3>\n<p>This could indicate poor insulation, which becomes apparent with moisture and dew and then disappears after drying. Don&#039;t ignore it, as the problem often worsens over time. Request an insulation inspection from a qualified technician.<\/p>\n<h3>Is the decrease in production during the summer a disruption?<\/h3>\n<p>A decrease in efficiency at midday due to heat is normal. However, if the decrease is significant and sudden, or persists after cleaning, check the chain data and request an inspection.<\/p>\n<h3>How do I know if the problem is in one board?<\/h3>\n<p>A single damaged board reduces the production run of its series and may show visible signs. Confirmation requires measurements or thermal imaging by a qualified technician.<\/p>\n<h3>What is the natural output of my system?<\/h3>\n<p>Approximately 4.5 to 6 kilowatt-hours per day per kilowatt-hour, depending on the city and season. <a href=\"\/en\/solar-energy-calculator\/\">Solar Energy Calculator<\/a> To estimate your expected output and compare it to the actual output.<\/p>\n<\/div>\n<div class=\"mits-cta\">\n<p><strong>Do you need a suitable system?<\/strong> The MITS team designs and installs systems with correct protections and connections from scratch, and helps you diagnose faults in your existing system.<\/p>\n<p><a href=\"\/en\/contact\/\">Request a price quote<\/a> \u00b7 <a href=\"https:\/\/wa.me\/966575993880\">WhatsApp 0575993880<\/a> \u00b7 <a href=\"\/en\/solar-energy-calculator\/\">Try the calculator<\/a><\/p>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>Common solar power faults and how to detect them: zero or low output, insulation alarms, burnt connectors, inverter and battery problems with a quick diagnostic 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