Before You Blame the Inverter, Check the Panels First
When production drops, most homeowners assume there is an electrical fault or a failing inverter. In the Axarquía, the culprit is often much simpler—and much cheaper to fix.
It is a frustrating moment: You open your solar monitoring app (FusionSolar, Victron, Fronius, etc.) and notice that even though it is a beautiful cloudless day in Málaga, your system is producing 20% less power than it did this time last year.
Your first instinct might be to call your installer and report a faulty inverter. But before you pay for a technical house call—which can be expensive and often unnecessary—you should perform some simple visual and performance checks. At Axar Solar Clean, we find that the vast majority of "underperforming" systems are simply suffering from environmental factors.
Important Disclaimer:
We are cleaning and maintenance specialists, not electricians. If your inverter shows a red light, a specific "Earth Fault," or if you see exposed wiring, stop immediately and call a certified solar installer. Never touch electrical components or attempt to open the inverter or DC isolators.
The "Production Drop" Checklist
Before assuming an equipment failure, work through these three practical checks.
1. Seasonal sun angles
The sun is much lower in January than in July. Check if a nearby tree, chimney, or your neighbor's new pergola is casting a shadow that didn't exist in the summer. Even a shadow on just 10% of a panel can shut down the production of that entire string.
2. Heat-related clipping
Solar panels actually like cold, sunny days better than hot ones. On a 35°C August day in the Axarquía, your panels might produce 15-20% less power simply because they are over-heating. Efficiency drops by about 0.3% for every degree above 25°C.
3. The "Soiling" Check
Does the glass look grey, orange, or dull from the ground? Saharan dust and pollen create a "filter" over your panels. This is the most common cause of gradual production decline in southern Spain.
The "Hot Spot" Warning
Bird droppings are more than just an eyesore. They create "hard shading." If a single dropping covers a few cells, it creates resistance in the circuit. The inverter sees the whole string underperforming because of that one spot. Over time, that resistance creates heat, which can lead to a hot spot that permanently damages the solar cell.
A simple professional clean can prevent this permanent hardware damage.
The 10% Rule
If your production is 5-15% lower than expected, it is almost certainly dust, pollen, or heat. If your production has dropped by 50% or more, or if one specific "string" (group of panels) is showing zero volts while others are fine, that indicates a potential blown fuse, a localized shading issue, or a hardware failure.
Cleaning as a Diagnostic Tool
We often recommend owners clean their panels as the first step in diagnosing a perceived fault. It is the cheapest variable to eliminate.
- Before cleaning: Take a screenshot of your peak power (kW) at midday.
- After cleaning: Check the peak power at midday on the next clear day.
If your production returns to normal, you've saved yourself the cost of an electrician's call-out fee and confirmed that your hardware is healthy.
Production still low?
Start with a professional clean. We will also perform a visual inspection of your panels to check for cracks, loose wires, or visible damage while we are on the roof.