Solar Panel Repair: Signs Your System Needs Service

A solar system that is working properly makes about the same amount of electricity year after year, with only a slow, expected decline. If your production drops suddenly, your inverter shows an error, or your electric bill jumps without explanation, something needs attention. This guide explains what is normal, what usually fails, and when to call a professional.

What normal decline looks like

Solar panels lose a little output every year. In an NREL analysis of nearly 2,000 measured degradation rates, the median was about 0.5% per year. The Department of Energy uses the same figure, saying module efficiency “unavoidably degrades at about 0.5% per year.” A gradual, small drop is normal. A sharp drop from one month to the next is not.

Signs your system needs service

Your monitoring app or production meter shows a sudden drop compared with the same time last year.
The inverter displays an error message or a warning light, or the system has stopped producing entirely.
Panels have visible cracks, discoloration, burn marks or moisture under the glass.
Your electric bill rises without a change in how you use power.
Wiring, connectors or mounting hardware look loose, damaged or chewed by animals.

The Department of Energy’s guidance for system operators is to regularly check production meters and “error messages on inverter faceplate,” and to have an electrical inspection done for ground faults when the system trips off.

What usually fails

The inverter is the most common weak point. DOE states that “the majority of downtime and maintenance is associated with inverters,” and a DOE article on solar power electronics notes their typical lifetime is only about 10 years, requiring replacement long before the panels do.

NREL’s list of common failure modes for crystalline silicon modules includes:

Broken cells and broken interconnects
Hot spots and bypass diode failures
Junction box and connection failures
Corrosion and delamination of the layers that protect the cells
Broken glass and ground faults

DOE adds that repairs commonly involve hot spots, cell cracks and water getting into the junction box. Storm damage is another cause; see our guide to what to do after hail damages your solar panels.

Do not repair it yourself

Solar wiring carries dangerous voltage, and the work is on a roof. Do not open junction boxes or replace connectors yourself, and do not climb on the roof to check panels. A qualified technician can test the electrical system, find the fault and tell you whether it is covered by a manufacturer or workmanship warranty.

When to call us

Oklahoma Solar Solutions diagnoses and repairs residential and commercial solar systems. Start with solar panel repair, a system inspection or ongoing solar system maintenance, or request a free estimate.