A solar inverter converts the direct current (DC) electricity from your panels into alternating current (AC) used by your home and the grid. Common types include string, micro and hybrid inverters, with the best option depending on your system design, shading, battery plans and budget. Warning lights, error messages, unusual noise or a sudden drop in solar production may indicate a problem, but monitoring data can also reveal faults. Have a licensed electrician or qualified solar professional diagnose the issue, as replacement timing and costs depend on the inverter, installation and warranty.