LONGi Solar performance guide

LONGi is the world's largest monocrystalline silicon manufacturer and consistently ranks among the top 3 panel producers globally. Their Hi-MO series panels have strong independent test performance and are widely deployed in Europe and Australia with a solid track record.

Hi-MO (High Efficiency Module) is LONGi's product line designation. The Hi-MO 6 series uses HPBC (Hybrid Passivated Back Contact) cells for 23%+ efficiency. Older Hi-MO 4 and 5 series used standard PERC and half-cut cell configurations, which are still reliable but less efficient.

LONGi offers a 25-year linear performance warranty and their panels are rated for 25–30 years. The Hi-MO 6 series is warranted to 0.4% maximum annual degradation — well below the 0.55% industry standard — and the Hi-MO 5 series to 0.45%.

PID (Potential Induced Degradation) is a failure mode caused by voltage stress between the panel cells and the aluminium frame, often accelerated by humidity and saltwater. LONGi's newer Hi-MO 5 and 6 panels have improved PID resistance. Older Hi-MO 4 panels on coastal sites are more susceptible and worth monitoring.

Yes. LONGi is a market leader in both countries. Their newer panels handle the UK's wet climate well and Australian heat competently. The temperature coefficient of -0.32% per °C (Hi-MO 6) is better than the -0.35% PERC industry standard.

Shading and soiling are the most common causes for systems under 10 years old. If the whole system's output is declining gradually (not just individual panels), check the inverter — LONGi panels rarely fail in the first decade under normal conditions.