LONGi Hi-MO 7 590W Specifications & Review

The 590W and 620W versions use identical HPBC cell technology and achieve the same 22.8% efficiency. The difference is panel size: the 590W uses a 2278×1134mm frame (60 cells) while the 620W uses 2384×1134mm (66 cells). The 590W is lighter (28.8 kg vs 31 kg) and better suited for residential rooftops. The 620W produces more power per panel but requires heavier-duty racking.

Potentially yes. Front-side solder joints between busbars and cells are a common failure mode in conventional panels — they can crack from thermal cycling, causing hot spots and power loss. HPBC eliminates these front joints entirely, moving all connections to the rear where they're protected from UV and weather. While HPBC is a newer technology with less field history, the theoretical reliability advantages are significant.

Both use back-contact cell architectures — LONGi's HPBC and SunPower's IBC (Interdigitated Back Contact). The Hi-MO 7 at 590W/22.8% is competitive with SunPower Maxeon 6 (415W/22.8%). The key differences: Hi-MO 7 has higher per-panel wattage but is larger; Maxeon has a 40-year warranty vs LONGi's 12/30-year; LONGi is lower-priced per watt. Both offer premium aesthetics and reliability.

The standard Hi-MO 7 590W uses a glass-backsheet construction with tempered glass front and polymer backsheet rear. LONGi may offer glass-glass variants for specific markets. The glass-backsheet version is lighter and more common for residential rooftop installations.

LONGi Hi-MO 7 panels are available through major US distributors (CED Greentech, BayWa r.e., Soligent) and are stocked by many local and regional installers. National installers like SunPower, Sunrun, and Tesla typically use their own panel brands, but independent installers commonly offer LONGi. Request the Hi-MO 7 specifically — some distributors may default to the older Hi-MO 6 series.

The Hi-MO 7 uses 3 bypass diodes, so shading one-third of the panel reduces output by approximately one-third rather than disabling the entire panel. HPBC's back-contact design does not inherently improve shade tolerance. For roofs with partial shading (trees, dormers, vents), pair the Hi-MO 7 with microinverters or SolarEdge optimizers for panel-level MPPT that minimizes shading losses across the system.

Both HPBC and HJT are next-generation cell technologies beyond TOPCon. HJT (used by Risen, REC) achieves the best temperature coefficients (-0.25%/°C) through amorphous silicon heterostructures. HPBC (LONGi exclusive) achieves comparable efficiency through back-contact design that eliminates busbar shading. HJT is better in extreme heat; HPBC is better in low light. Both offer premium performance above standard TOPCon.

LONGi is the world's largest solar company by manufacturing capacity, producing everything from silicon ingots to finished modules. They pioneered the mono PERC revolution that dominated 2018-2023 and are now leading the transition to HPBC as their next-generation platform. LONGi is Bloomberg Tier 1 bankable and trades on the Shanghai Stock Exchange with a market cap exceeding $30 billion.

The LONGi Hi-MO 7 590W achieves 22.8% module efficiency using HPBC (Back Contact N-type) cell technology. This is above the industry average for residential solar panels in 2026.

It comes with a 12-year product warranty and a 30-year performance warranty guaranteeing output at approximately 87.4% of rated power at the end of the warranty period.

With a temperature coefficient of -0.28%/°C, the Hi-MO 7 590W handles heat well with minimal power loss. Every degree above 25°C reduces output by 0.28%.

At 590W per panel, you would need approximately 14 panels for an 8 kW system or 17 panels for a 10 kW system. Each panel measures 2278 x 1134 mm (27.8 sq ft).

The LONGi Hi-MO 7 590W works well with both string inverters and microinverters. For string inverters, choose one with a maximum input voltage above 52V and an MPPT voltage range that covers 44V. Microinverters rated for 590W+ panels are also an excellent choice, offering panel-level monitoring and shade tolerance. Popular options include Enphase IQ8 series microinverters and SolarEdge string inverters with power optimizers.

The LONGi Hi-MO 7 590W is built to last well beyond its 30-year performance warranty. With first-year degradation of 1% and annual degradation of 0.4% thereafter, the panel will still produce approximately 87.4% of its rated power after 30 years. Most modern solar panels continue generating useful power for 30-40 years, though output gradually decreases over time.

Yes, the LONGi Hi-MO 7 590W is an excellent choice for hot, sunny states like Arizona, Nevada, and Texas. Its temperature coefficient of -0.28%/°C is better than the industry average of -0.35%/°C, meaning it retains more power output on hot days. Higher sun exposure in these states means more total energy production throughout the year, often offsetting any heat-related losses.

The LONGi Hi-MO 7 590W delivers 22.8% efficiency, which is above the industry average of ~21%. Combined with a standard 12-year product warranty and 30-year performance guarantee, it offers strong value for homeowners seeking reliable solar generation.