Longi solar panels in Perth: what to know about the world's largest manufacturer

Longi Solar (now branded as LONGi Green Energy) is the world's largest solar panel manufacturer by shipment volume. Their Hi-MO series panels are widely specified by Perth solar installers, particularly in the value-to-quality tier. Here's what you need to know about choosing Longi for a Perth installation.

Who is LONGi?

LONGi (full name LONGi Green Energy Technology Co., Ltd) was founded in China in 2000 and listed on the Shanghai Stock Exchange in 2012. They pioneered high-efficiency monocrystalline silicon manufacturing at scale and drove industry-wide adoption of mono PERC technology. As of 2024–2025, LONGi is consistently ranked as the world's highest-volume solar panel manufacturer.

Their Australian operation (LONGi Solar Australia) supports warranty claims and technical support for the Australian market.

LONGi product lineup for Perth

The main LONGi series commonly specified in Perth:

Hi-MO 5 (LR5 series): Monocrystalline PERC in 400–450W range. The most common LONGi product in Perth residential installations. HALF-CUT cell technology (which reduces resistive losses and improves shade tolerance compared to full-cell modules).

Hi-MO 6 (LR6 series): Updated PERC with minor efficiency improvements. 420–470W. Increasingly common as the Hi-MO 5 phases out.

Hi-MO X6 (HIMO6 / Hi-MO X series): TOPCon technology — an advancement over PERC with slightly better efficiency and lower temperature coefficient. Represents the higher end of LONGi's residential range.

How LONGi panels perform in Perth's climate

Temperature coefficient: LONGi Hi-MO 5/6 PERC: approximately -0.35%/°C — typical for PERC technology, slightly below Q CELLS (-0.34%/°C) but the difference is negligible in practice. At 65°C cell temperature (Perth summer), both produce roughly 11% less than rated output.

LONGi Hi-MO X (TOPCon): Temperature coefficient approximately -0.30%/°C — slightly better than PERC, narrowing the gap with REC Alpha (-0.24%/°C) but not closing it.

Half-cut cell technology: LONGi's Hi-MO panels use half-cut cells. Half-cut cells have lower resistive losses and better shade performance — if one row of half cells is shaded, only half the panel is affected rather than the entire module (as in a full-cell string design). This is a meaningful benefit for Perth roofs where partial shading (from vents, antennae, or early-morning shadows) affects some panels.

Warranty

| Warranty element | LONGi Hi-MO 5/6 | |---|---| | Product/materials warranty | 12 years | | Performance warranty | 25 years | | Year-1 degradation | ≤2% | | Annual degradation (years 2–25) | ≤0.55% | | End-of-warranty output | ≥84.8% of rated power |

LONGi's 0.55%/year degradation rate is comparable to Q CELLS (0.54%/year) and significantly better than the industry baseline (0.7%/year). The 84.8% at year-25 guarantee is solid for PERC technology.

Warranty service in Australia: LONGi Australia handles warranty claims. Perth installers who regularly use LONGi panels report adequate warranty support, though LONGi's Australian footprint is smaller than their global market share might suggest. Confirming your installer's warranty claim pathway for LONGi is advisable.

Pricing

LONGi sits in the value Tier-1 segment — better than unbranded or generic modules, below premium brands like Q CELLS and REC Group.

Typical Perth pricing comparison for a 10kW system (after STC):

• LONGi Hi-MO 6 + Sungrow SG: approximately $9,000–$12,000
• Q CELLS Q.PEAK DUO + Sungrow SG: approximately $10,500–$14,000
• REC Alpha + Fronius GEN24: approximately $13,000–$18,000

LONGi is typically $1,000–$2,000 less than Q CELLS for an equivalent specification. This is the main reason they're frequently specified in cost-competitive Perth quotes.

LONGi vs Q CELLS vs generic Tier-1

| | LONGi Hi-MO | Q CELLS Q.PEAK DUO | Generic Tier-1 (Jinko/Trina) | |---|---|---|---| | Technology | PERC / TOPCon | PERC | PERC | | Degradation warranty | 0.55%/year | 0.54%/year | 0.7%/year typical | | Year-25 output | 84.8% | 83% | 80–82% | | Half-cut cells | Yes | Yes | Most products | | Perth pricing | Mid | Mid-premium | Lower | | AU warranty service | Adequate | Good | Variable |

The main advantage of LONGi over generic Tier-1 is the stronger degradation warranty (0.55% vs 0.7%/year) and the company's size and longevity — a large manufacturer is more likely to be honouring warranty claims in 15 years than a smaller or less established brand.

When to specify LONGi for Perth

LONGi is a sensible choice when:

• You want a mid-market panel with a strong degradation warranty at a competitive price
• Your installer has a strong LONGi supply relationship and warranty track record
• Maximising capacity per panel isn't critical (sufficient roof space available)
• Budget is a consideration but you want above-entry-level quality

Consider Q CELLS or REC Group instead if:

• You want maximum per-panel output (limited roof space)
• You prioritise a brand with a longer track record of AU warranty service
• You're prepared to pay a modest premium for the Q CELLS degradation guarantee or the REC Alpha's superior temperature performance

LONGi Hi-MO panels are one of the most commonly installed solar panels in Perth — solid mid-tier quality, 0.55%/year degradation warranty, half-cut cell technology, and competitive pricing ($1,000–$2,000 less than Q CELLS for a 10kW system). Good choice when budget matters but you want better than entry-level warranty terms. For long-term owners on limited roof space, Q CELLS or REC Alpha offer better per-panel output and superior temperature performance.