LONGi Hi-MO X6 445W vs LONGi Hi-MO 7 620W
The LONGi Hi-MO 7 620W wins this comparison by a decisive margin. It leads in efficiency (23% vs 22%) and matches or exceeds on warranty (12 vs 12 years). For most residential installations, the LONGi Hi-MO 7 620W is the stronger choice.
Key Differences
- • LONGi Hi-MO X6 445W is rated at 445W while LONGi Hi-MO 7 620W is rated at 620W, a 175W difference.
- • LONGi Hi-MO 7 620W achieves 23% efficiency vs 22% for the other, a 1.0 percentage point gap.
- • Both carry matching 12-year product warranties.
- • LONGi Hi-MO 7 620W has a superior temperature coefficient of -0.28%/°C vs -0.29%/°C, retaining more power in hot climates.
- • LONGi Hi-MO X6 445W uses TOPCon N-type cells while LONGi Hi-MO 7 620W uses HPBC (Back Contact N-type) cells, representing different technology generations.
Specifications Breakdown
Module Efficiency
The LONGi Hi-MO 7 620W achieves 23% module efficiency compared to LONGi Hi-MO X6 445W's 22%, meaning LONGi Hi-MO 7 620W converts 1.0 percentage points more sunlight into electricity per square meter. In practical terms, the LONGi Hi-MO X6 445W produces 227.9 watts per square meter of panel area while the LONGi Hi-MO 7 620W produces 229.3 W/m². For rooftop installations where space is limited, this efficiency gap determines how many kilowatts you can fit on your available roof area. Over a 25-year system life, even a small efficiency advantage compounds into meaningful additional energy production.
Power Output
The LONGi Hi-MO 7 620W delivers 620W per panel versus 445W for the LONGi Hi-MO X6 445W, a 175W difference per module. To build an 8 kW residential system, you would need 18 LONGi Hi-MO X6 445W panels or 13 LONGi Hi-MO 7 620W panels. Choosing the higher-wattage option saves 5 panels, reducing total racking hardware, wiring, and installation labor costs. Higher wattage per panel is particularly valuable for commercial-scale installations where panel count directly impacts balance-of-system costs.
Temperature Coefficient
The LONGi Hi-MO 7 620W has a temperature coefficient of -0.28%/°C versus -0.29%/°C for the LONGi Hi-MO X6 445W. On a hot summer day when cell temperature reaches 65°C (40°C above the 25°C STC baseline), the LONGi Hi-MO 7 620W retains 94.4% of its rated power while the other retains 94.2%. While the numerical gap is modest, it still accumulates over decades of summer production, especially in southern latitudes with prolonged peak heat hours.
Warranty Coverage
The LONGi Hi-MO X6 445W is backed by a 12-year product warranty and 25-year performance guarantee, while the LONGi Hi-MO 7 620W offers 12-year product and 30-year performance coverage. Both offer identical product warranty duration. Based on their published degradation rates (1% first year then 0.4%/year for LONGi Hi-MO X6 445W; 0.5% first year then 0.35%/year for LONGi Hi-MO 7 620W), after 25 years the LONGi Hi-MO X6 445W should retain approximately 89.4% of original output versus 91.1% for the LONGi Hi-MO 7 620W. This 1.7 percentage point gap in end-of-life output meaningfully impacts lifetime energy economics.
Physical Dimensions & Weight
The LONGi Hi-MO X6 445W measures 1722×1134×30mm and weighs 21.5 kg, while the LONGi Hi-MO 7 620W measures 2384×1134×35mm at 31 kg. 1.95 m² of panel area for the LONGi Hi-MO X6 445W versus 2.70 m² for the LONGi Hi-MO 7 620W. The LONGi Hi-MO X6 445W is 9.5 kg lighter per panel, which reduces structural load requirements on the roof and makes handling easier during installation. For a 20-panel system, that is a total weight difference of 190 kg. The more compact LONGi Hi-MO X6 445W may be easier to fit on irregularly shaped or space-limited rooftops.
Specification Comparison
| Specification | LONGi Hi-MO X6 445W | LONGi Hi-MO 7 620W |
|---|---|---|
| Power | 445W | 620W |
| Efficiency | 22% | 23% |
| Power Density | 21.2 W/sq ft | 21.3 W/sq ft |
| Cell Type | TOPCon N-type | HPBC (Back Contact N-type) |
| Bifacial | Yes | Yes |
| Weight | 21.5 kg | 31 kg |
| Temp Coefficient | -0.29%/°C | -0.28%/°C |
| Snow Load | 5400 Pa | 5400 Pa |
| Wind Load | 2400 Pa | 2400 Pa |
| Product Warranty | 12 years | 12 years |
| Performance Warranty | 25 years | 30 years |
| Degradation (Year 1) | 1% | 0.5% |
| Annual Degradation | 0.4% | 0.35% |
| Country | China | China |
5-Dimension Head-to-Head Analysis
1. Efficiency & Power Density
Winner: LONGi Hi-MO 7 620WThe LONGi Hi-MO 7 620W achieves 23% efficiency versus 22% — a 1.0 percentage point advantage. On a typical 30-panel residential roof, this translates to approximately 5.3 kW more total system capacity, or 24 kWh more annual production in an average US location.
2. Hot Climate Performance
Winner: LONGi Hi-MO 7 620WThe LONGi Hi-MO 7 620W has a better temperature coefficient of -0.28%/°C versus -0.29%/°C. On a 45°C summer day (20°C above STC), the winner retains 94.4% of rated power versus 94.2%. The difference is modest but accumulates over 25 years of summer production.
3. Durability & Warranty
Winner: LONGi Hi-MO 7 620WLONGi Hi-MO 7 620W degrades more slowly at 0.35% per year versus 0.4%. After 25 years, expect 89.4% vs 91.1% of original output for LONGi Hi-MO X6 445W and LONGi Hi-MO 7 620W respectively.
4. Power Output
Winner: LONGi Hi-MO 7 620WThe LONGi Hi-MO 7 620W delivers 620W versus 445W per panel — 175W more. For an 8 kW system, you need 13 panels with the higher-wattage option versus 18 panels, saving 5 panels and the associated racking and labor costs.
5. Cell Technology
Winner: LONGi Hi-MO 7 620WThe LONGi Hi-MO X6 445W uses TOPCon N-type: TOPCon (Tunnel Oxide Passivated Contact) adds a thin tunnel oxide layer to reduce recombination losses, achieving higher efficiency than PERC while being manufacturable on existing production lines. The LONGi Hi-MO 7 620W uses HPBC (Back Contact N-type): HPBC (Hybrid Passivated Back Contact) is a proprietary LONGi architecture combining back-contact design with advanced passivation for both high efficiency and aesthetic uniformity. HPBC (Back Contact N-type) represents a newer generation technology with a longer performance runway as manufacturing matures.
LONGi Hi-MO X6 445W
The Hi-MO X6 is LONGi's TOPCon N-type line offering 445W in a compact format, well-suited for space-constrained residential rooftops.
Pros
- + Compact size for residential roofs
- + Good N-type TOPCon efficiency
- + Advanced technology
- + Budget-friendly
Cons
- - Lower wattage than larger models
- - Mid-range efficiency for N-type
- - Less suited for very large roofs
LONGi Hi-MO 7 620W
The Hi-MO 7 620W is LONGi's highest-output panel using proprietary HPBC (Hybrid Passivated Back Contact) technology for exceptional efficiency. Newer LR7/LR8 variants support 620W+ output.
Pros
- + Highest LONGi output
- + HPBC cutting-edge back-contact technology
- + 23.0% efficiency
- + Excellent degradation profile
Cons
- - Very large form factor
- - Premium pricing
- - New technology
Choose LONGi Hi-MO X6 445W If...
- ✓ You prefer newer cell technology with a longer performance improvement runway
- ✓ Homeowners wanting N-type TOPCon technology in a compact residential format.
Choose LONGi Hi-MO 7 620W If...
- ✓ Your roof space is limited and you need maximum power per panel
- ✓ You want fewer panels to reach your target system size, reducing racking and labor costs
- ✓ You live in a hot climate (Arizona, Texas, Florida) where heat performance matters
- ✓ You want maximum output retention over the system's 25-30 year lifespan
- ✓ Large installations wanting LONGi's most advanced HPBC technology.
Our Recommendation
The LONGi Hi-MO 7 620W is the decisive winner in this solar panel comparison, outperforming the LONGi Hi-MO X6 445W in 5 of 5 dimensions. Unless you have a specific requirement that the LONGi Hi-MO X6 445W uniquely addresses, the LONGi Hi-MO 7 620W is the stronger choice for virtually every installation scenario.
Frequently Asked Questions
Which is better, LONGi Hi-MO X6 445W or LONGi Hi-MO 7 620W?
The LONGi Hi-MO 7 620W wins this comparison by a decisive margin. It leads in efficiency (23% vs 22%) and matches or exceeds on warranty (12 vs 12 years). For most residential installations, the LONGi Hi-MO 7 620W is the stronger choice.
Which panel is more efficient, LONGi Hi-MO X6 445W or LONGi Hi-MO 7 620W?
The LONGi Hi-MO 7 620W at 23% module efficiency. Higher efficiency means more watts per square foot of roof space, which is critical for space-constrained installations. The difference of 1.0 percentage points translates to approximately 175W per panel under standard test conditions.
Which has a better warranty, LONGi Hi-MO X6 445W or LONGi Hi-MO 7 620W?
The LONGi Hi-MO X6 445W comes with a 12-year product warranty and 25-year performance guarantee. The LONGi Hi-MO 7 620W offers 12-year product and 30-year performance warranties. Both offer identical warranty terms.
Which panel performs better in hot weather?
The LONGi Hi-MO X6 445W has a temperature coefficient of -0.29%/°C and the LONGi Hi-MO 7 620W is -0.28%/°C. LONGi Hi-MO 7 620W retains more power in heat — important in states like Arizona, Texas, and Florida. A lower (less negative) temperature coefficient is better.
How many LONGi Hi-MO X6 445W vs LONGi Hi-MO 7 620W panels do I need for an 8 kW system?
For an 8 kW system: you need 18 LONGi Hi-MO X6 445W panels (445W each) or 13 LONGi Hi-MO 7 620W panels (620W each). The LONGi Hi-MO 7 620W requires fewer panels, saving on racking hardware and installation labor.
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Last updated: February 2026