LONGi Hi-MO 6 580W vs Canadian Solar CS6R 420W
The LONGi Hi-MO 6 580W wins this comparison by a clear margin. It leads in efficiency (22.3% vs 21%) and matches or exceeds on warranty (12 vs 12 years). For most residential installations, the LONGi Hi-MO 6 580W is the stronger choice.
Key Differences
- • LONGi Hi-MO 6 580W is rated at 580W while Canadian Solar CS6R 420W is rated at 420W, a 160W difference.
- • LONGi Hi-MO 6 580W achieves 22.3% efficiency vs 21% for the other, a 1.3 percentage point gap.
- • Both carry matching 12-year product warranties.
- • LONGi Hi-MO 6 580W uses PERC Mono Half-cut cells while Canadian Solar CS6R 420W uses PERC Mono cells, representing different technology generations.
Specifications Breakdown
Module Efficiency
The LONGi Hi-MO 6 580W achieves 22.3% module efficiency compared to Canadian Solar CS6R 420W's 21%, meaning LONGi Hi-MO 6 580W converts 1.3 percentage points more sunlight into electricity per square meter. In practical terms, the LONGi Hi-MO 6 580W produces 224.5 watts per square meter of panel area while the Canadian Solar CS6R 420W produces 215.1 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 6 580W delivers 580W per panel versus 420W for the Canadian Solar CS6R 420W, a 160W difference per module. To build an 8 kW residential system, you would need 14 LONGi Hi-MO 6 580W panels or 20 Canadian Solar CS6R 420W panels. Choosing the higher-wattage option saves 6 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
Both panels share an identical temperature coefficient of -0.34%/°C, meaning they lose power at the same rate as cell temperature rises above the 25°C standard test baseline. At 65°C cell temperature, both retain 93.2% of rated power. Neither panel has a thermal performance advantage, which makes this specification a non-factor in the comparison.
Warranty Coverage
The LONGi Hi-MO 6 580W is backed by a 12-year product warranty and 25-year performance guarantee, while the Canadian Solar CS6R 420W offers 12-year product and 25-year performance coverage. Both offer identical product warranty duration. Based on their published degradation rates (1.5% first year then 0.5%/year for LONGi Hi-MO 6 580W; 1.5% first year then 0.5%/year for Canadian Solar CS6R 420W), after 25 years the LONGi Hi-MO 6 580W should retain approximately 86.5% of original output versus 86.5% for the Canadian Solar CS6R 420W. The end-of-life output levels are closely matched.
Physical Dimensions & Weight
The LONGi Hi-MO 6 580W measures 2278×1134×35mm and weighs 28.4 kg, while the Canadian Solar CS6R 420W measures 1722×1134×30mm at 21 kg. 2.58 m² of panel area for the LONGi Hi-MO 6 580W versus 1.95 m² for the Canadian Solar CS6R 420W. The Canadian Solar CS6R 420W is 7.4 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 148 kg. The more compact Canadian Solar CS6R 420W may be easier to fit on irregularly shaped or space-limited rooftops.
Specification Comparison
| Specification | LONGi Hi-MO 6 580W | Canadian Solar CS6R 420W |
|---|---|---|
| Power | 580W | 420W |
| Efficiency | 22.3% | 21% |
| Power Density | 20.9 W/sq ft | 20.0 W/sq ft |
| Cell Type | PERC Mono Half-cut | PERC Mono |
| Bifacial | No | No |
| Weight | 28.4 kg | 21 kg |
| Temp Coefficient | -0.34%/°C | -0.34%/°C |
| Snow Load | 5400 Pa | 5400 Pa |
| Wind Load | 2400 Pa | 2400 Pa |
| Product Warranty | 12 years | 12 years |
| Performance Warranty | 25 years | 25 years |
| Degradation (Year 1) | 1.5% | 1.5% |
| Annual Degradation | 0.5% | 0.5% |
| Country | China | China |
5-Dimension Head-to-Head Analysis
1. Efficiency & Power Density
Winner: LONGi Hi-MO 6 580WThe LONGi Hi-MO 6 580W achieves 22.3% efficiency versus 21% — a 1.3 percentage point advantage. On a typical 30-panel residential roof, this translates to approximately 4.8 kW more total system capacity, or 22 kWh more annual production in an average US location.
2. Hot Climate Performance
Winner: TieBoth panels share a temperature coefficient of -0.34%/°C — identical heat tolerance.
3. Durability & Warranty
Winner: TieBoth panels offer identical 12-year product warranties and 0.5% annual degradation. Neither has a durability advantage.
4. Power Output
Winner: LONGi Hi-MO 6 580WThe LONGi Hi-MO 6 580W delivers 580W versus 420W per panel — 160W more. For an 8 kW system, you need 14 panels with the higher-wattage option versus 20 panels, saving 6 panels and the associated racking and labor costs.
5. Cell Technology
Winner: TieThe LONGi Hi-MO 6 580W uses PERC Mono Half-cut: PERC (Passivated Emitter Rear Cell) is the current mainstream technology, offering good efficiency at the lowest manufacturing cost. The Canadian Solar CS6R 420W uses PERC Mono: PERC (Passivated Emitter Rear Cell) is the current mainstream technology, offering good efficiency at the lowest manufacturing cost. Both are equivalent-generation technologies.
LONGi Hi-MO 6 580W
LONGi Hi-MO 6 is a high-performance PERC mono half-cut panel delivering 580W with 22.3% efficiency, ideal for residential and commercial rooftops.
Pros
- + High 22.3% efficiency
- + Proven PERC technology
- + Strong bifacial gain potential
- + Competitive pricing
Cons
- - Large physical size
- - Requires compatible racking
- - Limited US availability
Canadian Solar CS6R 420W
The CS6R is Canadian Solar's residential PERC workhorse delivering 420W in a compact, roof-friendly form factor.
Pros
- + Compact residential size
- + Affordable pricing
- + Proven track record
- + Easy installation
Cons
- - Older PERC technology
- - Standard performance
- - Higher degradation
Choose LONGi Hi-MO 6 580W 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
- ✓ Homeowners wanting high-output PERC performance at a competitive price.
Choose Canadian Solar CS6R 420W If...
- ✓ Budget residential installations from a bankable Tier 1 brand.
Our Recommendation
We recommend the LONGi Hi-MO 6 580W for most buyers in this comparison. It wins 2 of 5 key dimensions and offers a clear advantage in the metrics that matter most for a solar panel purchase. The Canadian Solar CS6R 420W remains a good product, but the LONGi Hi-MO 6 580W delivers better overall value for the majority of installations.
Frequently Asked Questions
Which is better, LONGi Hi-MO 6 580W or Canadian Solar CS6R 420W?
The LONGi Hi-MO 6 580W wins this comparison by a clear margin. It leads in efficiency (22.3% vs 21%) and matches or exceeds on warranty (12 vs 12 years). For most residential installations, the LONGi Hi-MO 6 580W is the stronger choice.
Which panel is more efficient, LONGi Hi-MO 6 580W or Canadian Solar CS6R 420W?
The LONGi Hi-MO 6 580W at 22.3% module efficiency. Higher efficiency means more watts per square foot of roof space, which is critical for space-constrained installations. The difference of 1.3 percentage points translates to approximately 160W per panel under standard test conditions.
Which has a better warranty, LONGi Hi-MO 6 580W or Canadian Solar CS6R 420W?
The LONGi Hi-MO 6 580W comes with a 12-year product warranty and 25-year performance guarantee. The Canadian Solar CS6R 420W offers 12-year product and 25-year performance warranties. Both offer identical warranty terms.
Which panel performs better in hot weather?
The LONGi Hi-MO 6 580W has a temperature coefficient of -0.34%/°C and the Canadian Solar CS6R 420W is -0.34%/°C. Both handle heat equally. A lower (less negative) temperature coefficient is better.
How many LONGi Hi-MO 6 580W vs Canadian Solar CS6R 420W panels do I need for an 8 kW system?
For an 8 kW system: you need 14 LONGi Hi-MO 6 580W panels (580W each) or 20 Canadian Solar CS6R 420W panels (420W each). The LONGi Hi-MO 6 580W requires fewer panels, saving on racking hardware and installation labor.
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Last updated: February 2026