JA Solar JAM78S30 590W vs Hyundai HiE-S485VG
The Hyundai HiE-S485VG wins this comparison by a clear margin. It offers better long-term durability with 25-year warranty. For most residential installations, the Hyundai HiE-S485VG is the stronger choice.
Key Differences
- • JA Solar JAM78S30 590W is rated at 590W while Hyundai HiE-S485VG is rated at 485W, a 105W difference.
- • JA Solar JAM78S30 590W achieves 22.6% efficiency vs 22% for the other, a 0.6 percentage point gap.
- • Hyundai HiE-S485VG comes with a 25-year product warranty vs 15 years for the other.
- • JA Solar JAM78S30 590W has a superior temperature coefficient of -0.28%/°C vs -0.3%/°C, retaining more power in hot climates.
Specifications Breakdown
Module Efficiency
The JA Solar JAM78S30 590W achieves 22.6% module efficiency compared to Hyundai HiE-S485VG's 22%, meaning JA Solar JAM78S30 590W converts 0.6 percentage points more sunlight into electricity per square meter. In practical terms, the JA Solar JAM78S30 590W produces 218.2 watts per square meter of panel area while the Hyundai HiE-S485VG produces 222.9 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 JA Solar JAM78S30 590W delivers 590W per panel versus 485W for the Hyundai HiE-S485VG, a 105W difference per module. To build an 8 kW residential system, you would need 14 JA Solar JAM78S30 590W panels or 17 Hyundai HiE-S485VG panels. Choosing the higher-wattage option saves 3 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 JA Solar JAM78S30 590W has a temperature coefficient of -0.28%/°C versus -0.3%/°C for the Hyundai HiE-S485VG. On a hot summer day when cell temperature reaches 65°C (40°C above the 25°C STC baseline), the JA Solar JAM78S30 590W retains 94.4% of its rated power while the other retains 94.0%. 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 JA Solar JAM78S30 590W is backed by a 15-year product warranty and 30-year performance guarantee, while the Hyundai HiE-S485VG offers 25-year product and 25-year performance coverage. The Hyundai HiE-S485VG provides 10 additional years of defect protection, covering manufacturing issues, material failures, and premature performance loss. Based on their published degradation rates (1% first year then 0.4%/year for JA Solar JAM78S30 590W; 1% first year then 0.4%/year for Hyundai HiE-S485VG), after 25 years the JA Solar JAM78S30 590W should retain approximately 89.4% of original output versus 89.4% for the Hyundai HiE-S485VG. The end-of-life output levels are closely matched.
Physical Dimensions & Weight
The JA Solar JAM78S30 590W measures 2384×1134×35mm and weighs 31 kg, while the Hyundai HiE-S485VG measures 2094×1039×35mm at 24.5 kg. 2.70 m² of panel area for the JA Solar JAM78S30 590W versus 2.18 m² for the Hyundai HiE-S485VG. The Hyundai HiE-S485VG is 6.5 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 130 kg. The more compact Hyundai HiE-S485VG may be easier to fit on irregularly shaped or space-limited rooftops.
Specification Comparison
| Specification | JA Solar JAM78S30 590W | Hyundai HiE-S485VG |
|---|---|---|
| Power | 590W | 485W |
| Efficiency | 22.6% | 22% |
| Power Density | 20.3 W/sq ft | 20.7 W/sq ft |
| Cell Type | TOPCon N-type | TOPCon N-type |
| Bifacial | No | No |
| Weight | 31 kg | 24.5 kg |
| Temp Coefficient | -0.28%/°C | -0.3%/°C |
| Snow Load | 5400 Pa | 5400 Pa |
| Wind Load | 2400 Pa | 2400 Pa |
| Product Warranty | 15 years | 25 years |
| Performance Warranty | 30 years | 25 years |
| Degradation (Year 1) | 1% | 1% |
| Annual Degradation | 0.4% | 0.4% |
| Country | China | South Korea |
5-Dimension Head-to-Head Analysis
1. Efficiency & Power Density
Winner: JA Solar JAM78S30 590WThe JA Solar JAM78S30 590W achieves 22.6% efficiency versus 22% — a 0.6 percentage point advantage. On a typical 30-panel residential roof, this translates to approximately 3.1 kW more total system capacity, or 15 kWh more annual production in an average US location.
2. Hot Climate Performance
Winner: JA Solar JAM78S30 590WThe JA Solar JAM78S30 590W has a better temperature coefficient of -0.28%/°C versus -0.3%/°C. On a 45°C summer day (20°C above STC), the winner retains 94.4% of rated power versus 94.0%. The difference is modest but accumulates over 25 years of summer production.
3. Durability & Warranty
Winner: Hyundai HiE-S485VGHyundai HiE-S485VG leads with a 25-year product warranty versus 15 years. After 25 years, expect 89.4% vs 89.4% of original output for JA Solar JAM78S30 590W and Hyundai HiE-S485VG respectively.
4. Power Output
Winner: JA Solar JAM78S30 590WThe JA Solar JAM78S30 590W delivers 590W versus 485W per panel — 105W more. For an 8 kW system, you need 14 panels with the higher-wattage option versus 17 panels, saving 3 panels and the associated racking and labor costs.
5. Cell Technology
Winner: TieBoth panels use TOPCon N-type cell technology. No technology advantage for either product.
JA Solar JAM78S30 590W
JA Solar's JAM78S30 is a high-wattage N-type TOPCon module achieving 22.6% efficiency for large-scale installations.
Pros
- + Very high 590W output
- + Excellent efficiency
- + Low temperature coefficient
- + Bifacial design
Cons
- - Very large and heavy
- - Requires heavy-duty mounting
- - Not for small roofs
Hyundai HiE-S485VG
The Hyundai HiE-S485VG is a 485W TOPCon N-type panel manufactured in South Korea by Hyundai Energy Solutions, a division of the Hyundai conglomerate. The N-type TOPCon cell technology delivers 22.0% module efficiency with a -0.30%/°C temperature coefficient — significantly better than PERC alternatives in hot climates. Hyundai's Korean manufacturing offers non-Chinese supply chain diversification for buyers concerned about tariffs or UFLPA compliance. The 25+25 year warranty is backed by the Hyundai corporate group's financial stability.
Pros
- + South Korean manufacturing — non-Chinese supply chain diversification
- + TOPCon N-type with 22.0% efficiency and -0.30%/°C temp coefficient
- + Backed by Hyundai conglomerate's financial strength for warranty assurance
- + 25-year product and performance warranties
- + Lower degradation than PERC — 1.0% first year, 0.4% annual
- + Competitively priced for a non-Chinese Tier-1 panel
Cons
- - Lower brand recognition in US solar market than LONGi or JinkoSolar
- - 132-cell format slightly larger than standard 108/120-cell residential panels
- - US dealer network smaller than mainstream brands
- - 485W is mid-range — competitors offer 500W+ in similar sizes
Choose JA Solar JAM78S30 590W 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 prefer newer cell technology with a longer performance improvement runway
- ✓ Large commercial or ground-mount systems requiring maximum output.
Choose Hyundai HiE-S485VG If...
- ✓ Long-term warranty protection is a top priority and you plan to stay in your home for 25+ years
- ✓ You prefer newer cell technology with a longer performance improvement runway
- ✓ Homeowners and commercial buyers seeking Tier-1 Korean-manufactured TOPCon panels with strong corporate warranty backing and non-Chinese supply chain.
Our Recommendation
We recommend the Hyundai HiE-S485VG for most buyers in this comparison. It wins 1 of 5 key dimensions and offers a clear advantage in the metrics that matter most for a solar panel purchase. The JA Solar JAM78S30 590W remains a good product, but the Hyundai HiE-S485VG delivers better overall value for the majority of installations.
Frequently Asked Questions
Which is better, JA Solar JAM78S30 590W or Hyundai HiE-S485VG?
The Hyundai HiE-S485VG wins this comparison by a clear margin. It offers better long-term durability with 25-year warranty. For most residential installations, the Hyundai HiE-S485VG is the stronger choice.
Which panel is more efficient, JA Solar JAM78S30 590W or Hyundai HiE-S485VG?
The JA Solar JAM78S30 590W at 22.6% module efficiency. Higher efficiency means more watts per square foot of roof space, which is critical for space-constrained installations. The difference of 0.6 percentage points translates to approximately 105W per panel under standard test conditions.
Which has a better warranty, JA Solar JAM78S30 590W or Hyundai HiE-S485VG?
The JA Solar JAM78S30 590W comes with a 15-year product warranty and 30-year performance guarantee. The Hyundai HiE-S485VG offers 25-year product and 25-year performance warranties. Hyundai HiE-S485VG provides 10 additional years of product coverage.
Which panel performs better in hot weather?
The JA Solar JAM78S30 590W has a temperature coefficient of -0.28%/°C and the Hyundai HiE-S485VG is -0.3%/°C. JA Solar JAM78S30 590W retains more power in heat — important in states like Arizona, Texas, and Florida. A lower (less negative) temperature coefficient is better.
How many JA Solar JAM78S30 590W vs Hyundai HiE-S485VG panels do I need for an 8 kW system?
For an 8 kW system: you need 14 JA Solar JAM78S30 590W panels (590W each) or 17 Hyundai HiE-S485VG panels (485W each). The JA Solar JAM78S30 590W requires fewer panels, saving on racking hardware and installation labor.
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Last updated: February 2026