A 245 watt solar panel represents a specific era in solar technology that dominated the residential market from 2010-2016. While these panels are largely discontinued in favor of higher-efficiency alternatives, understanding their specifications, performance characteristics, and current market status remains crucial for homeowners with existing systems or those considering used panel purchases.
In 2025, the solar landscape has evolved dramatically. Modern panels typically range from 350-480 watts, offering significantly better efficiency and cost-per-watt ratios. However, 245W panels still serve specific applications and remain available in the used market, making this comprehensive analysis essential for informed decision-making.
What is a 245 Watt Solar Panel?
A 245 watt solar panel is a photovoltaic module designed to produce 245 watts of electrical power under Standard Test Conditions (STC). These panels typically feature 60 solar cells arranged in a 6×10 configuration and were manufactured primarily using polycrystalline or monocrystalline silicon technology.
Key characteristics of 245W panels include:
- Power output: 245 watts (STC rating)
- Voltage range: 29-31V (maximum power voltage)
- Current range: 7.9-8.2 amperes (maximum power current)
- Efficiency: 14-20% depending on cell technology
- Dimensions: Approximately 65″ x 39″ x 1.6″
- Weight: 40-45 pounds
Current Market Position and Availability
As of 2025, 245 watt solar panels are considered legacy products. Major manufacturers like Trina Solar, Canadian Solar, and SolarWorld have discontinued these models in favor of higher-wattage alternatives. The primary sources for 245W panels today include:
- Used panel dealers and surplus inventory
- Replacement panels for existing systems
- Specialty applications requiring specific voltage characteristics
- Budget-conscious installations in developing markets
Technical Specifications Deep Dive
Standard Electrical Characteristics
Understanding the electrical specifications of 245W panels is crucial for system design and compatibility assessment. Here are the typical ranges across major manufacturers:
Voltage Specifications:
- Open Circuit Voltage (Voc): 37-38V
- Maximum Power Voltage (Vmp): 29.9-31V
- Temperature Coefficient: -0.35% to -0.45% per °C
Current Specifications:
- Short Circuit Current (Isc): 8.6-8.8A
- Maximum Power Current (Imp): 7.9-8.2A
- Fuse Rating: 15A maximum
Physical Dimensions and Weight
Most 245W panels share similar physical characteristics, making them interchangeable in existing mounting systems:
- Length: 1640-1650mm (64.5-65″)
- Width: 990-992mm (38.7-39″)
- Thickness: 35-40mm (1.4-1.6″)
- Weight: 18.6-20kg (41-44 lbs)
- Frame: Anodized aluminum alloy
- Glass: 3.2mm tempered solar glass
Cell Technology Comparison
Monocrystalline 245W Panels:
- Higher efficiency: 20-24%
- Better low-light performance
- Premium pricing when new
- Darker, uniform appearance
- Examples: SolarWorld SW245MONO
Polycrystalline 245W Panels:
- Moderate efficiency: 15-20%
- Cost-effective manufacturing
- Blue, speckled appearance
- Slightly higher temperature coefficient
- Examples: Trina TSM-245PA05, Canadian Solar CS6P-245P
Top 245 Watt Solar Panel Models Analysis
Trina TSM-245PA05 Comprehensive Review
The Trina TSM-245PA05 was one of the most popular 245W panels during its production run, known for reliability and consistent performance.
Key Specifications:
- Technology: 60-cell polycrystalline
- Efficiency: 15.0%
- Vmp: 30.2V | Imp: 8.13A
- Voc: 37.5V | Isc: 8.68A
- Dimensions: 1650 x 992 x 35mm
- Weight: 18.6kg (41 lbs)
- Frame: Silver anodized aluminum
- Connector: MC4
Performance Characteristics:
- PTC Rating: 222.9W (91% of STC)
- Power tolerance: 0/+3%
- Temperature coefficient: -0.45%/°C
- Wind load: 2400Pa
- Snow load: 5400Pa
Canadian Solar CS6P-245P Detailed Analysis
Canadian Solar’s CS6P-245P offered excellent value proposition with robust construction and reliable performance.
Technical Specifications:
- Cell type: 60-cell polycrystalline
- Module efficiency: 15.1%
- Vmp: 30.0V | Imp: 8.17A
- Voc: 37.1V | Isc: 8.74A
- Dimensions: 1640 x 992 x 40mm
- Weight: 20kg (44.1 lbs)
- Power tolerance: 0/+5W
Notable Features:
- Industry-leading PTC rating in California
- ISO:TS16949 certified manufacturing
- Mechanical load test: 5400Pa snow load
- Maximum system voltage: 600V DC
Side-by-Side Comparison Table
| Model | Technology | Efficiency | Vmp/Imp | Weight | Key Feature |
|---|---|---|---|---|---|
| Trina TSM-245PA05 | Poly | 15.0% | 30.2V/8.13A | 41 lbs | High reliability |
| Canadian Solar CS6P-245P | Poly | 15.1% | 30.0V/8.17A | 44 lbs | Best value |
| SolarWorld SW245MONO | Mono | 15.9% | N/A | N/A | German quality |
Performance and Efficiency Analysis
Real-World Power Output Expectations
While 245W panels are rated at 245 watts under STC, real-world performance varies significantly based on environmental conditions.
Typical Performance Ranges:
- Peak conditions: 220-240W actual output
- Average conditions: 180-210W typical output
- Poor conditions: 50-120W (cloudy/early morning)
- Annual capacity factor: 15-25% depending on location
Efficiency Ratings and Practical Impact
The efficiency rating directly impacts space requirements and system economics:
Efficiency Comparison:
- 14% efficiency: Requires ~17.5 sq ft per panel
- 16% efficiency: Requires ~15.3 sq ft per panel
- 20% efficiency: Requires ~12.3 sq ft per panel
For a typical 5kW system using 245W panels, you would need approximately 20-21 panels, requiring 300-350 square feet of roof space.
Temperature Coefficient Impact
Temperature coefficients significantly affect performance in hot climates:
- Polycrystalline panels: -0.45%/°C typical
- Monocrystalline panels: -0.38%/°C typical
- Performance loss at 25°C above STC: 9-11% power reduction
In Phoenix, Arizona (average cell temperature 65°C), a 245W panel might only produce 200-210W during peak summer conditions.
Installation and System Design Considerations
Optimal System Configurations
Designing systems with 245W panels requires careful consideration of string sizing and inverter compatibility.
String Sizing Guidelines:
- Minimum string size: 8-10 panels (depending on inverter)
- Maximum string size: 15-18 panels (600V system limit)
- Optimal string size: 12-14 panels for most applications
Inverter Compatibility
Popular inverter options for 245W panel systems include:
String Inverters:
- SMA Sunny Boy 3000-7000 series
- Fronius Primo 3.0-8.2 kW
- SolarEdge SE3000-SE7600
Microinverters:
- Enphase M215 (discontinued, used market)
- Enphase M250 (better match for 245W)
- APSystems YC500 (dual-panel microinverter)
Roof Space Requirements
For optimal performance, 245W panels require:
- Panel spacing: 6-12 inches between rows
- Roof area per panel: 20-25 sq ft including spacing
- Minimum roof size for 5kW system: 400-500 sq ft
- Orientation: South-facing preferred, east/west acceptable
- Tilt angle: Latitude ±15° for optimal performance
Cost Analysis and Value Proposition
Current Pricing Trends
As of 2025, 245W panel pricing reflects their legacy status:
Used Panel Pricing:
- Good condition: $0.30-0.50 per watt
- Fair condition: $0.20-0.35 per watt
- Poor condition/cosmetic issues: $0.15-0.25 per watt
New Old Stock (NOS):
- Premium brands: $0.60-0.80 per watt
- Standard brands: $0.45-0.65 per watt
Cost Comparison with Modern Panels
Modern 400W+ Panel Pricing (2025):
- New panels: $2.56 per watt average before incentives
- Cost per watt advantage: Modern panels now offer better long-term value despite higher upfront costs
- Installation cost savings: Fewer panels = lower labor costs
Total System Cost Implications
While used 245W panels appear cheaper per watt, total system costs tell a different story:
5kW System Comparison:
- 245W panels (21 panels): $6,000-8,500 total
- 450W panels (12 panels): $7,500-9,500 total
- Installation cost difference: $1,000-2,000 savings with fewer panels
For homeowners exploring different payment options, there are various solar panel financing options available to make modern systems more accessible.
Warranty and Reliability Assessment
Standard Warranty Terms
Original warranties for 245W panels typically included:
Product Warranty:
- Duration: 10-12 years
- Coverage: Manufacturing defects, frame issues
- Current status: Most warranties expired or transferred
Performance Warranty:
- Duration: 25 years linear
- Year 1: 97-98% of rated power
- Annual degradation: 0.7-0.8% maximum
- Year 25: 80-82% minimum power output
Manufacturer Reliability Track Records
Tier 1 Manufacturers (High Reliability):
- Canadian Solar: Strong reliability record
- Trina Solar: Good performance, widespread deployment
Common Issues and Failure Modes:
- Snail trails: Cosmetic discoloration (minimal performance impact)
- Potential Induced Degradation (PID): Performance loss in high-voltage systems
- Solder bond failures: Connection issues in older panels
- Frame corrosion: Coastal installations particularly affected
Modern Alternatives and Upgrade Considerations
Why 245W Panels Are Largely Discontinued
The solar industry’s evolution has made 245W panels obsolete for several reasons:
- Manufacturing efficiency: Larger wafers and improved processes
- Installation cost reduction: Fewer panels needed for same capacity
- Improved efficiency: Modern panels achieve 20-22% efficiency
- Better economics: Lower cost per watt for higher-wattage panels
Modern Panel Alternatives
Direct Replacement Options (2025):
- 400-450W panels: Similar voltage, higher current
- Tier 1 recommendations: REC, Q CELLS, JA Solar, Jinko
- Efficiency range: 20-22% typical
- Pricing: $2.56 per watt average before incentives
High-Efficiency Alternatives:
- 500-600W panels: Maximum power density
- N-type technology: Lower degradation rates
- Bifacial options: Additional ground reflection gain
- Premium pricing: $0.60-0.90 per watt
Upgrade Path for Existing Systems
For homeowners with existing 245W systems considering upgrades:
Partial System Upgrades:
- Replace failed panels with modern equivalents
- Use power optimizers to match different panel types
- Consider microinverters for mixed systems
Complete System Replacement:
- Evaluate roof condition and mounting system
- Upgrade electrical infrastructure if needed
- Take advantage of current tax incentives
- Consider battery storage integration
Buying Guide and Recommendations
Where to Find 245W Panels
Used Panel Sources:
- Solar installers: Replacement inventory and decommissioned systems
- Online marketplaces: eBay, Facebook Marketplace, Craigslist
- Solar surplus dealers: Specialized used equipment vendors
- Utility-scale decommissions: Large quantities available
Quality Assessment Checklist:
- Visual inspection: Check for cracks, burn marks, frame damage
- Electrical testing: Verify voltage and current output
- Performance verification: Compare actual vs. rated output
- Documentation: Request original specifications and test data
Red Flags to Avoid
- No electrical testing data: Insist on performance verification
- Extensive physical damage: Cracked glass, bent frames
- Unknown storage conditions: Panels stored outdoors without protection
- Missing junction boxes: Expensive to replace
- Flood-damaged panels: Potential safety hazards
Installation and Maintenance Guide
Professional vs. DIY Installation
Professional Installation Recommended For:
- Grid-tied systems requiring utility interconnection
- Roof-mounted installations above single story
- Complex electrical configurations
- Jurisdictions requiring licensed installer
DIY Installation Suitable For:
- Ground-mounted off-grid systems
- Small supplemental installations
- Experienced DIY enthusiasts with electrical knowledge
- Non-grid-tied applications
Safety Precautions and Requirements
Essential Safety Equipment:
- OSHA-approved fall protection equipment
- Insulated tools rated for DC voltage
- Personal protective equipment (PPE)
- Voltage meters and testing equipment
Electrical Safety Considerations:
- Always test circuits before working
- Use proper DC-rated disconnects
- Follow NEC Article 690 requirements
- Install proper grounding and bonding
Ongoing Maintenance and Monitoring
Regular Maintenance Tasks:
- Visual inspections: Quarterly checks for damage
- Performance monitoring: Monthly output verification
- Cleaning: As needed based on soiling conditions
- Connection checks: Annual electrical inspection
To maintain optimal performance, many homeowners benefit from professional solar panel cleaning services that ensure panels operate at peak efficiency throughout their lifespan.
Performance Monitoring:
- Install production monitoring system
- Track monthly and annual energy production
- Compare actual vs. expected performance
- Identify underperforming panels or strings
Frequently Asked Questions
Are 245 watt solar panels still good in 2025?
245W panels can still be viable for specific applications, particularly in the used market. However, they’re generally not recommended for new installations due to poor cost-per-watt ratios compared to modern alternatives. They may make sense for system expansions or replacement panels in existing systems.
How much power does a 245W solar panel actually produce?
Real-world output typically ranges from 180-220W under normal conditions, with peak output reaching 220-240W under ideal conditions. Annual production depends heavily on location, with typical capacity factors of 15-25%.
How many 245 watt solar panels do I need for my home?
For an average U.S. home using 10,791 kWh annually (899 kWh monthly), you would need approximately 18-25 panels (4.4-6.1 kW system) depending on your location’s solar resource. However, modern 400W+ panels would be more cost-effective for new installations.
What’s the difference between 245W monocrystalline and polycrystalline panels?
Monocrystalline 245W panels typically offer 20-24% efficiency with better low-light performance and a uniform black appearance. Polycrystalline versions provide 15-20% efficiency with lower costs but slightly higher temperature coefficients and a blue, speckled appearance.
Can I mix 245W panels with modern higher-wattage panels?
Mixing panel types in the same string is not recommended due to current mismatch. However, you can use different panels in separate strings or employ power optimizers/microinverters to manage mixed systems effectively.
Where can I buy 245 watt solar panels in 2025?
New 245W panels are largely unavailable from major manufacturers. Used panels can be found through solar installers, online marketplaces, and surplus dealers. Prices range from $0.15-0.80 per watt depending on condition and source.
Are used 245W solar panels worth buying?
Used 245W panels can offer value for specific applications like off-grid systems, RV installations, or system expansions. However, for new grid-tied residential installations, modern panels typically provide better economics despite higher upfront costs.
How long will 245W solar panels last?
Quality 245W panels from Tier 1 manufacturers typically last 25-30 years with gradual performance degradation. Panels installed 10-15 years ago should still produce 85-90% of their original output.
What inverter should I use with 245W solar panels?
String inverters like SMA Sunny Boy, Fronius Primo, or SolarEdge models work well with 245W panels. For mixed systems or shading issues, consider microinverters like Enphase M250 or power optimizers.
Can 245W panels handle snow and wind loads?
Most 245W panels are rated for 2400Pa wind loads and 5400Pa snow loads, making them suitable for most residential applications. Always verify specific ratings for your local building codes and environmental conditions.
Conclusion: Making the Right Choice in 2025
While 245 watt solar panels played a crucial role in the solar industry’s growth, their relevance in 2025 is primarily limited to specific use cases. For homeowners considering solar installations, modern 400W+ panels offer superior economics, efficiency, and installation advantages.
Consider 245W panels if:
- You need replacement panels for an existing system
- Budget constraints make used panels attractive
- You’re building an off-grid system with specific voltage requirements
- Your installation has unusual space or weight constraints
Choose modern alternatives if:
- You’re installing a new grid-tied system
- Maximizing roof space efficiency is important
- You want the best long-term economics
- Future expandability is a consideration
The solar industry’s rapid advancement means that while 245W panels served their purpose well, today’s technology offers compelling advantages that make them the preferred choice for most applications. Whether you choose legacy or modern panels, investing in solar energy remains one of the best decisions for reducing energy costs and environmental impact.
For personalized recommendations based on your specific situation, consult with certified solar installers who can evaluate your energy needs, roof conditions, and local incentives to determine the optimal solution for your home.