Post Detail

Buying solar is easier when you evaluate each component with clear criteria. This handbook provides a structured approach to selecting parts that work together efficiently and safely.

Step 1: Understand Module Technologies

1. Mono-PERC vs. TOPCon vs. HJT: all can perform well; focus on certified efficiency, temperature coefficient, and long-term reliability.
2. Key parameters:
   • Module wattage (W): higher wattage often means fewer modules and smaller footprint.
   • Efficiency (%): impacts roof area needed.
   • Temperature coefficient (e.g., −0.30 to −0.40%/°C): lower magnitude is better for hot climates.
   • Mechanical load ratings and PID/LID resistance.
3. Warranties:
   • Product: typically 12–15 years.
   • Performance: commonly 25–30 years with a final guaranteed output (e.g., 84–88%).

Step 2: Choose the Right Inverter Type

1. String inverter: cost-effective, easier service, central point of monitoring; performance depends on string uniformity.
2. Microinverter: module-level optimization and better shade tolerance; higher initial cost.
3. Power optimizers with string inverter: middle ground for shade or complex roofs.
4. Hybrid inverter: adds battery support, islanding, and energy management features.

Step 3: Match Inverter Features to Your Use Case

1. MPPT count and input voltage/current ranges for flexible stringing.
2. Anti-islanding protection and grid code compliance.
3. Communication and monitoring: Wi-Fi/LAN, RS-485, Modbus, cloud portal, open API if you need integration.
4. Protection: surge protection (Type II), AFCI/arc-fault detection where available, and rapid shutdown for safety.

Step 4: Battery Technology and Sizing

1. Chemistry: Lithium iron phosphate (LFP) is widely chosen for safety and cycle life.
2. Depth of discharge and cycle life: aim for ≥6000 cycles at 80–90% DoD for long-term value.
3. Scalability: rack-mount or modular packs allow future expansion.
4. BMS and inverter compatibility: confirm approved lists and communication protocols (CAN/RS-485).

Step 5: Balance-of-System Essentials

1. Mounting structures: hot-dip galvanized or aluminum, wind-rated, compatible with your roof.
2. Cabling and connectors: PV-rated, double-insulated DC cables, original MC4-type connectors, and proper crimping tools.
3. Protection devices: DC/AC isolators, fuses/breakers, SPD Type II on both DC and AC sides as appropriate.
4. Earthing and lightning: dedicated earth pits and bonding; consider a lightning arrestor in high-exposure areas.

Step 6: Evaluate Quality With Certifications

1. Panels: IEC 61215, IEC 61730, and independent lab results where available.
2. Inverters: IEC/EN compliance, grid code certificates.
3. Batteries: UN38.3 for transport, IEC 62619 or equivalent safety standards.

Step 7: Build a Shortlist With a Scorecard

Create a simple 10-point scorecard for each component:

Assign 1–10 scores and compute weighted totals to compare options objectively.

Step 8: Calculate Energy Yield and Savings

1. Use a conservative performance ratio (e.g., 75–80%) when estimating annual kWh.
2. Annual energy ≈ Array size (kW) × Peak sun hours per day × 365 × Performance ratio.
3. Estimate bill savings using your tariff, demand charges, and net-metering rules if applicable.
4. Consider degradation: panels typically lose ~0.4–0.6% per year.

Step 9: Plan for Operations and Maintenance

1. Include periodic cleaning, visual inspections, thermal scans (if available), and fastener torque checks.
2. Track inverter error logs and production reports; investigate long dips versus weather patterns.
3. Maintain spares: fuses, MC4 connectors, and a few extra modules if logistics are challenging.

Step 10: Contracting and Warranty Management

1. Ensure your contract includes a detailed bill of materials with exact models.
2. Capture serial numbers and commissioning data for all critical gear.
3. Clarify response times for service calls and warranty claim processes.
4. Keep all documents in a cloud folder shared with your installer and operations team.