Decoding Solar Data Sheets: A Homeowners Guide

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A Homeowners Guide to Decoding Solar Data Sheets

You’ve made the exciting decision to investigate investing in a solar energy system. However, diving into the technical details on the solar data sheets can feel overwhelming. 

The amount of information, specifications, and jargon surrounding solar energy equipment can be a lot to digest. From understanding the efficiency ratings of solar panels to deciphering the various protection features of inverters, the learning curve can be steep. 

In this guide, we’ll simplify things by breaking down how to read data sheets for solar panels and inverters. By the end, you’ll have the knowledge to make informed decisions about your solar energy system.

Solar Panels

Solar panels, also known as modules, are the solar components that take center stage. Solar panels soak up the sunshine and collect the direct current (DC) energy from the sunshine to send to the inverter. 

When talking with your sales consultant about your solar panels, you may hear a couple of main features: brand, wattage, and color.

  • Brand: Solar panels come from various manufacturers, each offering different levels of quality, efficiency, and warranty. 
  • Wattage: Wattage refers to the power output of each solar panel. This indicates how much electricity the panel can produce under testing conditions. Common residential wattages range from 300 to over 450. 
  • Color: Solar panels come in different colors, typically black or blue.
    • Blue-on-White Panels: These are panels typically seen on older installations. The panels are blue solar cells, with a white backsheet, and silver frame. 
    • Black-on-Black Panels: More modern panels are known as black-on-black, which is a black solar cell, with a black backsheet, and black frame. 
    • Black-on-White: Similar to black-on-black panels, these panels have black solar cells, white backsheets, and black frames. 

Putting all of this together, you may hear your solar consultant say “REC 410’s black on black” or “QCell 370’s black on white”

Color combinations of solar panels

Solar Inverters

Solar inverters are the brains of your solar energy system. They convert the direct current (DC) electricity generated by your solar panels into alternating current (AC), which is the type of power used by your home.

When talking with your sales consultant about your solar inverter you will likely hear the words string inverter, string inverter with power optimizers, and microinverter.

  • String Inverter: A string inverter has all the solar panels connected in a series, like a string of holiday lights. They send the DC energy generated to one main inverter, which changes (inverts) the energy to alternating current (AC). 
  • Power Optimizers: While not an inverter themselves, work in conjunction with string inverters. Power optimizers are attached to each solar panel, allowing the panels on the string to function independently. The DC energy generated by the panels is sent to a main inverter to be converted to AC. 
  • Microinverter: A microinverter allows each solar panel to function with its own tiny inverter. Microinverters are affixed to each solar panel and convert DC to AC right there on the rooftop.

Decoding Solar Data Sheets

Data sheets or specification sheets, outline the technical details of the solar components. These are created by the manufacturer and may be provided in your proposal. As a check and balance, be sure to match the model listed on your proposal with the solar data sheet to ensure accurate information for the exact components your system has been designed with. 

Solar Panel Data Sheets

The panel solar data sheets detail the power output and efficiency to help you choose the best panels. When reviewing the solar data sheets for solar panels, focus on these areas:

  • Maximum Power Output (MPP): This is the panel wattage rating, which is the amount of electricity each solar panel can produce under optimal conditions. The higher the wattage the more electricity produced. 
  • Efficiency: Panel efficiency measures how well the panel converts sunlight to electricity. Look for panels with an efficiency rating between 18-22% as these panels operate more efficiently allowing you to need fewer panels to meet your energy needs.
  • Degradation Rate: Degradation measures how much a panel’s efficiency decreases each year. Typically, panels experience higher degradation in the first year (around 2-3%) and then stabilize to a lower annual rate (around 0.5% per year) for the remaining lifespan. After the initial drop, performance decreases more slowly, ensuring long-term efficiency and reliability. Look for a first-year degradation rate of 2-3% and a subsequent rate of 0.5% or less.
  • Manufacturer Warranty: Solar panel warranties typically cover product, power, and labor. Here’s what to look for:
    • Product and Power Warranty: These warranties usually range between 10-25 years for malfunctioning components which does not include accidents or “acts of God”.
    • Product Warranty: Covers defects in materials and ensures the physical components function properly.
    • Power/Performance Warranty: Guarantees the panel will produce a certain percentage of its rated power output over a specific period.
    • Labor Warranty: This warranty covers the installer for repairs and replacements and does not provide reimbursement to the homeowner. Homeowners should refer to their purchase agreement for information regarding labor warranty coverage.  

Each manufacturer offers different coverage terms. For detailed warranty information, ask your solar consultant for the warranty details page or visit the manufacturer’s website.

Inverter Data Sheets

The inverter solar data sheets detail the inverters capabilities and efficiency to help you choose the best inverter. When reviewing the solar data sheets for inverters, focus on these areas:

  • AC Power Output: This shows the maximum strength of the inverter. It should be able to handle all the power your solar panels produce. 
    • String Inverter and String Inverters with Power Optimizer: If you have 20 panels rated at 405 watts each, your total system power output is 20 x 405 = 8100w (watts) or 8.1 kW (kilowatts). The inverters’ maximum output should be slightly below or above.  It is normal for solar designs to slightly oversize the inverter to ensure efficiency.
    • Microinverters: If you have a 405-watt panel, you will want your maximum output to show close to or above the panel wattage.
  • Maximum Efficiency: Efficiency tells you how good the inverter is at converting solar energy (DC) into the type of electricity your home uses (AC). Look for an efficiency rating of 95% or higher as this gives you more usable solar power in your home instead of being lost in the conversion from DC to AC.
  • Manufacturer Warranty: Inverters come with a limited warranty that ranges from 5-15 years with options to extend coverage. Make sure to discuss the warranty coverage for the inverter with your solar consultant and review the manufacturer’s limited warranty data to better understand the coverage. 

Testing Certifications

For all solar components, ensure the equipment has the following certifications for safety, performance, and regulatory compliance. Typically, you will see the logo on the datasheet from 1-3 of these entities:

Testing Certification Centers Logos on Displayed on Data Sheets

Solar Insure’s Approved Vendor List (AVL)

If you are still unsure of the solar components and reliability, Solar Insure has established the Approved Vendor list which rigorously evaluates manufacturers for their safety, reliability, and stability. Learn more about the AVL, check out our recent article here. 

By familiarizing yourself with solar data sheets, you can confidently navigate the complexities of solar panel and inverter specifications. This knowledge empowers you to choose the best options for your home, ensuring your solar system is efficient, safe, and reliable.

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