A Grade vs B Grade Solar Panels: What Is the Difference?
A-grade solar panels pass the maker's full quality checks and are sold with the normal warranty. B-grade panels have defects found at the factory, such as cracks, colour marks or lower output, and usually carry a weaker warranty or none. The problem in Pakistan is that some B-grade or C-grade panels are sold as A-grade. LONGi itself has warned buyers about this. Here is how to tell the difference before you pay.
Updated 12 November 2026
What the grades mean
Panel makers sort cells and finished panels by quality (Sinovoltaics grading guide):
- A grade: no visible defects, output at or above the label, passes electroluminescence (EL) and flash tests. Sold under the brand with full warranty.
- B grade: small cosmetic or electrical defects, such as scratches, colour differences, small micro-cracks or output below the label. Often sold cheaply, sometimes without the brand's warranty.
- C grade and below: larger defects. Should not be sold as normal panels.
Grades are not a formal government standard. They are the factory's own sorting, so a trustworthy seller and documents matter.
Why it matters in Pakistan
Pakistan imports most of its panels and the market grew very fast, so price pressure is high. ARY News reported warnings, including from LONGi, that B and C grade panels were being sold as A grade. A panel with micro-cracks may work well on day one and then lose output faster, especially with heat and the expansion of hot days and cool nights. You may not notice for months, until bills stop falling.
How lower-grade panels reach buyers
Factories sell panels that fail full checks as lower grades, often in bulk and without the brand's normal warranty. Some of this stock is relabelled or mixed with A-grade panels by traders further down the chain. Panels can also be damaged in shipping and storage, then sold on as new. Buyers rarely see the original packing list, so they depend on the seller's honesty and on the checks below. The cheapest offer in the market is where these panels most often appear.
Check 1: the label and serial number
Every genuine panel has a label on the back with the model number, power, voltage and current figures, and a serial number, often with a barcode or QR code.
- Check that the model on the label matches the invoice and the datasheet, for example JKM575N-72HL4 for a Jinko Tiger Neo 575W.
- Check that the serial number on the label matches the one on the frame or under the glass.
- Ask the seller for the serial list and verify serials with the maker or its local distributor where a check service is offered.
- Labels that look reprinted, stuck over another label or with spelling mistakes are a red flag.
Check 2: look at the panel
Before installation, look at each panel in daylight:
- Cells should be an even colour, without brown, white or snail-trail lines.
- No chips, scratches or bubbles under the glass.
- Frame corners tight, no bends.
- Junction box sealed, cables and connectors undamaged.
Micro-cracks are often invisible to the eye. An EL test shows them, so for large systems ask whether an EL or flash test report is available.
Check 3: test the output
On a clear day around noon, an installer can measure each panel's open-circuit voltage (Voc) and short-circuit current (Isc) and compare them with the label. In real sun the readings will be a bit below the label figures, but panels from the same batch should read close to each other. One panel far below the others points to a defect. After installation, the inverter app shows the string's power; compare it on clear days over the first weeks.
Check 4: price, invoice and paperwork
- Price: if a panel is far below the current market rate, ask why. Market trackers in 2026 put older P-type stock at about Rs 28 to 37 per watt, documented A-grade at about Rs 38 to 44 and premium N-type bifacial at about Rs 42 to 52 (Phoneworld, 2026). Prices move weekly, so treat these as a snapshot.
- Invoice: it should list brand, exact model, wattage, quantity and serial numbers.
- Warranty: ask who handles a claim in Pakistan and what proof is needed. Our warranty terms are on the Warranty page (Return & Refund Policy).
- Delivery: count the panels and check each box for damage before the delivery person leaves. Photograph any broken corner, dent or cracked glass, and report it the same day.
After installation: watch the numbers
Your inverter app is a free quality check. In the first weeks, note the peak power on clear days around noon and the daily units. A healthy array on a clear, cool day should reach a good share of its rated power, less in heat and haze. If one string reads much lower than another of the same size, or output keeps falling month by month after cleaning, ask for a check. Early proof, with dated screenshots, makes any warranty claim much easier, as explained in our warranty guide (Solar Warranty Guide for Pakistan).
Tier 1 is not the same as A grade
Tier 1 is a list made by BloombergNEF of makers judged bankable for large projects. It says nothing about a single panel's grade. A tier 1 brand can still produce B-grade panels at the end of the line, and those may reach the market. So a well-known name on the label is a good start, but you still need the checks above.
The reverse is also true: a smaller brand can make good A-grade panels. What protects you is the paperwork and the checks, not the logo alone. If a seller cannot tell you the exact model, show you the label, or explain who handles a warranty claim, look elsewhere.
What to ask any seller, including us
- Which exact panel model and wattage will be delivered?
- Can I see the serial numbers before installation?
- Is a flash test or EL report available for this batch?
- What does the invoice show, and who handles a warranty claim?
- What happens if a panel is damaged or below spec on delivery?
Our packages list the exact panel model (JinkoSolar Tiger Neo N-type 575W, JKM575N-72HL4) on every product page. Read about our 7-day checking warranty and terms on the Warranty page (Return & Refund Policy).
Verification by brand: Jinko, Longi and Canadian
Each big maker has its own way to confirm serials, usually through the official website or the authorised distributor. Never trust a QR code that opens a look-alike site. Our brand guides explain the steps for Jinko (Jinko Solar Panels Price in Pakistan (Tiger Neo 575W to 585W)), Longi (Longi Solar Panel Price in Pakistan: Hi-MO and X10 Models) and Canadian Solar verification (Canadian Solar Panels in Pakistan: Price, Models and Verification).
