Guides · Faisalabad, Lahore, Punjab
Grade A vs Grade B Solar Panels: How to Tell the Difference
Short answer
A grade A solar panel has passed the factory's full electrical and visual checks; a grade B panel works but has a defect, cosmetic or electrical, and should be sold as B at a lower price. The risk in Pakistan is not that grade B exists, but that it is sold to you as grade A. You cannot reliably tell the grades apart by looking from the ground, so the answer is paperwork, a serial-number check, a close inspection on delivery and, for large orders, an EL test.
This guide goes deeper than our genuine solar panel guide, which covers each manufacturer's online serial check step by step. Here we focus on the grades themselves and how to catch a downgraded or refurbished solar plate before it goes on your roof.
What the grades actually mean
There is no single international standard for panel grades. Each manufacturer sets its own sorting rules, and IEC certificates test the design of a model, not the grade of the panel you receive. In practice the market uses the terms roughly like this:
| Grade | What it usually means | Typical issues | Who it is meant for |
|---|---|---|---|
| A | Passed all electrical and visual checks | None beyond tiny cosmetic tolerances | Normal retail and project supply |
| A- / "A minus" | Electrically fine, very minor cosmetic marks | Slight colour difference, small scratch on the frame | Sold openly at a small discount by some makers |
| B | Works, but has a visible or measurable defect | Colour patches, small cell chips, lamination marks, lower measured power than the label class | Sold as B, usually with reduced or no warranty |
| C and below | Electrical output out of specification | Cracked or broken cells, failed tests | Scrap or very low-cost markets; should never reach a home roof |
| Refurbished | Previously installed or damaged, then cleaned and relabelled | Unknown history, hidden micro-cracks, re-sealed junction box | Sold as used, or dishonestly as new |
Grade definitions vary between factories. Ask for the grade in writing rather than assuming what a label means.
The key line is between A and everything else. A grade B panel is not necessarily dangerous on day one, but it is more likely to develop hot spots, cracks or snail trails over time, and the manufacturer's warranty may be reduced or absent.
Grade A vs grade B panels
Grade A
New, tested, with manufacturer's warranty
Grade B
Cosmetic or performance defects, weak warranty
How grade B and refurbished panels reach the market
Lower-grade stock is a normal by-product of any factory. It becomes a problem through relabelling and mixing:
- Relabelling. Grade B panels are given new stickers showing a grade A model or a higher wattage class.
- Mixing in lots. A pallet is mostly grade A with a few B panels placed in the middle, where buyers rarely check.
- "Same brand, any wattage." A seller offers one brand in many power classes at a discount, which often means mixed stock from several sources.
- Refurbished as new. Panels removed from damaged or upgraded sites are cleaned, given new labels and sold as fresh stock.
- Ship-to mismatch. Genuine panels made for another market are resold here, where the manufacturer's warranty may not apply.
For used panels sold openly as used, see our separate guide to used solar panels and inverters.
Six ways to tell grade A from grade B
1. The grade is written on the quotation and invoice
Your quotation should name the brand, exact model, wattage, quantity and the words "grade A, new". If a seller will not put the grade in writing, treat that as the answer. Our quotation comparison guide shows what else a proper BOQ should include.
2. The online serial check shows the grade
Some manufacturers' online checks return the module grade along with the model, power and ship-to country. Check panels from different cartons on the maker's own website, never through a link from the seller. Steps by brand are in our genuine panel guide.
3. The labels agree with each other and the datasheet
The serial number on the front barcode strip, the back nameplate and the carton label should match. The electrical ratings on the label should match the manufacturer's datasheet for that model. Our guide to reading a solar panel datasheet explains which numbers to compare.
4. A close look in daylight
Inspect each panel on delivery, before it goes up. Signs of a lower grade or refurbished panel:
- cells of noticeably different colour, or patchy discolouration;
- chipped cell corners, visible lines or "snail trails" across cells;
- bubbles, white marks or wrinkles in the lamination;
- scratches through the glass coating, or a back sheet that looks yellow;
- a junction box that has been opened, re-glued or shows heat marks;
- cables that are cut, re-crimped or have mismatched connectors;
- a second label stuck over an older one.
5. Electrical test in sunlight
A qualified technician can measure each panel's open-circuit voltage and short-circuit current in good sunlight and compare them with the datasheet. A grade B panel may read noticeably below others in the same batch. Panels in sunlight produce dangerous DC voltage, so this is not a do-it-yourself test.
6. EL imaging for large orders
Electroluminescence (EL) imaging shows micro-cracks and dead cell areas that are invisible to the eye.
Grade A vs grade B at a glance
| Check | Grade A, new | Grade B or refurbished |
|---|---|---|
| Grade written on invoice | Yes, without hesitation | Avoided or vague |
| Online serial result | Matches model, power and grade | Not found, wrong model, wrong grade or high query count |
| Labels | Consistent front, back and carton | Mismatched or over-stickered |
| Appearance | Even colour, clean lamination | Patches, chips, marks, re-sealed box |
| Measured output | In line with batch and datasheet | Lower than others in the batch |
| Manufacturer warranty | Per product, in writing | Reduced, refused or unclear |
| Price | Close to the market rate for that model | Well below the market rate |
The price trap
A grade B panel is cheaper to make and buy, so a price well below the market rate for the same model is the most common warning sign. Compare quotes on a per-watt basis for the same brand and model, using our price per watt guide, and check today's rates on our solar panel price page.
Remember what you are buying. Panels run for decades. A small saving per panel at purchase can be lost many times over through lower output and a warranty claim the manufacturer rejects. Our warranty guide explains how product and performance warranties work.
How Solar Works Pakistan supplies panels
Solar Works Pakistan supplies new panels from LONGi, JinkoSolar, Canadian Solar, JA Solar, AIKO, Cora Dawn and Jasco, sourced through established Pakistani distributors. See the brands we supply. Our quotations name the brand, model, wattage and quantity, and the manufacturer's warranty for each product.
Our own teams handle installation, testing and commissioning. You are welcome to check serial numbers on the manufacturer's site before and after delivery.
Get today's price or a free site survey
Want a quote that names the exact panel model and grade in writing?
- WhatsApp or call: 0336 666 4321
- Email: info@solarworks.pk
- Head office: Main Boulevard, Sargodha Rd, Block F FDA City, Faisalabad
- Lahore branch: 2nd Floor, Jeff Heights, Gulberg, Lahore
- Hours: 9:00 AM to 6:00 PM daily
We serve customers throughout Punjab, from about 6 kW homes to megawatt-scale plants. Site surveys are normally free. You can also use our contact page.
Frequently asked questions
What is the difference between grade A and grade B solar panels?
Grade A panels pass the factory's full electrical and visual checks. Grade B panels work but have a defect, such as colour patches, small chips or lower measured power. Grade B should be sold openly as B at a lower price, often with a reduced warranty.
Are grade B solar panels bad?
Not always dangerous, but they carry more risk. Defects can grow into hot spots or cracks, output may be lower, and the manufacturer's warranty may be limited. The bigger problem is grade B sold as grade A at an A price.
Can I see the grade on the panel label?
Usually not. The label shows the model and electrical ratings, not the grade. Ask for the grade in writing on the invoice, and use the manufacturer's online serial check, which for some brands shows the grade.
How do I spot a refurbished solar panel?
Look for scratched glass or frames, a re-sealed or re-glued junction box, cut or re-crimped cables, a yellowed back sheet and labels stuck over older labels. A serial number that has been checked many times online is another warning sign.
What is an EL test?
Electroluminescence imaging passes current through the panel in the dark and photographs the glow from the cells. Cracks and dead areas show up as dark lines or patches. It is the most reliable way to find hidden damage in a large order.
Is "Tier 1" the same as grade A?
No. Tier 1 is a financial list of manufacturers, not a quality grade for an individual panel. A Tier 1 brand can still produce grade B stock. See our genuine panel guide for more.
Does Solar Works Pakistan sell grade B panels?
We quote new panels from the brands we supply, with the brand, model and manufacturer's warranty named in writing. Ask us to show the grade on your quotation.
Sources
- Sinovoltaics, "Solar cell grading (A, B, C, D)"
- Sinovoltaics, "Grade B solar cells: how PV buyers are cheated": https://sinovoltaics.com/quality-control/grade-b-solar-cells-no-1-trick-how-pv-buyers-are-cheated