Buying Solar
How to buy solar in Karachi: genuine panels, invoices, warranties and used equipment.
Buying solar in Karachi · Used panels
Used Solar Panels in Karachi
A used panel can save money. It can also hide cracks, lost output and a warranty that no longer applies. Here is how to judge one.
- ✓ Faults to look for
- ✓ Tests you can run
- ✓ When used makes sense
Why people look at used panels
A used panel costs less per watt than a new one, and the saving tempts buyers when the budget is tight. Used panels come from replaced systems, from clearance stock and from projects that were cancelled.
Our quotes are for new equipment with warranty papers. This page is general guidance, so that you know what you are looking at if someone offers you a second-hand panel.
Sher Shah is described on Wikipedia as a hub for scrap and used parts, which shows how large the trade in second-hand goods is in Karachi. Whether a used solar panel from any seller is sound is something you must check for yourself.
Faults a used panel can hide
Many of these are invisible from a few steps away.
| Fault | What causes it | What it does |
|---|---|---|
| Micro-cracks | Handling, hail, uneven mounting, a drop | Cells lose output, often more over time |
| Hot spots | A damaged cell or bad solder | Local heating and lost power |
| Delamination | Age, heat, moisture | Water enters and corrodes the cells |
| Backsheet damage | Sun, heat, rough storage | Insulation loss and a safety risk |
| Junction box faults | Heat, moisture | Open circuits and burnt contacts |
| Degradation | Years of sun | Less power than the label says |
How to test a used panel
No test is perfect, but together they catch the worst ones.
- 1
Look at it closely
Check the glass, the frame, the backsheet and the junction box in daylight. Tilt the panel and look for cracks, browning or bubbles.
- 2
Read the label
Find the model code, the rated watts and the date of manufacture. Check them against the maker's datasheet.
- 3
Measure open-circuit voltage
In sun, a multimeter should read close to the label's Voc. A low reading points to a damaged cell or bypass diode.
- 4
Measure short-circuit current
Most hand meters cannot safely measure the short-circuit current of a large panel, so use a tester made for the job. Compare Isc with the label and the sunlight. Low current means cell damage or heavy soiling.
- 5
Ask for an I-V curve or flash test
A trader with a curve tracer can show the real output. Without it you are guessing.
- 6
Look at it with a thermal camera
Hot spots show up under load. This is the best check, and few sellers can do it.
What the price should reflect
A used panel should cost clearly less per watt than a new one, because you take on three risks: lower real output, a shorter life and no warranty. How much less is a matter of the test results and the age. There is no fixed discount.
Do the sum on the real output. If a panel is labelled 400 W but tests at 340 W, you pay for 400 and get 340. Divide the price by the tested watts to compare with new panels. Our price per watt guide shows the method.
Do not mix used with new
Panels in one string should match in current and voltage. A used panel with lower current pulls the whole string down to its level, so a new panel beside it works below its rating. If you buy used, buy a matched set, and do not add to an existing array.
When used might make sense
A used panel can suit a small off-grid job, such as a pump, a gate light or a shed, where output loss matters little and failure is cheap. A matched batch with test sheets is far safer than a single panel with a story.
For a home system you rely on, or one connected to the grid, new panels with a warranty are the better choice. The price gap is smaller than the cost of a failure on the roof.
FAQs
Questions people ask us
Short answers. For your own property, send us your electricity bill and roof details.
Ask on WhatsAppOnly for small, low-risk jobs, and only with test results. For a home system, new panels with a warranty are safer.
Inspect it in daylight, compare label and datasheet, measure Voc and Isc in sun, and ask for an I-V curve or thermal check.
Usually not, or the original warranty no longer applies. Ask for it in writing.
Cheaper per tested watt than new, enough to cover lower output, shorter life and no warranty.
Our quotes are for new equipment with warranty papers. Ask us if you want a new-panel quote to compare against a used offer.
Related pages
Solar Markets in Karachi
What to check when buying solar equipment from an open market in Karachi.
Mono vs Poly
Monocrystalline versus polycrystalline panels, and what to choose now.
Price Per Watt
How to work out price per watt and compare solar panel quotes fairly.
Weighing new against used?
Tell us your budget and the job. We will quote new panels with warranty papers so you can compare. The estimate is free.