Strange crud on new panels - ok to use ?

[meetyg]

I just received 4 x 100w DOKIO rigid (glass) panels.
I know that DOKIO is not one of the bigger/well known PV manufacturers from China (as opposed to Longi/Trina/JA etc..), but I got a good deal on them on Aliexpress (11.11 sale) for $106 Shipping included.

But I do know that many are happy with their foldable/portable panels, so I decided to give them a chance. I needed specific dimensions (replacing existing flexible panels) and these were exactly what I needed.

Anyways, unboxing and inspecting them, I noticed some weird marks on two of the 4 panels.
One has some strange brownish crud (maybe rust/ corrosion?) between the glass and the cells at two spots, and what looks like some plastic debris.

The other panel has some weird marks on it, and some brown spots (maybe finger prints?).

Other 2 panels look spotless.

I might be over reacting here, but I'm worried about long term use of the panels, including possibility of hot spots, degradation, etc...
I tried cleaning them, but the spots are under the glass, so it's not surface dirt...

What do you think?
Am I too pedantic, or are my worries true?


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[meetyg]

Any thoughts?
I'm currently requesting a partial refund from the seller. He's asking me to test the panels.
My concerns are not about power output currently, but more long term longevity of the panels and formation of hot-spots and/or quick degradation of the specific cells.

 

[RCinFLA]

From pictures it looks like inconstancies in the adhesive layer between actual cells and front glass.

Usually during assembly, panels are exposed to vacuum to remove micro bubbles in adhesive used to bond cells to inside of front glass and pull cells to inside front of glass with minimum adhesive thickness between cell and glass.

If adhesive is mixed too aggressively it becomes whipped cream that is difficult to remove all the micro bubbles. They coagulate to larger area before adhesive finally cures.

 

[HRTKD]

Looks sketchy to me. I bought some used panels that had surface marks. I polished out the marks using automotive polish and they look pretty good now and perform well enough that I'm satisfied. But all the marks were on the surface of the glass. A couple of those pictures look like a flaw between the glass and the cell.

Testing the panels is the least you can do.

 

[meetyg]

Yeah, that's between the glass.
Later on I also found some shipping damage on one of the panels, and frame was a bit loose:


So I contacted the seller again.
They offered to send a replacement panel instead of dispute and partial refund.

I hope that they aren't trying to scam me.

I'll keep you posted.
Thanks for the replies.

I guess you get what you pay for, but really didn't have much choice. Sourcing panels locally is twice as expensive.

Some 100w Renogy or HQST would have met the dimensions I needed, but Amazon doesn't want to send them to my region, unfortunately.

 

[HRTKD]

Sourcing 100 watt panels locally is expensive. Because what is stocked locally is usually for commercial/Residential professional installation. I saved quite a bit buying 320 watt panels locally.

 

[meetyg]

I needed these 100w for their size, replacing 100w flexible panels on my pergola "wing".


The flexibles are pretty poor in performance.
I'm getting only 180w at peak, from 4 x 100w flexibles. They are more like 50w each...

 

[meetyg]

Sourcing 100 watt panels locally is expensive. Because what is stocked locally is usually for commercial/Residential professional installation. I saved quite a bit buying 320 watt panels locally.

Other then thepergola "wing panels", I also have 2x 455w half-cut mono panels on the pergola itself.
These perform nicely, but only catch the noon sun, as they are on around 10-15 degrees angle, facing East (like the pergola).

The wing panels catch the earlier morning sun (also facing east).

 

[curiouscarbon]

thanks for documenting your experience ?