Does clear poly carbonate sheet magnify sunlight?

we used clear poly carbonate for a lid on a LDPE roto molded box. sitting outside in the sun it seems to act as a magnifying glass melting the surface below the sheet.

any ideas to help on this ?

Sand it to be rough. It might help deflect more light.



Probably just greenhouse effect causing the temperature inside to increase.

My EV charger with a clear polycarb cover overheats and turns off on sunny summer days for that reason.


unless there is a curve to the sheet, I don’t see why it would magnify the light. I do agree that the greenhouse effect is a more probable culprit.

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I’ll 3rd the “Greenhouse effect” comments. Polycarbonate is surprisingly effective as a thermal insulator, even without magnifying the light. Is there any way you can ventilate this box, or does it need to be “sealed”?

Also, polycarb absorbs UV light, which is eventually going to turn to heat (sunlight can degrade polycarb pretty quickly).

thanks everyone for the feedback. Unfortunately it needs to be sealed. I wish I could vent it.

If In really needs to live out in the sun, buy Aluminum foil tape, that’ll reflect most of the sunlight to minimize heat.