Solar panel with circuit inside a PC box -Not working

  • #1
Madhumkm12
2
0
TL;DR Summary
Solar panel and circuit not working as intended inside a Polycarbonate box.
Hi,
I am trying to build a product where i am placing a solar panel along with a driver board inside a Polycarbonate housing and closing it with a ABS cover at the back.
The driver board is soldered at the back of the solar panel and placed inside the PC box. Then a RTV(silicone sealant for leds ) layer is applied to hold still the setup inside the PC box. Then a 2 potting component is mixed and poured to make it waterproof IP68.

Here comes the problem. The panel is generating around 300mah when the panel board and the battery is outside in open air and the battery goes from 2.9v to 4v. But when the same setup is placed inside the PC box and kept for testing the battery is not getting charged. Still the solar panel generates the same 300mah current inside the box as well.

The doubt is whether the driver board is acting weird inside the PC case as the temperature inside the box is around 60'C and since the back is also covered there is a hot air inside thats not circulating. So some thermal reaction is happening.
How to over come this situation. There is no way i can make an air vent or Heat sink because in order to achieve IP68 i need to seal with potting.

Please help me out with a solution on this or the way it has to be approached
 
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  • #2
Welcome to PF.

Can you post some pictures? (Use the "Attach files" link below the Edit window.)

Also, can you consider a metal enclosure and thermally conductive epoxy to help get the heat out of the enclosure?
 
  • #3
There is no possibility to go for a metal enclosure as we are putting LED to light up at night. so need a transparent material so only chose PC. which allows 88% of light inside. Tested on that.
we use Potting which is thermally conductive only so that it doesn't allow external heat inside and absorb from the panel or driver board as well.

Before doing this we try to test in once before pouring potting. But now there is an anomaly caused because of this charging issue
 

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  • #4
Madhumkm12 said:
The doubt is whether the driver board is acting weird inside the PC case as the temperature inside the box is around 60'C and since the back is also covered there is a hot air inside thats not circulating. So some thermal reaction is happening.
The battery has three wires so it's likely with a thermistor, which is monitored by the controller board. It'll stop charging if the temperature is too high.
The controller will likely monitor its own temperature too and shut down if it is too high.
Though it should still charge periodically. Just not full time. You should be able to check that.

Since it's just the normal operation I guess the only thing you can do is to remove the heat and maintain stable temperature (for both the battery and the controller).
Maybe you can add some copper plates below the potting. But this will require some engineering...
 
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