Painting over sylgard?

[glock15]

I am planning on building two panels into a suitcase set up for charging my RV batteries. my frame will be built out of aluminum channel and the back will be covered with aluminum deck plate, using a plexi front and encapsulating with sylgard. after the sylgard cures I was considering painting the back side of the panel (over the sylgard)and then using spray in foam insulation to fill athe void area between the panel and the deck plate back. has anyone tried painting over slygard? the reason for the paint is so the spray in foam is not directly exposed to sun light.

[Mike90250]

What's the foam for ? The more heat retained by the panels, the less power they will put out.

[glock15]

the reason for the foam would be to help stabalize the panel and assist in holding it in place. this setup will see some rough roads in the back of my truck.
I thought that if I could paint the back a light color it may assist in the retention of heat.

[glock15]

when you loose power due to excess heat is in the form of voltage or amperage or is it both. the voltage im not so worried about because like most my panel is 18+ volts in strong sun (hot part of the day) and that voltage is regulated down to 14.5. so in the heat of the day im not making full use of available voltage. the current I would like to try to maintain but if I drop a half a amp im not worried the panel is still sufficient for my application.

[Mike90250]

As heat goes up, the voltage goes down. So, you would loose final charge capability, as the later part of the charge cycle is voltage dependent, needing 15V or so. And you loose a bit in the charge controllers too, so 18V is good for average panels, but hot running ones, will output a little less.
Tough choice.

[glock15]

ok looks like no one has tried to paint over sylgard, how about putting a backing material over it while it is still wet? I want to come up with a thin option light in color so I dont have sunlight shining through the panel.

[Mike90250]

anything that aborbs light, will add to the heat load of the panel, lowering your watt output

[glock15]

I recognize that I need to use as light colored a material as possible, and I am concerned about heat retention but my application is a bit different than most. In that my panel will see very limited use a year, and when it is used it will be in the mountain areas of Utah or Utah’s desert in the cool months. I am building it with an enclosed aluminum back and I am trying to find a backing to keep light from traveling through the front glass and then having it reflect back creating an oven effect

[labbie48]

Paint will not adhere to Slygard. I've tried it and it doesn't work.