We once had some friends give us several boxes of very ripe black cherries–my very favorite berry! Problem was that they were already starting to go bad and we had to do something with them QUICK. So Nick rigged up a temporary solar dehydrator out of supplies that we had here laying around. 3 cement blocks, a few lengths of 2X4’s, a piece of metal roofing, a fan, and an old piece of glass window pane.
While he set it up, I quickly sorted out the good cherries, cleaned and pitted them, and spread them out on some cookie sheets that I had in the kitchen. Then we put them under the glass supported by the the 2X4’s and complete with my new oven thermometer we left it in the sun to see how it would work. At night I would bring them back into the house and in the fridge so they wouldn’t go bad, but after the first night, I left them out even at night till they were dry. During the day while the sun was shinning the temp was 150 degrees F inside the dehydrator.
At the end of 4 days those cherries were a little too dry! And I had a whole quart and a half of dried cherries! They tasted really delicious on top of our cereal the next morning. I also dried comfrey root out in the sun, however I didn’t need to put those inside under the glass. They dried rather quickly just out in the open on baking sheets.
http://www.sustainablepreparedness.com/index.php/blog/dried-fruit-in-a-solar-dehydrator
I have used a screen and put it in my truck with the windows down 1-2inches. Works good and your car smells like plums and strawberries.