Solar cooker reaches 180F in 1 hour

2 sunny days so I tried using solar cooker.
You can definitely feel the heat in the reflector funnel when I stuck my hand in. Even in a cool condition it heats up pretty good.

I could get the temperature up to 180F, but it didn't get past that. I used a small black pot with glass lid. Replacing the lid with black lid might improve a bit. I just used sweet potatoes sliced about 1/2 in thick. After 3 hours it got soft, but doesn't have that high heat cooking kind of puffed softness.

2nd day I tried using larger pot with more vegetables (sweet potatoes, winter squash, parsnip, beets) but the temperature stayed at around 150F. The lid was shiny silver. Reflecting too much light? Same set up as the day before. Winter squash was soft and good to eat, sweet potatoes got soft, but somewhat fibrous. Beet and parsnip were crunchy. Need more cooking.

On the original website, they say it gets up to 350F. How can I improve it?

I also noticed that the sun shade was thin and floppy. Perhaps I need to secure that a little better too. I'll try with a bit more rigid type too.

I will try to get some dutch oven and get the whole setup a little more sturdy.

After all it feels nice to just come home and meal ready. The cooking behavior can be changed. Prep for lunch and dinner can be all done in the morning or the day before and eliminate necessity to cook 3 meals.