If you put items in the fridge which are cooler than the air in the fridge it will reduce the compressor run time. The more dense the items the better.That's what I'm so confused about. Its definitely got ventilation at the moment as its pulled out. That does make sense with regards to things in it actually. I've put some beers out of fridge into it. I sort of hope it stays cold but I'm sure it's not going to. Your up early. Is it saturday in Aus now?
Putting items in which are warmer does the reverse.
Tip for an empty upright freezer is to put empty but sealed cardboard boxes inside, when you open the door you don‘t fill the freezer with warm air.
Battery monitors also consume power, just something to consider if the solar power budget is already low.