As a point of reference, I have 2, 100 watt panels and before I changed to a 12V compressor refrigerator, they were just enough to replace the power that I used during a 24 hr period. Since I added the compressor refrigerator, I usually run a small deficit unless I have lots of sun. I am adding a 160 Watt panel to bring the total to 360 watts. So, I would say you will need at least 100watts to go 4 days, maybe more. If you have a lead acid battery, you don’t want to go below 50% (which I think is around 12.0 Volts)
Here’s a link to my solar install description: https://www.truckcamperadventure.com/forums/topic/my-solar-power-installation/
Joel
