I have 4 100watt solar panels and 4deep cycle marine batteries. Will this run a mini fridge 24/7 or a chest freezer until I can upgrade my batteries?

It will depend on the Amp hour or reserve capacity rating of the battery (not cold cranking amps). An average battery will be somewhere around 100 Amp hours. A 1000 Watt draw will typically drain a 100 AH battery in approximately 1 hour without recharging. A fridge will typically turn on and off as it is needed and will not have a continuous load. Your best bet is to try it and alter your setup as needed with extra batteries. It would most likely power the mini fridge but not the chest freezer non stop.