Just remember you should not over drain the batteries. 2 x 200 amp/h bats will give you just 80amp/h at the reccomemnded 20% DOD (depth of discharge) to give you the max battery life. Going to 50% DOD will half the bat life, going to 80% DOD will reduce batt life to a fraction of the 20% DOD time.
That 80amp/h will give you 960watts. How many watts is the 12v fridge? Divide the 960w by the about a 1/3rd of the fridge watts (as it wont be drawing power all the time).
Fully charged bats read 12.6v
discharge by 20% & the will read about 12.3v
discharge by 40% & the will read about 12.2v
discharge by 60% & the will read about 11.9v
discharge by 80% & the will read about 11.6v
discharge by 100% & the will read about 10.6v
So you can see that the inverter cut off points set normaly at 10.5v is far to low.
300w of solar panel “should” give you upto 1380 watts during the height of summer but only 3-400 watts in winter. (in the UK)