Great question! The 1.6kWh pack will run your fridge for about 32 hours. We designed an “Expansion Pack” that doubles the battery to 3.2kWh and gives 2x 60V MPPT solar inputs (for up to 1200W of direct PV charging). But of course “your mileage will vary” depending on your fridge’s size. That’s where the real-time backup time remaining forecast comes in handy!

Answering my own question here - 1.8kWh / 500-ish Wh/day for fridge usage is 3-4 days.