Can a cooler with a battery pack replace a fridge for camping trips?

Yes, but only for short trips and with the right gear. A passive cooler with a battery pack just keeps ice frozen longer, not actively cool. An active cooler (thermoelectric or compressor) plugged into a battery pack can hold food at safe temps for hours, but thermoelectric ones drain a 100Ah battery in 8–12 hours and struggle in heat. For a day trip it’s fine, but for multi-day trips, bring backup ice or a generator.