Can a portable battery safely run a mini fridge on a frequently tripping circuit?

Don’t assume the breaker is simply being dramatic. It’s a safety device, and repeated trips can indicate an overloaded, faulty, or otherwise unsafe circuit. A TV, game console, lights, and a fan normally shouldn’t overload a healthy circuit, so the landlord should have the wiring and breaker inspected. Don’t replace the breaker, bypass it, or use an extension-cord workaround yourself—especially in a rental. Also, a space heater draws far more power than a mini fridge, so the fridge might not trip the circuit by itself, but the underlying electrical issue still needs attention.

A $30 battery probably won’t do this. A mini fridge has a startup surge when its compressor turns on, and a battery unit would need an inverter rated for that surge as well as enough capacity to run it for the amount of time you want. Even modest portable power stations usually cost well over $100, and useful runtime can push the price into the several-hundred-dollar range. A small 12-volt refrigerator designed for vehicles or camping would be a better match than trying to run a regular AC mini fridge from a cheap battery pack.

A UPS or portable power station could run the fridge, but it would need enough continuous wattage, inverter capacity for the compressor’s startup surge, and a large enough battery for the desired runtime. Those requirements make it unrealistic at a $30 budget. A cooler that uses a frozen bottle, a thermoelectric cooler, or a purpose-built 12-volt camping fridge may be more affordable, although they won’t all provide the same cooling performance as a compressor mini fridge.