If you don't want a generator, this is a great backup. It's great for any other uses when you need high power in remote areas, but it's also nice to have in a power outage. If you're sitting in your car charging your phone, you can pop the hood and attach this to your battery for an outlet with 1000 watts which should be able to power a small fridge/freezer. I use it quite often as I often need to power some power tools where I don't have an outlet and much easier than lugging around a portable generator.
https://www.homedepot.com/p/DEWALT-1000-Watt-Portable-Car-Power-Inverter-with-Triple-USB-Ports-DXAEPI1000/301887060?MERCH=REC-_-searchViewed-_-NA-_-301887060-_-N