Hello, expert solarpunk here.

**TLDR: Car battery is 350Wh. Fridge uses 143W idle, so it’ll run a fridge for 2-3 hours. **

Explanation below:

Car batteries are lead-acid (sulphuric acid and lead plates).

They discharge according to Peukert’s Law as the negatively charged plate gets covered in lead via the acid (electrolyte).

As the battery depletes, the negative plate can begin to take permanent damage, and so you can’t discharge a lead-acid deeper than 10-20%, or about 10.8V, with the safe limit being ~50% discharge.

Most 12V, 60Ah batteries therefore only safely store and nominally discharge 350 Wh @ 350W.

You can discharge that as fast as you want but the faster you discharge, the lower the capacity is (with 1000-1500W bringing you way down to like 65 Wh). Fridges have a surge when they start up to fire up the compressor. Starter batteries can take that, but once the refrigerant is cold, the fridge just maintains the temperature which uses a lot less energy - about 143W on average.

Fridge uses 143W idle

Isn’t that like 1250 kWh on an annual basis of idle usage? An efficient fridge should use 150-200 kWh per year, this isn’t just idle usage. Even an inefficient fridge would be really high with that kind of idle usage.

Also assumes that the average fridge runs on 12V 😂

No it doesn’t. Watts do give a shit what percentage is voltage vs amps. You have to convert between AC and DC as appropriate as well as ensuring the voltage of a 12v battery is stepped if needed, but the watts are the same in any case. (Not figuring for system losses)

This argument is equivalent to saying you can run a fridge off of gravitational potential. Sure, energy is energy. That doesn’t make it remotely practical for the average person to use that form of stored energy, you absolute wet paper bag of an overly confrontational putz.

You should Google what a step up and step down transformer do. It’s very simple and easy to prove you’re a dipshit once you understand you’re arguing from bad faith trying to compare a simple bit of circuitry design to hydro power.

Go ahead and prove it then :) if it’s so very simple and easy