• JohnEdwa@sopuli.xyz
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      3 months ago

      Watt hours are watt hours. Sure the compressor won’t run on 12 volts as is but the energy is there, just needs a converter.

      Fwiw, our 15 year old fridge uses around 1000Wh per day.

      • genie@lemmy.world
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        3 months ago

        Sure, buy an inverter and burn up 10% of your energy in the conversion if you’re lucky. That inverter will cost roughly as much as the contents of a standard fridge + freezer, by the way :)

        At that point just buy a well insulated cooler and always have some ice on hand. It’ll last much longer.

        • JohnEdwa@sopuli.xyz
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          3 months ago

          The question wasn’t “Is it efficient or cheap”, it was how much energy is in a battery, and if and for how long would it run a fridge. If you also want to add one more point to why you probably shouldn’t do it, car starter batteries don’t generally like to be deeply discharged, you’d want to get a marine battery for that use.
          As for how much the inverter would cost, depends on the fridge, but Amazon has a 1000W inverter for around $85, that should be enough for most. Ours could run from a 300W one, they cost around $30. Pretty handy devices if you want to run any kinds of electronics from a car anyway, I have one for when I want to charge my laptop and RC batteries on the field.

        • John_McMurray@lemmy.world
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          3 months ago

          3500 watt inverter is 300 dollars at a Flying J. Mines 7 years old and was used 5 years straight when I was a trucker, as I removed the 12v factory fridge that could kill 4 batteries over night, with a 110v fridge, I could safely leave food in all my days off and the truck would still start. Now it’s hardwired to my pickup as a emergency generator and electric impact wrench power source. People laugh initially when they me pull out the impact and then ask what it cost. I also mounted a coffee maker behind the seat because gas station coffee is fucking garbage and its 4 hours to a major center

      • genie@lemmy.world
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        3 months ago

        Congratulations, this is the worst attempt at ridicule I’ve ever seen

        • suodrazah@lemmy.world
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          3 months ago

          Your comment was ambiguous, stupid, and designed to ridicule. If you are attempting to imply inverter and other loss then be more specific. Regardless, the comment you were referring to already provides arbitrary values that you can assume include loss.

          So please explain to me what the fridge being 12v DC or mains AC powered has to do with anything, when an example uses arbitrary power and energy values? I’m genuinely curious.

          • genie@lemmy.world
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            3 months ago

            ooh getting aggressive now are we?

            I owe nothing to you. Enjoy your time being a sad person trying to bring others down on the internet :) I hope this little outlet makes you feel better

    • DogWater@lemmy.world
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      3 months ago

      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)