• Worx@lemmynsfw.com
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    4 months ago

    We know this comment by Shannon Martin is correct and sensible because it was reviewed by Shannon Martin! As a licensed insurance agent, I’m sure she is qualified to talk about uh… electronics… hmm

    • frezik@midwest.social
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      4 months ago

      This is the sort of person who thinks you need to ground yourself to be safe while working with electricity. Not 100% wrong, but just wrong enough to be very, very dangerous.

      • Transporter Room 3@startrek.website
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        4 months ago

        Some people know just enough to be dangerous.

        For instance, an anecdote:

        A nearby local hardware store put up a sign in 2017 and now this year, in front of the welding equipment, that says “WELDING GOGGLES DO NOT PROTECT EYES AGAINST THE SUN”

        Now if they didn’t block uv from the sun, then they wouldn’t block uv from your welding arc.

        BUT I 100% stand by their choice to put the sign up.

        Because you need a certain shade or darker, and they sell a lot of different shades for different welding applications, including the safety tints people might want if they’re nearby and catch the occasional reflection.

        And some people know enough to know welding arc = UV, sun = uv, and don’t stop to think about intensity.

        In fact, in 2017, I knew someone who tried to use a #3 lense to look at the total eclipse, and as soon as the moon cleared moved enough for the sun to peek back, he deeply regretted not using a darker shade. Now has a weird spot in his vision that isn’t quite right.

        • DoomsdaySprocket@lemmy.ca
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          4 months ago

          A 3 is what my helmet gives me for grinding mode, that’s nothing.

          I used a 10 or 11 for one eclipse and it worked alright.

      • nilloc
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        4 months ago

        Just ground your left hand while you work on it with your right hand. That way if it’s live it’ll quickly stop your heart and you won’t even know you died. No half measures!

      • RobertoOberto@sh.itjust.works
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        4 months ago

        Working with small ESD-sensitive electronics and using a proper grounding strap and mat with large resistors in series to provide protection from shock? Absolutely.

        Wiring up a car battery or working with mains power? Absolutely not.

        • frezik@midwest.social
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          4 months ago

          Car battery on its own won’t kill you, though wiring many in series might. There can also be some effects from DC sparks and welding on even 12V, which might cause other problems.

  • MrEff@lemmy.world
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    4 months ago

    Looking passed the absolutely insane answer here, no one has even brought up the whole issue of AC vs DC. Batteries are DC, while your fridge that plugs into your wall running on AC. I know they make DC ones, but it isn’t like they are interchangeable.

    • themeatbridge@lemmy.world
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      4 months ago

      Funny thing, most modern refrigerators use DC motors for their compressors so that they can run at variable speeds, so there’s likely an inverter that you could bypass if you know the appropriate voltage. The DC ones for RVs are the same internals, just without the inverter.

      • nixcamic@lemmy.world
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        4 months ago

        Correction: they still use AC motors, but those motors don’t use line AC. It goes line AC > rectifier > DC > inverter board > variable frequency AC to run the compressor motor.

        Most RV fridges just use DC motors, but there are some that use VFDs and AC motors.

      • DreadPotato@sopuli.xyz
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        4 months ago

        Funny thing, most modern refrigerators use DC motors for their compressors so that they can run at variable speeds

        No they don’t…they use AC motors and a VFD to control the speed.

      • Jojo@lemm.ee
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        4 months ago

        I mean it’s probably labeled, right? How hard could it be?

        • themeatbridge@lemmy.world
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          4 months ago

          Exactly. Find a hole that’s black and a hole that’s red, and stick some wires in there. How hard could it be?

          • Jojo@lemm.ee
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            4 months ago

            (can’t answer, because she was fucking electrocuted)

    • tfw_no_toiletpaper@feddit.de
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      4 months ago

      There are DC-AC converters you can use (might be called inverters in English idk), which are pretty interesting circuits. They are used all the time, e.g. to use solar energy

    • ColeSloth
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      4 months ago

      That part just takes an inverter.

      I’m not sure of the max load output on a car battery, but with a 15 amp 1800 watt dc to ac inverter, you probably can run a fridge off one. It probably just won’t last all that long.

  • Naz@sh.itjust.works
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    4 months ago

    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.

    • baru@lemmy.world
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      4 months ago

      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.