• IrateAnteater@sh.itjust.works
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    4 days ago

    How are joules less confusing for the purpose of battery life? I’ve heard of exactly zero devices ever that give their energy consumption in joules. I do however, know how to find the power draw of a given device in amps, and then I can very easily estimate how long I can run that device for if I know the battery capacity in amp-hours.

    • Grail@multiverse.soulism.netOP
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      4 days ago

      A watt is one joule per second. So if a phone consumes 100 watts, and its battery has 1000 Joules, it’ll run for ten seconds. If its battery has 8 megajoules (which is as much as an average person eats in a day), it’ll run for eight thousand seconds. Which is about 2 hours. It’s easy and simple.

      I understand watts. I don’t really understand amps. I know how many watts My PC draws because I installed the power supply Myself. I don’t know how many amps it draws. I don’t know how many amps My phone draws, or My wireless mouse, or My body.

      My phone’s battery lasts longer when I turn the screen brightness down. Does that mean the screen is drawing a variable number of amps depending on the brightness? That’s confusing! I don’t really understand what an amp is, so I can’t visualise that. I can understand the fact that a dark screen draws less watts easy, because watts are just energy per second.

      • real_squids@sopuli.xyz
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        4 days ago

        I know how many watts My PC draws because I installed the power supply Myself.

        You know what it’s rated for, but actual usage varies constantly. Open up your gpu overlay and it will show you the biggest users (aka your cpu and gpu).

        You can install an app right now and see your phone’s battery draw in mA so you don’t even have to convert anything.

      • MentalEdge@sopuli.xyz
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        4 days ago

        Then why joules?

        Watthours is another already fairly common unit.

        1Wh lasts for one hour at one watt. Half and hour at two watts. And so on.

        Amps are directly related. You can get the amps from the wattage, by dividing the watt with the voltage being run.

        • Grail@multiverse.soulism.netOP
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          4 days ago

          Watthours are stupid. You’re taking the SI unit of energy, the joule, dividing it by time to get watts, and then multiplying it by a different unit of time to get energy at a different conversion rate. It’s ludicrous! I have a philosophical opposition to such confusing units.