My current means of powering things is USB rechargable batteries. I have a about five of them that range between small 3000-5000mah ones to a big 20000mah interstate battery jump starter pack. Is there a device that lets me add all their power together into a centeral power source so I don’t have to keep swapping them out?

  • testfactor@lemmy.world
    link
    fedilink
    arrow-up
    1
    arrow-down
    14
    ·
    1 year ago

    Or, I mean, it could just wire all the positives together and all the negatives together and hook that right into your target device.

    It’d be the same output voltage regardless. A little less internal resistance, and lower step down in the later phases, but neither should make a difference in what you’re powering.

    Kinda like how there were those converters for the GameBoy back in the day that let you put C batteries into it. Same principle.

    • Zak@lemmy.world
      link
      fedilink
      arrow-up
      17
      ·
      1 year ago

      It’s probably not possible to do that safely because USB power supplies aren’t just dumb batteries. They actively communicate with the device receiving power about how much current the device wants, and should only supply 500mA if they fail to do so.

      USB-A ports aren’t supposed to receive input power, which is effectively what would happen in that arrangement after a powerbank shuts off to prevent over-discharge of its batteries. The resulting behavior is, as I recall unspecified and might result in damage to the powerbank. Worse, it could interfere with the over-discharge protection and damage the batteries. Charging damaged Li-ion batteries is bad, where bad may include fire, explosion, and/or emission of toxic gas.

      • testfactor@lemmy.world
        link
        fedilink
        arrow-up
        5
        ·
        1 year ago

        Yeah, I should work on my reading comprehension.

        I deff read the prompt as having a bunch of rechargeable AA style Li-ion batteries, and how to utilize them without having to swap out to a new pair or whatever.

        Deff don’t want to do this with a bunch of disparately sized smart batteries providing power over USB. Very different problem.

    • Smokeydope@lemmy.worldOP
      link
      fedilink
      English
      arrow-up
      1
      arrow-down
      2
      ·
      1 year ago

      So I could actually get a couple of old short usb cords together cut the ends off, strip the positive and negative wires and hook them in series without it changing the output voltage?

      • sarchar@programming.dev
        link
        fedilink
        English
        arrow-up
        9
        ·
        1 year ago

        No…please do not do this.

        The voltages of the output ports are probably not all exactly the same and you could end up damaging the device (or worse, starting a fire). They MIGHT have reverse current protection on them, but I’ve seen some pretty sketchy power banks.

        You can’t just wire them in parallel. USB has communication pins that help boost circuits in the battery change voltages levels. Even if it all works, you’re going to get extremely poor charge times.

        I don’t believe it’s out of the realm of EE to design something that allows you to plug in multiple power banks though, but I’ve never seen any