Comment on Coin-sized nuclear 3V battery with 50-year lifespan enters mass production

• Blue_Morpho@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

  Google says a Casio watch needs .004mA so not quite enough.

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  • dnick@sh.itjust.works ⁨3⁩ ⁨weeks⁩ ago

    Did you typo or did he? .03 is significantly bigger than .004

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  • libra00@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

    0.03 is 7.5x more than 0.004 tho?

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    • Blue_Morpho@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

      You are right! I didn’t count the 0’s!

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  • sugar_in_your_tea@sh.itjust.works ⁨3⁩ ⁨weeks⁩ ago

    That’s definitely in the ballpark though. Surely they could for 25% power draw to support a 50 year battery.

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  • mesamunefire@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

    I wonder how much we really need for a clock (555 eq) to work?

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    • piecat@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

      www.ti.com/lit/gpn/LM555

      2mA minimum, and that’s just q current. It’s gonna be much higher when you’re actually using it for a clock.

      I’m sure the casio’s main power sink is the display. I bet the refresh rate could be reduced for better battery life.

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      • Tangent5280@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

        Isnt the refresh rate just 1 Hz?

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    • cubism_pitta@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

      A lot more than that. 2ma

      Smaller packages may be more efficient.

      Analog circuits are weird though

      www.ti.com/lit/ds/symlink/ne555.pdf

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• ExcessShiv@lemmy.dbzer0.com ⁨3⁩ ⁨weeks⁩ ago

  Not really actually…

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  • sugar_in_your_tea@sh.itjust.works ⁨3⁩ ⁨weeks⁩ ago

    Why not?

    A CR2032 has 235 mAh, which I believe Casio watches use, and their batteries last 5-7 years. So, if we divide that out, that’s something like 5-6 microamps (235 mAh / 5 years / 365 years / 24 hours * 1000 = 5.36… microamps). Converting this to watts @ 3v: 15-18 microwatts.

    I think that math is correct (this question reaches a similar conclusion), and it leaves some headroom as well.

    If you remove RF from the equation (Bluetooth, WiFi, etc), you can get some very low power draws. If all you’re doing is sampling temps or something, you could send an update periodically over serial or something and fit under 100microwatts or so. You could probably even do RF if you have a large enough cap and send once it charges.

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    • ExcessShiv@lemmy.dbzer0.com ⁨3⁩ ⁨weeks⁩ ago

      CR2032s are used in many things that require significantly more power than that, and this cell is absolutely unfit for almost all other uses than barebones old school digital watches.

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      • sugar_in_your_tea@sh.itjust.works ⁨3⁩ ⁨weeks⁩ ago

        Sure. I’m not saying it’s a drop-in replacement, just that it has a number of applications. A simple digital watch or even a bare bones IOT device (with periodic serial signaling) could work well with it. You’d essentially set it up once and you’ll forget it’s still there many years later.

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  • cubism_pitta@lemmy.world ⁨3⁩ ⁨weeks⁩ ago

    Cell != Battery

    Battery = MANY Cells

    I am not correcting you just hate the headline.

    If you made a battery with 666(667 if we round up) of these you could supply 2ma of power at 3v for 50 years!

    I don’t have sizes available so assuming 2032 sized batteries… If you stacked them that would be over 2meters tall.

    With further advancement these could be viable

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