Autoelectric Switch Off

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This topic contains 15 replies, has 3 voices, and was last updated by  Kyuuketsuki 1 year, 5 months ago.

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  • Kyuuketsuki
    Participant
    #167052

    So,

    I have an odd query :)

    My PC can take a minute or more to shutdown (more when patching) and mostly I want it instantly off. Unlike a laptop (on battery), I can’t just shut it down and leave it so I have to wait until the lights go out and then switch off at the mains. I know many people don’t do this but I do … I’ve checked and a PC tower system like mine uses 40W even when switched off i.e. like many modern devices they are never truly off.

    So I am looking for a power switch that I can switch off immediately but will continue to provide power for, maybe, five minutes or maybe even auto senses the load and when it drops under a pre-specified level cut it completely.

    Does anyone know of such a thing?

    Keke


    Ossian
    Moderator
    #191684

    A small UPS, combined with software to shut down the PC on power failure. Switch off the power to the UPS, and let the battery run down. The software will kick in and shut down the PC (hopefully before the battery gives up)


    Kyuuketsuki
    Participant
    #312517
    Ossian;n511009 wrote:
    A small UPS, combined with software to shut down the PC on power failure. Switch off the power to the UPS, and let the battery run down. The software will kick in and shut down the PC (hopefully before the battery gives up)

    Now that’s a good idea … you, Sir, are a foot (a “leg end”) ;)

    Keke


    JeremyW
    Moderator
    #271491

    I don’t think the UPS option would be good. UPSes are usually rated for only 2 – 3 deep discharges per year. In this setup you would be doing a deep discharge every day (unless you spec out a large enough UPS that it can supply power the whole time it’s off and only do a shallow discharge… but that would defeat the point). I think you’d find this would only last a few weeks.

    Do you have remote access? You could use an IP based switch and just remotely turn off the power… https://www.google.com/search?q=ip+power+switch


    Kyuuketsuki
    Participant
    #312518
    JeremyW;n511018 wrote:
    I don’t think the UPS option would be good. UPSes are usually rated for only 2 – 3 deep discharges per year. In this setup you would be doing a deep discharge every day (unless you spec out a large enough UPS that it can supply power the whole time it’s off and only do a shallow discharge… but that would defeat the point). I think you’d find this would only last a few weeks.

    Oh!

    JeremyW;n511018 wrote:
    Do you have remote access? You could use an IP based switch and just remotely turn off the power… https://www.google.com/search?q=ip+power+switch

    Potentially but that solution looks expensive and I’m a bit broke :(

    Keke


    Ossian
    Moderator
    #191687

    Surely the shutdown software would kick in well before the UPS got into deep discharge?
    I agree letting the UPS run completely down would not be a good thing, but if the UPS offers say 20 minutes, but the shutdown takes 3-4 minutes, you are talking about less than 20% discharge


    JeremyW
    Moderator
    #271492
    Ossian;n511030 wrote:
    Surely the shutdown software would kick in well before the UPS got into deep discharge?
    I agree letting the UPS run completely down would not be a good thing, but if the UPS offers say 20 minutes, but the shutdown takes 3-4 minutes, you are talking about less than 20% discharge

    Right but a 40W draw would continue to drain the battery. If it’s still a shallow discharge then that would save the battery. But the UPS still defeats the purpose if it’s not running fully down as the computer itself is still using power. So there would be no savings there.

    The only possible outcomes are 1) the UPS fully discharges or 2) the computer continues to receive power. One ruins the battery the other defeats the purpose. :)


    Ossian
    Moderator
    #191688

    Hi Jeremy,
    I agree with your last, except for the software element – I use APC PowerChute which detects when the UPS (connected via USB to the PC) has dropped onto battery power and then triggers the shutdown (either immediately or after a delay). Surely that changes the equation?
    (I have to say, I have never used a UPS as I suggested – for regular shut downs, but certainly have had them trigger clean shut downs in the event of power failure and have had charge remaining in the UPS battery after the shutdown.)


    JeremyW
    Moderator
    #271494

    Oh, maybe I’m misunderstanding Keke’s goal. I thought Keke wanted to disconnect the power after the computer shutdown.Keke was saying that after the computer shuts down it still has a 40W draw… but that seems extremely high for a shutdown computer…


    Ossian
    Moderator
    #191690

    I’m missed that bit – and am surprised at 40W even when shutdown – a couple of watts for WOL (but I’m sure with the right BIOS tweaking that could all be eliminated).

    If off, but powered really draws 40 W, the UPS solution as specified will not work


    Kyuuketsuki
    Participant
    #312519

    OK,

    Looks like some clarification is needed.

    I’ve just done some measurements and the following is my normal power usage:
    * Running (background apps, Firefox and word): 130W
    * Switched Off: 28W

    I originally said 40W but my PC has since had the PSU changed, maybe other components, so things have probably changed.

    Anyway, because it takes time to shut down my tower PC, unlike a laptop on batteries, I want to switch the power off AFTER the system has shutdown. Best guess, about 5 minutes after. I suppose I was thinking of those pneumatic push switches you sometimes get in buildings where the landlord is trying to save electricity … obviously I realise that’s an entirely inappropriate solution unless I want to press the switch in every minute or so to keep my PC running (on the plus side it would keep me fitter, LOL).

    By Jove I’ve got it. I’ll use a pneumatic switch but when the PC switches on I’ll have it power a powerful fan that keeps the switch pressed in then, once the PC is switched off the fan stops and the switch is released … that would work … er … well … I should be a crazy inventor ;)

    Doesn’t look like this idea’s a goer then …

    Keke


    Ossian
    Moderator
    #191692

    28W = something like 35 hours running per kW used, so compare the cost of your electricity vs the cost of implementing a solution (or the cost of your time to wait for shutdown and then switch off). IMHO uneconomic.

    I do like the fan idea – are you related to W Heath Robinson, by any chance?


    Kyuuketsuki
    Participant
    #312520
    Ossian;n511114 wrote:
    28W = something like 35 hours running per kW used, so compare the cost of your electricity vs the cost of implementing a solution (or the cost of your time to wait for shutdown and then switch off). IMHO uneconomic.

    Fair point. Interesting too because something in the house is using a fair whack of power, guess I have to look further … what do Sky boxes use?

    Ossian;n511114 wrote:
    I do like the fan idea – are you related to W Heath Robinson, by any chance?

    I wish … nah, just the usual geeky IT batsh** crazy at times :)

    Keke


    JeremyW
    Moderator
    #271497

    What about one of those outlet timers that automatically go off/on at certain times of the day? Something like this: https://www.1000bulbs.com/product/63151/ELEC-TN311.html


    Ossian
    Moderator

    Kyuuketsuki
    Participant
    #312521

    Apologies, I was busy …
    [SING] “Busy doing nothing, nothing the whole day through, trying to find lots of things not to do…” [/SING]
    … the problem with unemployed is, I think, motivation. It’s really hard to motivate yourself to do anything.

    So that switch is like remote, I could walk away from my PC and switch it off at my leisure 5 mins later. Intriguing.

    Apologies for the singing (especially to Bing C.)

    Keke

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