count down timer to switch off loads?

notsobright
notsobright Solar Expert Posts: 247 ✭✭
in Off Grid Solar & Battery Systems #1
anyone know of a count down timer that I can use to set/program as a switch to turn off a 12 volt load after 1-20 minutes?


preferably something simple/cheap

I keep forgeting to turn off my 12v tea pot so I just need something I can set to turn off the load after so many minutes.

thanks
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Re: count down timer to switch off loads?

    On the high end of the solution, from our host:

    Flexcharge DC Timer Controller $71.50
    wind-sun_2149_61034474 This controller will directly control both AC and DC loads up to 16 amps non-inductive (lights, heaters etc.) or 8 amp ... loads (motors, pumps, fans, etc.). Will control up to 240 volt AC or DC (but not recommended for over 48 volts DC). This requires a 12 volt battery to operate the timer and internal relay. The timer draws only a few milliamps, so can operate from one side of a 24 ...

    You can also use a simple mechanical twist timers used with AC lighting--Perhaps using a 12 volt relay if the current is too much for the mechanical timer.

    Other ways could involve a limit switch and temperature sensor (water approach boiling, turns off relay), etc..

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • SCharles
    SCharles Solar Expert Posts: 123 ✭✭
    #3
    Re: count down timer to switch off loads?
    BB. wrote: »
    On the high end of the solution, from our host:

    Flexcharge DC Timer Controller $71.50
    wind-sun_2149_61034474 This controller will directly control both AC and DC loads up to 16 amps non-inductive (lights, heaters etc.) or 8 amp ... loads (motors, pumps, fans, etc.).

    -Bill


    I use one of these for a 12 v. fan for some electronics and it's been working for 15 years or more. Easy to set the timer, and you can run several devices with different times, if you want. Well worth the money.
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #4
    Re: count down timer to switch off loads?

    A simple clock wind 120 vac switch will work fine for such a load.

    I have a simple Intermatic (available nearly anywhere ~ $10) wire to the radio/stereo system. It winds down from ~ 5 minutes to 1 hour, and has a hold on position. I dial it up when we go to bed with music on, and it switches every thing off.

    Even though it is rated for AC your tea pot probably doesn't draw enough amperage to worry about on DC. By turning it on before you put the load on will reduce any arc from the contacts an lengthen service life.

    Tony
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  • notsobright
    notsobright Solar Expert Posts: 247 ✭✭
    #5
    Re: count down timer to switch off loads?
    BB. wrote: »

    You can also use a simple mechanical twist timers used with AC lighting--Perhaps using a 12 volt relay if the current is too much for the mechanical timer.
    l

    I have a mental block when it comes to using 120v components in 12v aplications. as a result I completely overlooked this solution and I allready have this component on a shelf somewhere!


    thanks!
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