Inverter sizing

Discussion in 'Solar Power' started by manda3000gt, Mar 28, 2015.

  1. manda3000gt

    manda3000gt Funster

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    According to my NASA BM1 when I turn on my 1500w pure sine inverter switch on the Sky receiver, 32" tv & soundbar the amphr usage goes up by around 14amps, With the inverter on and only the Sky receiver on standby the usage goes up around 4amps (a good half output of one solar panel)
    The 1500w inverter came fitted when I bought the motorhome and supplies only the sockets that run the TV, Sky box etc which seems like overkill so thinking of swopping it out for a Victron 350w to save the amps.
    Will 350w be man enough for 14amps ?? Been on a watt to amp convertor and 350w constant (700w peak) should be good for around 27amps, thought I would ask the question on here as the regular posters seem genned up on power usages etc (y)
     
  2. jonandshell

    jonandshell Funster

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    Isn't it cheaper to simply switch off the sky box?
    It'll be that using most of that current, not the idle inverter.
    Our 2100w inverter is left on all holiday with negligible current draw when idle.
    I would try that first before throwing money at it!
     
  3. manda3000gt

    manda3000gt Funster

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    Sky box left on as recording different programmes day and night
     
  4. Wildman

    Wildman Read Only Funster

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    then you will end up with flat batteries.
     
  5. manda3000gt

    manda3000gt Funster

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    580w of solar into 4 Trojan T145 think it will be ok,
    I've got 2500w inverter that runs ring main sockets microwave etc just thinking the 1500w to power Tv etc seems over large and I do like to tinker , 350w Victron approx £120 (less what I move the 1500w on for)
     
  6. Reallyretired

    Reallyretired Funster

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    The inverter is a bit of overkill for the use you have, however a smaller inverter will not draw significantly less current if the output load remains the same. It would appear your sky box is about 40watts, which seems high but may be correct as its not really on standby, if its recording all that stuff as well. Have a look at the rating plate on the back, it will tell you the wattage and if its around 30-40w then using a smaller inverter will make no difference.
     
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