Calculating Inverter DC Power Consumption

Discussion in 'Power Electronics' started by vonsworld, Jun 28, 2016.

  1. vonsworld

    Thread Starter Member

    Apr 27, 2011

    I have a Samsung Monitor that I would like to run off an inverter attached to a 12v leisure battery.

    The monitor on the rear plate says that it will accept 100-240v and consumes 1 amp.

    My question is does this mean the monitor will consume 1amp at any of those voltages?

    According to an online calculator a 240v inverter attached to this monitor would use 240 watts and suck 22.08 amps from my 12v battery.

    However if I attach a 120v inverter that would only use 120 watts and use 11.04 amps from the battery. That is assuming the monitor requires 1 amp at either 120 or 240v.

    Please could you let me know if this is correct, Thanks Robin
  2. crutschow


    Mar 14, 2008
    1A is probably the maximum it will draw at 100V, since a switching power supply, which many electronic devices now use, tend to draw a near constant power from the mains. That would give a nominal power of 100W. If you look at the spec for the monitor it may state the power used.

    If you want better accuracy, you can measure the current or power (a Kill A Watt meter for $20-$30 can measure both).

    Note that you also need to include the efficiency of the inverter (perhaps 80%-90%) in your calculations for battery current.
    Last edited: Jun 29, 2016