P4400 Kill A Watt

The "Operation Manual" (actually a single sheet, one side) for the Kill-A-Watt Power Meter reads as follows:

"The watt/VA key is a toggle function key...The LCD will display Watts as the active power, where VA is the apparent Power..."

When I try to measure the power consumption of my small freezer and I select, for example, "Watts", the P4400 reads "64". Now, if I select "VA" it reads "90". Which is the right reading? How many watts is the freezer really consuming.
Can anyone tell me the difference between "real watts" and "apparent Power"?



  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: P4400 Kill A Watt


    Your fridge is drawing 64 W of power, or “real watts”. The “apparent power” is the mathematical product of line voltage and current, and does not take into account “power factor”, or the time delay between the voltage and current cycles.

    You can read all about “power factor”, “real power” and “apparent power” in this Wikipedia article: http://en.wikipedia.org/wiki/Power_factor

    Jim / crewzer
  • System2
    System2 Posts: 6,290 admin
    Re: P4400 Kill A Watt


    Once again I am in debt.
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: P4400 Kill A Watt

    What's the story on the Kill-A-Watt's relating to mod-sine inverters - are they now usable with them, or still strictly "sine wave" only? Which does NAWS stock ?
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

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