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Strange? as voltage drops amps draw drops???

Discussion in 'Home Power and Microgeneration' started by John Smith, Apr 15, 2006.

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  1. John Smith

    John Smith Guest

    I Was doing some testing today in my camper trailer.
    I hooked up a CT 800 watt digital inverter and pluged in a trouble light
    with a 9 watt ultra mini CF rated at 9 watts. My 12 volt lead acid was
    at 12.5 volts. The draw was 1.2 amps on the DC the
    voltage dropped down to about 11.5 the DC amps draw went down to about
    0.8 amps. The reverse of what I expected??? The voltage on the AC side
    of the inverter stayed at a constant 117 volts. Any thoughts anyone?

    Does any one no how the circuit works inside the base of CF
    lighting...IE does it take the AC and rectifie it into DC?
  2. John Smith

    John Smith Guest

    Amp clamp

  3. John Smith

    John Smith Guest

    My conclusion is that the CF bulbs like the MSW. Has anyone looked inside
    the base of a CF to see if one could be hotwired for direct DC?
    Dont tell the world about these amazing spiral bulbs....if everybody
    switched the power companys will just have to raise the price of power to
    make up thier loss LOL.
    Where I live the bulbs just took another 1/3 price drop down to about 2 CDN
    bucks a piece. Judging by my power bills we are saving about 1000 kwh a
    month off the grid and maybe more since we swithced to whole house CF. Got
    four teens that don't know what off is on a switch.
    Another question is do those double fourty watt four foot flourecent tubes
    draw more than CF's for the same amount of light with the CF. I have one
    quad and 5 double fixtures to replace yet. My 12 volt mini Flourecnt draws
    2.2 amps compared to about .8 on the inverter with on CF.

    Why to you think that the inverter is working harder just because the fan
    is on?
    If its working harder it should be drawing more from the bank......maybe it
    is a cheap temp monitor inside....probably does not even monitor temp at
    all. It maybe only looking at the input dc and watts out to determine when
    the fan is on? Try freezing the inverter
  4. Jim Baber

    Jim Baber Guest

    Jim wrote:
    I've got a 33 year old who got mad at her landlord 3 months ago and
    moved back home until she could get a couple of thousand together (first
    and last you know) and find a house to share with a friend. This is not
    to mention my 31 year old son who brought his significant other with him
    when he moved back home last November. My wife and I had gotten used to
    our comfortable quiet coexistence with our 130 pound over aged puppy (a
    6 year old Akita) over the prior 5 years. Now we have a house full once
    again. And some of you may wonder why I worry about my power bill?

    I sympathize with the beemer, but 3 extra adults are worse than 4 teens,
    the teens at least sleep more the lights around here are still on at 2-3
    AM, and the washer and dryer seem to run continually. Not to mention
    there is frequently 3 or 4 separate meals prepared for each mealtime
    because of personal preferences.

    The amp drop with voltage drop question is interesting, I have noticed
    my own CFLs seem to take longer to come to their full lumen output the
    older they get, and I wonder, if this is a symptom of the same
    situation. I haven't tried to measure the drops on mine, I'm too busy
    turning off the lights.
    Jim Baber
    1350 W Mesa Ave.
    Fresno CA, 93711
    (559) 435-9068
    (559) 905-2204 (Verizon IN cellphone (to other Verizon IN accounts))
    See 10kW grid tied solar system at ""
    See solar system production data at ""
  5. Almost definately a heating problem causing high resistance somewhere.
    It could be in the Battery Bank itself or just a main connecting wire?
    More than likely before the inverter.
  6. Me

    Me Guest

    Your problem is that you were to nice to them as Teenagers, and they
    still think they are.....You just weren't Mean enough to them, so that
    at their 18th birthday, they took the presents and RAN, as fast and as
    far as possible....... Then after they turned 23 or so....and had LEARNED
    enough to actually live on their own, they could come back for
    Thanksgiving, Christmas, and Easter.......

    You guys got to LEARN, that once these kids move away, they only get to
    come back once, after that it is "Stop by for a visit but plan on
    leaving in a day or two", UNLESS you got Grandkids, and then it is out
    by midnight.....but feel free to let GrandMa babysit as long as you
    promise to come get them before MIDNIGHT....and we can SPOIL them Rotten,
    fill them up with Sugar, tell them all the things you did as a child,
    and still you MUST pick them up by MIDNIGHT....

    Me been there, done that, and GrandMa still sets
    the RULES... Midnight.... Right?
  7. Malc

    Malc Guest

    Not necessarily. It could have a Hall effect device in it.
  8. Malc

    Malc Guest

    I've told my kids that just as Homer Simpson says, "Once you're 18 you're
    out the door."
  9. John Smith

    John Smith Guest

    YA I guess they do???
    And mine reads DC as well...mind you you gotta rotate the switch to the
    DC- position and when reading Ac back to Amps~..........lo and behold
    thanks for the hot tip by jesus.
  10. John Smith

    John Smith Guest

    NO really! All along I thought it was the moons gravity and the neighbours
    dc viberator that I was compensating for.
  11. Yup.

    If output load on the inverter is constant (measure voltage and amps
    while powering a pure resistive load) then the input power would remain
    constant IFF the inverter efficiency remains constant.

    I suspect that when input power decreases, your inverters output power
    is also decreasing.

  12. Well, unless you want to start arguing that your inverter violates the
    laws of physics or is pulling zero point energy from the ether, you are
    missing something. If the input power decreases the output power must
    also decrease. Doesn't matter what you think your meter is telling you.

    It takes four good measures at near the the same moment in time to do
    this... input voltage, input current, output voltage, output current.
    And since the output is A.C., it has to be a nearly pure resistive load.

  13. You

    You Guest

    time for you'all to drag out the old Tek Dual Trace Scope and really
    "SEE" what is going on. Lock one Trace to the output waveform voltage
    probe, and lock the second to a current probe. Look at waveform, power
    factor, ect. and make some better judgements of the situation.......
  14. Yup. (Well, I've got an old HP 'scope, but yeah. ;)

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