1500 watt inverter questions

Discussion in 'General Electronics Chat' started by ShockBoy, Feb 2, 2011.

  1. ShockBoy

    Thread Starter Active Member

    Oct 27, 2009
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    I've recently purchased a 1500 watt inverter that seems to be having some issues that I can't explain. I don't want to send it back for an exchange if something else is the issue.
    First the model is Cobra CPI 1575.

    When I first turn it on, the two fans in the back whir up then it beeps flashing "OLP" (overload protection), then it does what it's supposed to do; flash the battery voltage then the watt output.

    Next I grab my volt meter and check the AC output voltage through the plugs in the front and it reads 98.0 Volts. It's not even close to 120 Volts.

    Could that be I need heavier gauge wire from the battery to the inverter?
    Could it be I'm only running one battery?

    One other thing is when I plug lower power items into it, the output shows zero watts, but plugging in an old fan, it shows the watt usage?

    I am quite confused at why it's doing what it's doing.. Any advice would be appreciated. (before I pay to ship it back for an exchange)
     
  2. Wendy

    Moderator

    Mar 24, 2008
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    What is the battery voltage it is showing?
     
  3. ShockBoy

    Thread Starter Active Member

    Oct 27, 2009
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    13.4 Volts. It's on float charge
     
  4. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
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    It's designed to be on a running car or truck battery while the engine is running, at 1500W that's about 120A from a 12V source your car battery will boil. You need very short and very heavy gauge wire to boot.
     
  5. ShockBoy

    Thread Starter Active Member

    Oct 27, 2009
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    4 gauge at about 2 foot long is what I was thinking.

    So I should check it on my truck before I send it back?
     
  6. Wendy

    Moderator

    Mar 24, 2008
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    Last edited: Feb 2, 2011
  7. ShockBoy

    Thread Starter Active Member

    Oct 27, 2009
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    13.4 is with no load. It leveled off at 12.1 Volts with load, but the low volt output of the inverter made the fan buzz a bit.
     
  8. marshallf3

    Well-Known Member

    Jul 26, 2010
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    What kind of load are you presenting it? If totally inductive that could be part of the problem.
     
  9. ShockBoy

    Thread Starter Active Member

    Oct 27, 2009
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    It's an old desktop fan from the 60's. Smaller loads such as charging a cell phone show no watt usage at all.
     
  10. marshallf3

    Well-Known Member

    Jul 26, 2010
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    Totally inductive and probably rather inefficient load.

    Have you tried putting a few light bulbs on it?
     
  11. ShockBoy

    Thread Starter Active Member

    Oct 27, 2009
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    no, but I will try that.
     
  12. marshallf3

    Well-Known Member

    Jul 26, 2010
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    Well, let's see what it does. If you've got good wiring and a good battery it should be able to run a couple of 250W heat lamps.
     
  13. ShockBoy

    Thread Starter Active Member

    Oct 27, 2009
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    I just tried a 75 watt black light bulb and got a current overload protection error and a low voltage protection error. Bulb was warm to the touch. The battery at 12.6 volts at the start of the experiment. During the experiment the voltage dropped down to 11 volts and the black light blinked every 5 seconds or so. Changed the bulb to a compact fluorescent bulb gave me no error, bulb lit up and inverter watt display read 000 watts...???
    It's got to be my battery/cable thickness...
     
  14. ShockBoy

    Thread Starter Active Member

    Oct 27, 2009
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  15. marshallf3

    Well-Known Member

    Jul 26, 2010
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    Yea, I think you got a bad one or it was poorly designed to begin with.

    Believe it or not Harbor Freight has some decent inverters as does NewEgg.
     
  16. ShockBoy

    Thread Starter Active Member

    Oct 27, 2009
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    Great.

    Thank you for the help.
     
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