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Power inverter stuck on 12.5v help

Discussion in 'General Hardware' started by mtjsr, Mar 5, 2013.

  1. mtjsr New Member

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    Hi all, new member with a tough inverter issue. But first I have to tell you this stuff cause It might matter. I have a logan coach enclosed motorcycle trailer, all the lighting fixtures inside/out are DC, the fixtures white wires are hooked to a white wire that is running thru the trailer, the black fixture wires are just cut off and the fixtures metal frames and screwed into the metal trailer walls. So it appears the body of the trailer is the ground or negative?

    I hooked a 1000w inverter to the positive and negative of a deep cycle marine battery on the trailer as required, but the ground wire coming from the inverter was hooked up to the white trailer ground wire by the tongue. When I turned on the inverter it read 12.5v and the ON light was on, the fan was off. I plugged in a small vacuum into the inverter and the vacuum came on for just a second and then shut off and the inverter immediately beeped for a few secs. Thinking my ground was bad on the trailer, I hooked up a temporary long ground wire that went from the inverter to my trucks body as a bypass thinking the body of the trailer might be the problem. The digital readout still shows 12.5v on the inverter.

    Any ideas why I am not getting ac or a volt ac output reading on the digital readout?

    All ideas welcome, thanks everyone. Mark
    Last edited: Mar 5, 2013
  2. 1freedude

    1freedude

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    I'm sure you are overpowering the inverter with the vacuum. Try something with lower watts, Ike a desk lamp or the such. Inverters don't like inductive loads.

    Also, put a multimeter on the battery to check volts. Check with trailer power connected and disconnected.
  3. Aquinus

    Aquinus Resident Wat-man

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    It wasn't a full sized vacuum was it? As free dude said modified sine wave inverts don't tend to like inductive loads, they're also less effective as well and you could damage the device. Vacuums also tend to draw a ton of power so you could have over loaded the inverter or your input voltage into the inverter could have dipped. You could attempt to smooth the output by putting a high load capacitor on the +12v before the inverter. Also keep in mind that deep cycle batteries only provide so much current, this isn't a car battery with several hundred cold cranking amps.

    Could you tell us what kind of battery that you're running the inverter off of?
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  4. jaggerwild

    jaggerwild

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    Your on a GM car with the white wire? If so that is a parking light wire, as asked put a low draw on the inverter.
    The inverter will show high voltage till its under a load......
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  5. mtjsr New Member

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    Thanks all, the vacuum was a small dirt devil canister type, the inverter never worked from the start. When I turned it on, the readout read 12.5v It was when I turned on the vac that the inverter beeped and shut off.

    The white wire is not on my truck but on my trailer and the trailer spec says it is the ground wire.

    The battery is a Kirkland Costco heavy duty deep cell marine battery, model number or size not sure here at work. Which battery is better for an inverter, deep cell or regular truck battery?

    Is it possible a trailer is a poor ground in a dc system?
  6. 1freedude

    1freedude

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    12.5v is within spec of most inverters.

    This number also indicates the SoC (state of charge) of the battery.

    Charge the battery, and it will go up. Use the inverter, and it will go down.
    Last edited: Mar 5, 2013
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  7. Sasqui

    Sasqui

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    Try plugging in a incandecent light into the inverter for a test.

    Inverters typically produce a square wave, which works fine for many things, not so much for others.

    Oh and welcome to TPU :toast:
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  8. newtekie1

    newtekie1 Semi-Retired Folder

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    Even that type of vacuum can overload a 1000w inverter, even a basic vacuum motor can easily pull 10amps which is 1200w.

    The readout on the inverter is the input voltage, it is there to tell you the charge in your battery.
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    Crunching for Team TPU More than 25k PPD
  9. mtjsr New Member

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    It works!!!!!!!!!

    A huge thank you to everyone for helping solve my inverter issue. In the end, a hard reset solved my issue. I left it exactly how I hooked it up, but disconnected the positive lead and then re-hooked it up. I guess the inverter is suppose to read the input volts after all. It had me fooled as the readout is on the output side of the inverter. I stuck the probes of my flukemeter into the plug openings on the inverter and it read 115 volts AC. I then plugged a small desk lamp and all is good.

    Since this is a new toy hauler trailer that I just installed an LED tv, dvd player and car stereo I then hooked the entire entertainment center up and proceeded to watch a movie and listen to an entire cd of music. After all that draw, and 2 hours later, the input readout meter read 12.30 vdc.

    Life is good!

    Thanks again, Mark

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