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Power Inverter problems

Discussion in 'General Hardware' started by donnygs, Nov 15, 2011.

  1. donnygs New Member

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    Hi all,

    I am having a problem getting my laptop to charge in my work truck.

    I am using:
    -2011 Dodge Ram 3500 with a diesel engine. (Had the exact same problem with a 2010 Ford F-350 gas engine)

    -Wagan Smart AC 120W USB Inverter (has a 3 prong outlet for my laptop cord to plug into)

    -Samsung RV515 laptop

    The problem I am having is the laptop wont charge (doesn't matter if the laptop is on of off) while the truck is running. But if I turn the truck off and rotate the key to the "Accessory" position it works.

    My truck is equipped with a MTC (Medical Treatment Centre) which is basically a cap mounted in the bed that is used to transport and treat patients. I don't have any of the lights or heaters turned on in the MTC when I experience this problem.

    So why does my laptop only charge when my truck is off?

    Thanks all!!
     
  2. Mussels

    Mussels Moderprator Staff Member

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    the voltage from the socket must be too low or too high, for the laptop charger to use.
     
  3. Sinzia

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    That sounds more like an alternator issue... when its in the accessory position its running off the 12 volt battery, but when the truck's running its getting the power from the alternator.
     
  4. white phantom

    white phantom New Member

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    yeah defo far from a mechanic but i agree with what mussels n sinzia are both saying it sounds like a problem with the voltage getting to the socket when the trucks running since it works when the engines off rules out a dodgey socket
     
  5. donnygs New Member

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    hmmm... I like the idea of power coming from the alternator vs. coming from the battery. That must be it. It can't be the socket because I have 4 sockets to choose from in this truck, 3 sockets in the Ford and they all have the same result. The battery power must be different than the alternator power. I wonder how I can fix this problem...
     
  6. Mussels

    Mussels Moderprator Staff Member

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    better altenator, or better inverter.
     
  7. Sinzia

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    Alternators run around 14 volts, the battery's at 12 volts... that's why all car electronics have a power supply built in somewhere that will run from 11-14 volts.

    Does something like a radar detector or some other piece of electronics work? nothing like a light, but something that's more complicated work? If not, then I'd have your alternator looked at.
     
  8. Mussels

    Mussels Moderprator Staff Member

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    a better inverter might be the best solution, one that can handle the higher voltage while the alternator is providing power, smoothing it down for the laptops charger to handle it.


    cheaper and easier than testing/replacing the alternator in multiple vehicles.
     
  9. Jstn7477

    Jstn7477

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    Since it happens in 2 different vehicles, your power inverter's overvoltage protection circuit may be broken or out of calibration, causing the power inverter to shut down thinking the line voltage is too high. A fully charged (and unloaded) car battery usually has a voltage of about 12.8V, and the alternator outputs roughly 14V, depending on engine RPM and the amount of accessories or lights engaged. The power inverter should accept an input voltage of about 10-16V DC.

    Are there any status lights on the inverter. For instance, when it works, is there a green light, and if there is a low battery/fault light, does that turn on when the power inverter fails to operate?
     
    Crunching for Team TPU More than 25k PPD
  10. donnygs New Member

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    I can charge my android cell phone multiple ways. I can charge my cell phone using a car charger and using the same inverter with the wall outlet charger that came with the phone. There is also a 2 prong outlet in the dash of this truck that will charge my cell phone no problem.

    My buddy also charge its tablet PC directly from the 2 prong outlet in the dash.

    I don't think there is a problem with my alternator since this happens in two completely different trucks.

    Thanks everybody for the ideas
     
  11. donnygs New Member

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    sorry I didn't see the two last comments there. There is a blue light on my inverter. its blue when the truck is off and supplying power to the laptop and its blue when the truck is on and not supplying power.

    I checked the fuse and its fine.

    here are some stats on my inverter.

    True-rated™ Power: 120W Continuous
    Peak Surge Power: 300W
    AC Voltage Output: 110V ± 5V AC RMS
    USB Output: 0.5A
    Optimum Efficiency: 90%
    Input Voltage Range: 10V to 15V DC
    No Load Current Draw: 0.15A
    Low Battery Alarm: 10.5V ± 0.5V DC
    Low Battery Auto Shutdown: 9.5V ± 0.5V DC
    Cooling Fan: Yes
    AC Outlet: Single
    USB Power Port: Single
    Net Weight: 3.4 oz (97 g)
    Gross Weight (with adapters): 5.5 oz (156 g)
    Dimensions: 2.8 in. x 3.7 in. x 0.8 in.
    (7.0 cm x 9.4 cm x 2.1 cm)
    UPC: 084367-02382-7

    I think I agree with the census saying that I need a better inverter
     
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  12. donnygs New Member

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    in my manual it says if the light is solid blue I have 120 watt of power source. If it is blue and blinking the power source is getting deprived. It's always been solid blue
     
  13. Mussels

    Mussels Moderprator Staff Member

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    doesnt mean it cant be outputting too high a voltage for the laptop brick to handle.
     
  14. donnygs New Member

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    ok I turned on all lights in the truck and in the mtc, have heat in the truck and in the mtc on. Radio is on. There is also a Motorola car phone and a Kenwood land mobile radio hardwired into the trucks power source. everything is on, Wouldn't that draw down my voltage A LOT?
     

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