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Cerevisaphile's avatar
Jan 12, 2014

That darn 12v cable...

I am not sure what i am doing wrong here.... I have a class c thor motorhome... I thought it would be nice to be able to watch TV when we are dry camping and since the RV doesnt come with an inverter and i dont want to make too many modification i thought the easiest solution was this.

Connect a 12 volt outlet to the 12 volt cable in the entertainment cabinett which is hooked up to the house battery.
Connect one of those cupholder inverters and run the tv and roku or media player to it.

Inverter is 200 watts 400 peak...not a pure sine

Tv draws 48 watts and roku/media player 5 watts

This is what happens...

Plug inverter in ..it shows green light..
Plug tv into inverter light flashes green/red...but tv works no issues
Plug roku in inverter flashes red/green and tv goes on and off
Plug in roku only light on inverter stays green

So for me that means the inverter can not handle the load..yet its just 25 % of the listed load.

Any suggestions ? I think i might get another inverter (pure sine)with a higher load that i can connect directly to the house battery and see if that fixes the problem

15 Replies

  • RoyB's avatar
    RoyB
    Explorer II
    It is easy to connect the Inverter with the proper sized 12VDC cable to the batteries. Then you can run as much as probably 100 feet of 120VAC Extension cord to where your home entertainment items are located without issues... I am not much of fan of the wall mounted 12VDC Power receptacles. They always got hot on me with the poor connections they offer when drawing over 5 AMPS or so....

    I used WIREMODE wire maintenance kits from LOWES to hide my extension cords and only the multiport receptacle is visibly on the back of the tabletop around the home entertainment units.

    I also would use a PURE SINE WAVE Inverter for any electronic units... It only takes one that doesn't like MSW TYPE inverter sine wave to ruin your day when it goes up in blue smoke.. Use to be the PSW Inverters were really expensive but not so these days. My 600WATT PSW AIMS Inverter only cost $149 and I never have to worry about anything going up in blue smoke.

    I started out with a 150WATT unit and liked it so well went to a 300WATT unit to run more items - I finally ended up with the 600WATT PSW unit and have two locations in my setup that has emergency power being the Home Entertainment Area and the Bedroom night table area. I leave my items plugged into the 600WATT Inverter unit all the time even when I am connected to shore power at the camp ground. Always ON... My normal capacity used from the 600WATT PSW Inverter is around 300WATTS... Having some reserve power is important to us as we camp alot off the power grid and usually re-charge our 255AH battery bank everyday at 8AM each morning so using more power is not much of an issue with us.

    Works good for us...

    Roy Ken
  • JaxDad's avatar
    JaxDad
    Explorer III
    donn0128 wrote:
    Even though the inverter may be rated for 200 watts, or about 18 amps, the cable is probably not large enough to support the load. In simple terms you are probably strangling the inverter.


    X 2, especially if the existing wire is already powering other items like the sound system.

    A 60 watt draw (5 amps) would max out a piece of 14 gauge wire after about 15 feet if my math is correct.

    If this is more than an experiment, run a new wire from the source to the outlet (fused at source) and run larger gauge wire. There's charts readily available on the 'net that will tell you what gauge wire you need for a given load at a certain length.
  • Hi,

    Hard wire the inverter to the battery bank. Keep it within 3 feet if you can. Use #10 wire.
  • Either
    the 12v supply has to be a heavy enough gauge to handle the load. I'm surprised it hasn't popped a fuse.
    or
    if the wire feeding the outlet is long you may be getting a voltage drop.
    The inverter is very touchy about the input voltage to make 110volts output. you may have too much voltage drop. Many Cig. lighter sockets are not wired to plug in anything much more than a cell phone.
  • Even though the inverter may be rated for 200 watts, or about 18 amps, the cable is probably not large enough to support the load. In simple terms you are probably strangling the inverter.

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