Amp Usage? Chart Conversion Table??

Discussion in 'Talkback' started by mlind, Apr 29, 2003.

  1. mlind

    mlind New Member

    Hi All,

    I just purchased a 34' 1999 Thor fifth wheel, with 2 slide-outs and plan to live in it full time. Can anyone tell me where I can find a chart to figure out amp usage on my appliances? A/C, T/V's, overhead fan, lights, microwave, VCR, DVD Player, hair dryer, etc? How do I figure out amp usage/combinations to prevent blowing out a fuse?

    Also, most parks in Northern FL are 30 Amps. Is that enough to keep the A/C running while I'm at work during the day to keep my pets cool (yellow lab/retriever mix and a 200 year old cat), if everything else is unplugged? I'm already expecting to keep everything unplugged, unless I need to use it, as well as lights. Should I plan to invest in battery operated lights, to cut down on amp usage, and what to buy?

    Also, I purchased a 1 ton Dodge diesel dually; Cummings engine with 98,000 miles. Will this be able to pull the fifth wheel without problems? How easy is it to pull a fifth wheel, since I'm the only one to handle hook-up and parking? It already has a 5K gooseneck tow package installed in the bed of the truck, with a tow gate. Is this a good unit? It's huge. It takes up about 1/3 of the truckbed.

    This is a major lifestyle change for me, so I appreciate any advise you may provide.

    New to RVing, but looking forward to it!

  2. hertig

    hertig Senior Member

    Amp Usage? Chart Conversion Table??

    For a chart listing average consumption, you might check out a solar energy site. The only one I can remember is . For the real current usage, look at the information plate on each appliance or in their manuals. If the current is listed, there you are. If only the power (watts) is listed, divide power by volts to get current. For instance, if a microwave lists 1200 watts on its information plate, it would take about 10 amps (1200 watts/120 volts).

    In general, the trailer electrical center should be set up for safe usage. Just don't plug in a coffee pot, electric heater and hair drier into the same socket :)

    To avoid overloading a circuit breaker, sum up the current required by all the items powered from that breaker and ensure that total is less than the rating of the breaker. KEEP IN MIND THAT MOTORS HAVE A HIGH STARTUP CURRENT. This is usually quick enough that it won't blow the circuit breaker even if you do go over the breaker rating for that instant. You would not want to have 2 of them on the same circuit though, unless you could GUARANTEE they would never start at the same time (ie, not power a refridgerator and an A/C unit on the same circuit).

    If your trailer is 30 amps, you should have no problems running everything in it from a 30 amp service. If it is 50 amps, there is a good chance you have 2 A/C units. You can probably run 1 A/C unit from the 30 amp service but not both of them. Running 1 A/C, you probably won't need to get too crazy about unplugging other things too. Also, I think someone makes a gadget which allows you to phase the 2 A/Cs, so a 50 amp/2 AC trailer can get by using 30 amp service.

    Another option, some parks have 30 amp service and 20 amp/15 amp service. Camping World has an adapter which allows you to run a 50 amp trailer off a combination of 30 amps and 20 amps services. Might want to check out the parks in your area to see if this is a possibility.

    Most of the lights mounted in the trailer are probably 12 volts. They run off the batteries in the trailer, which are charged by the converter in the trailer. Thus buying 'battery powered' lights probably won't get you much. Replacing the incandescent light fixtures with low power flourescent or LED fixtures may allow you to use the lights longer from battery power, but if you are mostly plugged in to a park's service, this likely won't make a significant difference.

    A 1 ton diesel dually should be a towing monster. Without knowing the ratings of truck and the weight of the trailer, I can't say for sure whether it can safely and effectively do the job, but I wouldn't be surprised if it did. One problem might be if it is a shortbed, but this can be overcome with the right hitch.

    Hooking up a 5th wheel trailer is simplicity itself, as long as you can see both the hitch and the pin. Detaching is even simpler and you don't even need to be able to see the hitch. Pulling the trailer, if the truck is right for it, is no problem either. Just be aware of your extra length when changeing lanes and pulling through intersections, height when going through tunnels and under trees, etc, and weight when stopping. With height and turning radius concerns, gas stations can be a scary place for 5th wheels... If you only go where the 18 wheelers go, you should be fine.

    Backing up is another story; find yourself a huge, empty parking lot, and practice lots. Even then, you will probably need someone to guide you or at the minimum watch out that you don't back into or over something. Or just decide that you will never, ever back up :). The keywords for this lifestyle are 'pullthrough' and 'foresight'...

    A gooseneck hitch is not a good choice for a 5th wheel. Sure, they make an adapter, but I don't know that I would trust it as far as I could throw a buffalo. And 5K is way, way, way too flimsy for your trailer. Without knowing its actual weight I couldn't say, but I'm thinking you'll need at LEAST a 15K hitch. I'd look into the PullRite 5th wheel hitch if I was on the market for one today, but any good brand (like Reese, etc) should suffice.

    If it doesn't already have it, outfit your truck with extendable or 'towing' mirrors. This allows you to see around the trailer which is wider than your truck and is important for safety. If you don't have them, there are nice ones available with lots of options, like dual mirror (flat and convex), heated, electrically adjustable and even with built in turn signals.
  3. BarneyS

    BarneyS Senior Member

    Amp Usage? Chart Conversion Table??

    I'm not sure you have a "gooseneck" tow package. You say it is huge and takes up 1/3 of the bed of the truck.
    That sounds more like a regular 5th wheel hitch to me. A gooseneck hitch is just a little ball located in the middle of the bed and not very high,sometime mounted on a small pedestal- unless you have some kind of gooseneck hitch I have not seen. Also, most 5th wheel hitches are rated for a lot more than 5K lbs. You might check with a hitch or RV dealer to see what you really have there.

    As far as the abilities of your truck, you may be at or over the limits of your truck. The Dodge 1ton dually is a "towing monster" but it does have its' limits and a 34ft Thor 5th wheel is a heavy trailer. I would advise you to go to a public scale and get both the trailer and truck weighed and see how the weights compare with the ratings for your truck. You might be surprised with how much they both weigh. The GVWR, Axle ratings, and GCWR should all be listed in your owners manual.
    Here is a link to the CAT scale website where you can locate a public scale.
    Good luck.

    Good luck.
  4. hertig

    hertig Senior Member

    Amp Usage? Chart Conversion Table??

    Right, the only way to know for sure that your truck will handle the trailer is to do the math:

    The Gross (maximum)Trailer Weight should be listed on the trailer. Often this is inside the door of a kitchen cabinet. This is the maximum weight of the trailer and all of its contents, including water, sewage and LP gas. The 'dry weight' of the trailer is the weight of the trailer without anything in it; it is estimated on the trailer weight sticker, but can only be known for sure by weighing on a scale as mentioned above. Often it will be significantly low due to options added to the trailer. The difference between GTW and actual dry weight is the weight of 'stuff' you can carry in the trailer without overloading it, which introduces safety and longevity concerns.

    If practical, it is best to weight the trailer actually loaded and insure this value does not exceed the trailer's GVW. If not practical, you can weigh the empty trailer and estimate the weight of your stuff. Using the specified dry weight of the trailer can provide an initial 'ballpark' feel, but get the real weight before hitting the highway.

    The truck has several ratings you need to be familiar with. It will have a Gross Combined Weight Rating, which is the maximum weight of the truck plus contents plus trailer plus contents. It will also have a Gross Vehicle Weight Rating, which is the maximum weight of the truck and contents, and a Rear Axle Weight Rating, which is the maximum weight on the rear axle. These should be on the plaque riveted to the driver's door.

    You may also be provided a 'towing capacity' or a 'cargo capacity'; be aware that these ratings are based on an empty truck, with no options, no hitch, little gas and only a 150 lb driver. This condition is known as 'curb weight', and like the trailer dry weight, does not always include some options added to the truck, or the realities of the world.

    You also need to know the trucks 'loaded' weight. Best is to load up the truck with a full tank, and all stuff/people/animals who would normally be in it, and get it weighed. Or you could get the 'curb weight' by specification or by weighing the truck empty, and then estimating the load.

    Ok, the first check is to ensure that the GTW + the GVWR do not exceed the truck's GCWR. If it IS over, you can get around it by not loading the trailer and/or the truck up to their maximum weights, but this generally is not a good sign... For sure, the actual loaded trailer weight plus the actual loaded truck weight should be less than the GCWR.

    Unfortunately, the trailer exerts weight on the truck, over the rear axle, in an amount known as 'pin weight'. This value, typically 10% to 20% of the trailer weight, should not cause you to exceed either the GVWR or the RAWR. Again, weighing the rig is your best bet.

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