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kmb1966's avatar
kmb1966
Explorer
Oct 22, 2018

Inverter install idea. We have no inverter

We are the new to us owners of a 2003 Newmar Dutchstar. This unit did not come with an inverter. I have an idea on how to possibly install an inverter in this unit, but would like some feedback on this install idea:
The battery system is in the bin next to where the inverter system is usually installed by Newmar. My idea is to install a 2000 or 3000 watt inverter in that bin, since it will be a short run to the battery system and the inverter remote can be easily ran inside a cabinet at that point so that the inverter can be turned on/off from inside the unit (close to the breaker box). Then using some #10/2/G wire (was considering the metallic shielded type) running the #10 wire to the other side of the motorhome where the 50 amp power shore cord area is located. I can see a direct shot from the inverter bin to the power shore cord area.
In the shore cord power bin area, install a 30 amp receptacle.
The procedure would be to plug the 50 amp shore cord into the 30 amp receptacle using the dogbone(50/30 adapter). When traveling leave the connection plugged in, and turn OFF the charger on the breaker box, turn ON the inverter. (Obviously do not turn on the air conditioners). By this method, all plugs should be 110v running on the inverter. If desiring the run the generator and air conditioner, we would turn OFF the inverter, start the generator, turn back on the charger.
Does this make sense? does anyone else hook up their inverter this way? Is there a better more reasonable method?

18 Replies

  • My Microwave is a hog. It draws 207 amps which my alternator could certainly not sustain for any long period of time--unless I wish to replace the alternator.

    I do have manual control over the dual charging circuits and they are protected by twin 50 amp automatic circuit breakers. It is interesting to watch the ammeter as they "wink" on and off.
  • theoldwizard1,

    Please resize the width of the photo. It makes it hard to read when one has to scroll from side to side on nearly every line in the thread.

    You must have one heck of an alternator if you are able to sustain running a roof air conditioner. I could do about 20 minutes @ 1200 watts before the starter battery dropped to 12.7 volts. That was with 256 watts of solar "helping" out.

    I'll go back to doing the 1200 watts now that I'm no longer full time. My duty cycle is 20 minutes "on" and 30 minutes "off".
  • MrWizard wrote:

    battery bank size is NOT primary importance if this is intended for drive time medium loads with engine running

    battery bank becomes important for overnight use and large loads like Coffee maker or MW

    With properly sized wiring, even a "smart charging system" will MAINTAIN a well charged battery bank while driving and running house A/C or other heavy loads.
  • msturtz wrote:
    I would recommend that you install an inverter with an internal automatic transfer switch. Magnum Energy and Xantrex have inverters like this. If you want to simplify this even further you can get an inverter that has an internal ... charger which would eliminate the stand alone converter.


    That is the way to go ! Disconnect the existing converter and wire the DC distribution (fuse) panel directly to the battery bank.

    Samlex makes several model like this that are very easy to install because all connections are made at the inverter/charge/transfer switch.

    House batteries connect to #1 and #2. Output from solar charge controller (if you have one) connect to #3 and #4.



    The rest of the connection go here.



    The installation manual has instruction for how to wire this to automatically start the generator.
  • he said while driving.
    that means alternator power is availble for battery charging

    he has an onboard generator and converter to recharge if needed

    why ?? IDK

    battery bank size is NOT primary importance if this is intended for drive time
    medium loads with engine running

    battery bank becomes important for overnight use and large loads like Coffee maker or MW

    my PSW inverter uses 88 amps to power my 750 cooking watts MW, my alternator can handle that IF it has too, it has not been necessary
  • First question, why?
    Second question, what do you want to power?
    Third question, how big is your battery bank?
    Last question, how do you plan to recharge the batteries?
  • How many batteries do you have? Need 4 to 6+
    You need 2/0 wire from inverter to battery not #2.
    Whole house is fine.... also need to set fridge to propane (unless it is a residential style with compressor) and the water heater on propane etc.

    If you are just running a tv or charge small items you may only need 350 watts or less. Anything big gets the generator right? Simplifies install. OK to use a small transfer switch on just the branch circuit you need would eliminate the heavy draw items and keep inverter safe from other power sources.
  • I would recommend that you install an inverter with an internal automatic transfer switch. Magnum Energy and Xantrex have inverters like this. If you want to simplify this even further you can get an inverter that has an internal converter/ charger which would eliminate the stand alone converter. The way the inverters with internal transfer switches are wired is a 30 amp split phase or single line and the circuits you want powered by the inverter would be wired downstream from the inverter. The inverter would be connected to the battery using two 2 ought power cables depending on the size of the inverter 2Kw vs 3Kw. I would use Blue Sea Systems fuses to protect the circuit. The inverter will automatically sense shore power and use that.