Forum Discussion

ahamade's avatar
ahamade
Explorer
Mar 11, 2014

Magnum MSH3012M Inverter Install

Hi guys, I am working on installing an inverter into my RV and was wondering what the proper way to hook up the AC power.

My RV has 30 Amp service. It currently has a WFCO WF-8955PEC Power Center. This contains both my AC & DC circuits. My new inverter supports up to 3000 Watts & can draw from shore power & my batteries at the same time.

I have the DC side figured out as thats pretty simple. The AC side has me totally stumped. The documentation states I should install a 60 Amp single pole breaker for the AC Input to the inverter & a 60 Amp breaker for the AC Output from the inverter. My WFCO Power center can not support a breaker that large so I can't use that as the input breaker panel.

Does anyone know of a solution for my AC input to the inverter? I want my converter to work when plugged into shore power or when on generator, so should I split the input power cables that are going to my WFCO Power center to also go to the input of my inverter? This way when I am on shore/gen power both the converter and the inverter get power? This would allow me to keep my AC, Water Heater, & Fridge on the AC switch panel built into the WFCO Power center.

As for AC Output from the inverter, I would install a sub panel that has a 60 Amp Breaker for the inverter then 3 20amp breakers for Microwave, GFCI, & Receptacles. Does anyone know of a sub panel that is made for RV's that would support what I am trying to do?

Any help on this would be appreciated as the entire design is a work in progress.
  • pianotuna's avatar
    pianotuna
    Nomad III
    Mar 11, 2014
    Hi,

    There is no need to plug the 120 volt input for the Magnum into the 120 volt panel in the RV.

    I just purchased the same inverter.

    Here is a flow chart of what I plan:

    New Shore Power to Magnum input; Magnum output to OEM RV Shore Power.

    I do have the remote that will allow me to limit shore power to various levels. I am hoping for help on how to adjust that.

    When running from the generator, I will plug the input of the Magnum into the output of the generator.

    I will be leaving my OEM converter in place but the 120 volt input to it will be a default of disconnected.
  • ahamade's avatar
    ahamade
    Explorer
    Mar 11, 2014
    Hi, thanks for replying so quickly!

    My RV came with an automatic transfer switch for my gen/shore power. I could have the output power from my transfer switch to go to just my inverter but then my converter is no longer usable because I do not want the 120V output from my inverter to go to my WFCO Power Center (converter).

    Basically I would like to have my inverter connected in a way that I can still use my RV as I do today but with the ability to have 120V power when dry camping.

    One thing also, since the inverter has a charger I no longer want to use the charger from my converter. I would much rather the battery charging to come from the inverter. I am not sure if its possible to disable the battery charger feature on the converter but it still work as it normally should.

    BTW I don't see the flow chart.
  • 2oldman's avatar
    2oldman
    Explorer II
    Mar 11, 2014
    I'll keep this as simple as possible and tell you what *I* would do ( and did) with a Prosine 2.0 IC. It's called a whole-house setup, which means it's simply another AC source for your entire coach.

    First, your WFCO should be disabled, as should your transfer switch (maybe..see below). The Magnum can take care of everything, including being a surge supressor/power police unit. My Pro had all that functionality too, so I assume yours does. (No, I haven't read the owner's manual) If that's a fact, you want the M to police all your incoming shore power. With a subpanel you won't get that, plus it's a lot of work. I don't see what kind of generator you have in your profile, so I'll assume it's outboard (portable). The wording you used leads me to think it may be built-in, so perhaps you'll correct me. If so, then the xfer switch comes before the M AC input.

    Put the incoming AC from shore to the M, and the outgoing to your AC panel. That's it, you're done.

    This way, you get protection from bad shore, you get hybrid support if your generator can't handle it, and, your whole coach runs on it.
  • pianotuna's avatar
    pianotuna
    Nomad III
    Mar 11, 2014
    In your case

    SP(or Gen)--> Transfer switch--> Input to Magnum (cut the cable)--> Output of Magnum to Power distribution center.

    Turn off the breaker for the OEM converter, or put a switch in the line (or unplug, if it is like mine).

    Set Fridge to gas only.

    ahamade wrote:
    Hi, thanks for replying so quickly!

    My RV came with an automatic transfer switch for my gen/shore power. I could have the output power from my transfer switch to go to just my inverter but then my converter is no longer usable because I do not want the 120V output from my inverter to go to my WFCO Power Center (converter).

    Basically I would like to have my inverter connected in a way that I can still use my RV as I do today but with the ability to have 120V power when dry camping.

    One thing also, since the inverter has a charger I no longer want to use the charger from my converter. I would much rather the battery charging to come from the inverter. I am not sure if its possible to disable the battery charger feature on the converter but it still work as it normally should.

    BTW I don't see the flow chart.
  • ahamade's avatar
    ahamade
    Explorer
    Mar 12, 2014
    Hi guys, thanks for the replys! My generator is a 4000K Onan built in generator. If I take the converter out of the equation by cutting its power then when I am plugged into shore power I do not get the benefit of running my 12 volt appliances off of shore power as they will always be running off of the battery. Is that not correct?
  • 2oldman's avatar
    2oldman
    Explorer II
    Mar 12, 2014
    ahamade wrote:
    If I take the converter out of the equation by cutting its power then when I am plugged into shore power I do not get the benefit of running my 12 volt appliances off of shore power as they will always be running off of the battery.
    That is correct, but your nice new IC will be charging the batteries at the same time. I'm pretty sure it can handle your 12v needs, which is identical to running off a converter.
  • pianotuna's avatar
    pianotuna
    Nomad III
    Mar 12, 2014
    Hi ahamade,

    No, that is not correct because the Magnum will be providing for the 12 volt needs when you are on shore power, up to 125 amps @ 12 volts (nominal).

    The converter can be used as a back up, or even at the same time as the Magnum. But the Magnum blows a wfco converter pretty much right out of the water as far as speed of recharging, and as an added benefit has temperature compensation.

    ahamade wrote:
    If I take the converter out of the equation by cutting its power then when I am plugged into shore power I do not get the benefit of running my 12 volt appliances off of shore power as they will always be running off of the battery. Is that not correct?
  • GordonThree's avatar
    GordonThree
    Explorer
    Mar 12, 2014
    another benefit for unplugging the wfco, you won't have to listen to its fan speeding up and slowing down every time you turn something 12v on or off. the magnum's fans don't come on until you're running at least 100A dc through it.

    just remember to disconnect the wfco from both the AC and DC parts of your power box... even with the AC disconnected, my wfco would power itself up from the DC fuse panel and the fan grinding away, ugh!
  • ahamade's avatar
    ahamade
    Explorer
    Mar 12, 2014
    Ahh ok got ya, so I would take the output from my auto switch box and put that as the 120V into my inverter then the output from my inverter would go into my current WFCO AC/DC panel. I would then disconnect the DC portion of my WFCO panel by say leaving the Converter breaker in the off position. That sound about right?

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