Magnum 3000w inverter in 50amp system

[Unyalli]

Hello, If I go the expensive route I will install a Magnum MSH-3012-M Hybrid PSW inverter/charger. I would want the ability to run the entire RV (not all at once of course) via this unit so would have to re-wire. Looking at WFCO's manual for the 8950/30 power distribution panel it looks like the right hand 50 amp breaker powers the breakers to the right of it and the left hand 50 amp breaker powers the breakers to the left of it.


I would have to switch the GFI and water heater so all my outlets were on the right hand 50 amp breaker. Next replace the full width 20 amp breaker for the main air conditioner with a double 20 like the ones way over on the left and reconnect the Ac to one of the new 20 amp breakers and move the micro to the other. Now I would have everything I will ever use on the "red leg" and would wire it through the inverter utilizing it's built in 60 amp transfer switch. Sound about right so far?





I would have all the left hand breakers off all the time as I would not use any of that stuff. I all ready have the ac plug from my refrigerator unplugged so it can never run on ac. The magnum manual states "The AC input and output neutrals must be isolated from each other, do not route the AC input and output neutrals to a common neutral bus." When I take the red leg loose from it's 50 amp breaker and extend it to the inverter with a length of 8/2 wire I would connect the neutral of this new wire to the neutral bus in the picture and the ground to the ground bus. Now with a second new length of 8/2 I would connect from the inverters ac output with the hot (black) going to the right hand 50 amp breaker but where will the neutral go?

Jeff

P.S. I will never try to draw a continuous 3000 or even 2000 watts from my batteries.

Moderator edit to re-size pictures to forum limit of 640px maximum width.

[tahiti16]

Make sure you isolate the neutral and ground buss bars from the metal case or the will still all be tied together.

[diveman52]

Ain't gona work
That inverter has a double pole double through transfer switch buildin
The contacts are only rated 30 amps. When you switch over to the inverter it just jumps A & B phase together on the load side so you only get 120 volts period.
Running the AC off it LOL how many batteries to you intend to carry.
I'd suggest at least 4 Trojan L16H might get a few hour out of it.

I just finish a project on a house boat with solar and a 4000 watt Magnum MS-4024
unit with 8 Trojan L16H. They only run around $275 each and up.

I suggest you talk to someone who really know what there doing.

[Unyalli]

GordonThree wrote:

Unyalli wrote:


Oh ya, if I go this route the existing converter/charger get's unplugged right away just like my fridge is already unplugged.

Don't forget to disconnect the DC (output) side of the old converter too, eliminates a parasitic load off your new system.

Will do

[GordonThree]

Unyalli wrote:


Oh ya, if I go this route the existing converter/charger get's unplugged right away just like my fridge is already unplugged.

Don't forget to disconnect the DC (output) side of the old converter too, eliminates a parasitic load off your new system.

[Unyalli]

I see what I was missing, thanks guys. I need to split the neutral and ground bus bars. I have to split the ground as well as neutral because in a RV the ground and neutral are tied together.

I can remove both bus bars and cut them in half removing an additional 1/4 inch from one of the halves. When reinstalled there will be a 1/4 inch gap between them and I could epoxy a chunk of plastic of some type in there to ensure insulation. Now I have converted my power distribution panel so one side is a sub panel no?

Now I reconnect all the AC circuits with everything to the left hot, neutral, and ground connected to the left and same for the right. I connect the incoming shore neutral and ground to the left side bus bars. Next I take the right hand hot leg red wire loose from it's breaker and extend it to the inverter using a new length of 8/2. I connect the neutral and ground of this new wire to the left side bus bars. Finally with another new length of 8/2 I connect the inverters output to the right hand breaker and bus bars.

Now if I ever connect to a true L1 L2 50 amp pedestal the left side will have power and I could turn on the breakers powering the things I want like maybe the hot water heater. I really don't believe I would turn anything else over there on maybe the fireplace just to show off.

Jeff

Oh ya, if I go this route the existing converter/charger get's unplugged right away just like my fridge is already unplugged.

[BoonHauler]

Just to throw another wrench into the works, I don't think your load center is split (bus wise) the way you might think it is.

It appears to be a (typical) A & B phase bus bar configuration meaning it's A-B-A-B and so on, not A phase on one side and B phase on the other. That's why the main breaker is a two pole breaker.

Edit: You might be right, after studying the manual more it just maybe one side and the other. A simple powered down continuity check will tell.

[BoonHauler]

Jeff:

I'm not quite sure I understand what you're talking about or maybe you've missed the point of the proposed inverter.

In my mind, with the proposed inverter you're going to lose the second leg of the 50 amp service so follow me along here.

I'm assuming from the pix of your load center that you have two hot legs incoming so in reality your 50 amp service is a 250 VAC circuit, correct?

The proposed inverter has only one hot leg (125 VAC) correct?

So for the proposed inverter to handle (all) the TH's electrical loads I'd change the shore power wiring that is now 3 wire (two hot legs & one neutral) to a standard 2 wire 125 VAC curcuit, run it through the inverter as shown in the manual then out to the trailer load center (neutral wire to the neutral bus bar and the hot leg to either one of the 50 amp main breakers and install a (line side) "jumper" from that now hot 50 amp breaker to the other 50 amp breaker).

I think that you need to realize that you are no longer going to have a "50 Amp Service" on your TH.

You're also going to have to change the charging logic of your battery bank as well and again, follow me along here.

If infact the WFCO is converter / charger or there already is a battery charger somewhere in the TH the new inverter which is a 'inverter/charger' will, as soon as it sees shore power, go into charge mode and start charging the battery bank. The inverter will also send shore power through to the house panel that if I'm correct will also start charging the house batteries as well, correct?

When not on shore power and in 'Inverter Mode' the house panel will again be energized and the house charger will start charging the battery bank using the power coming from the battery bank.

This too me may create a condition that may or may not damage either the inverter or converter and you may want to consult with both the Mfg'ers prior to doing any of the wiring mods.

If you would be so kind as to provide the page or section number in the Magnum manual where they're referring to the AC Neutrals that may help us identify what in fact they're referring to but I think it's just saying no common neutral bus meaning the incoming (shore power) neutral must first go through the inverter (as shown in the manual) and then onto the neutral bus bar in the (house) 120 VAC load center (again, as shown in the manual).

[tahiti16]

Unyalli wrote:
The magnum manual states "The AC input and output neutrals must be isolated from each other, do not route the AC input and output neutrals to a common neutral bus." When I take the red leg loose from it's 50 amp breaker and extend it to the inverter with a length of 8/2 wire I would connect the neutral of this new wire to the neutral bus in the picture and the ground to the ground bus. Now with a second new length of 8/2 I would connect from the inverters ac output with the hot (black) going to the right hand 50 amp breaker but where will the neutral go?

Jeff

Where are going to connect the neutral and ground coming out of the inverter? You will need to move the neutral and ground for each of the circuits you are going to run off it to the same neutral and ground as the whole circuit has to be completed.

Easiest way if you can put a small sub box near the current box is feed out to inverter and then into new box and just move the circuits you want powered by the inverter there. You could use the slot that was powering the a/c and micro for a breaker that feeds out to the inverter, this is the way my Dolphin is wired from the factory.

[pianotuna]

Hi,

Two of these would work to power a 50 amp RV: Outback 1300 watt

To stack units, you need the OutbackMATE (~$230) and the OutbackHUB (~$150 for the 4 port).

[Unyalli]

GordonThree wrote:
Jeff, Interesting problem - I guess Magnum wants you to buy two inverters to run a 50a trailer huh? What a PITA!

Only if you want both legs. I don't. I bought this rig because it was the only fifth wheel toy hauler out there within my weight restrictions. The two major draw backs with this rig are the 50 amp service and that asinine cougar touch panel. We can never have everything we want.

GordonThree wrote:
I wanted to be able to run the AC in a pinch if things got really hot.

I live and camp out west usually above 6000ft altitude. All though we see 95 degrees it's never humid so rarely if ever NEED air cond. With this hybrid inverter and the solar IF I need AC I can provide the 1600 watts between my 1500 watt 2000i champion and the 700 watt solar array. The batteries are for the inrush surge when the compressor starts thus the 3000 watt size. In addition to all the left side breakers the AC breaker would be off all the time as well. If I turned the AC breaker on the microwave breaker would go off.

Jeff

In addition if I ever started to need AC more often I would replace that obnoxiously loud and inefficient 15k Dometic with a 13.5k Coleman Mach III PS (not the plus). This way I would only need 1100 watts.

Moderator edit to re-size picture to forum limit of 640px maximum width.

[GordonThree]

RoyB wrote:

You will need to install several batteries in your battery bank to handle this very large load even for just a few hours. Also when you increase your battery bank capacity then you also have to increase your ON-BOARD Charging system to be able to recharge the battery bank in the desired time you want to the battery bank to return back to a usable charge state.

Jeff, I missed that part, is this install going in a motorhome, so an extra alternator or bigger alternator is required?

The Magnum has a 125 amp 4-stage charger, but that only works on shore power, not driving down the road 🙂

[GordonThree]

Jeff,

Interesting problem - I guess Magnum wants you to buy two inverters to run a 50a trailer huh? What a PITA!

I put a separate incoming power panel in a cabinet above my house panel, which feeds the Magnum. Originally I thought I would move my AC and Fridge to it, but decided not to hassle with it. I wanted to be able to run the AC in a pinch if things got really hot.

[RoyB]

Of course what you have described is the so called easy part of your install.

I think your 3000WATT INVERTER will need around 250AMPS DC Current to operate it at full load which has to come from your battery bank. I notice the spec sheet calls for a 400AMPS DC source to be used. This is some serious capacity requirement.

You will need to install several batteries in your battery bank to handle this very large load even for just a few hours. Also when you increase your battery bank capacity then you also have to increase your ON-BOARD Charging system to be able to recharge the battery bank in the desired time you want to the battery bank to return back to a usable charge state.

Alot of planning will be required in this area as well. The only real time example I can offer from experience is I had to load down a 1500WATT Inverter with test equipment on one Antenna field repair test we were involved with back in my working days. All we had was a rental car with it's single probably a 105AH battery in it. We fired up all of the test equipment was wanting to use which just barely added up to a full load of 1500WATTs. They all fired up normal but only lasted about 15 minutes before running the rental car battery down to a full discharge.

1500WATTS operated by a 12.3VDC source would represent around a 120AMP DC LOAD (not counting losses). 120AMPS is half the current load of the 3000WATT Inverter so this would drain the 105AH battery in about 7 minutes all things being equal. If you are wanting to run your trailer setup for 8-10 hours like most of us want to do you are going to need many 12VDC batteries in your battery bank... The manufacture wants you to install a 400ADC battery source which will include larger battery cables and a much larger setup to give you a more reliable system to use.

Just passing along to make sure you are understanding what you may be up against for the 3000WATT INVERTER install.

Roy Ken