AC Power to Inverter and then to Subpanel in a 5th Wheel

mjammersc · March 2016

I am wrapping up a couple last minute details before I start my solar install on my 5ht whel. I am using a Magnum MS2812 inverter and was wanting to feed it in their "dual in-dual out" config where you route 2x30A breaker/feed into the inverters transfer switch circuit and then it routes the 3x30A to the sub-panel. My 50A power center can't handle more than a 20A breakers per spec so I am looking at options. One is setting up a new main panel setup that can handle the 2x30A breaker and moving my AC breakers to this panel and then feed the inverter/sub-panel circuit from there. I was wondering if there was any other options/suggestions to reduce the amount of rewiring and space taken up by putting in 2 AC panels (new main and a sub). Is using two 2x15A dual breakers, one on each leg of the power center to feed the inverter circuit, tying each 15A pair together to create the two 30A legs at the inverter, a viable option? Another thought is tying into the main 50A incoming and running into something like a MidNite BabyBox with a 2x50 or 2x30A input breaker and then a 2x30A out doable? Other ideas?

Thanks

mjammersc · March 2016

FYI if it matters, the power center is a Progressive Dynamics PD4575

BB. · March 2016

My first question is do you need that much power? What type/AH of 12 volt battery bank do you have? How many Watts of solar panels? Do you plan on long periods of dry camping? Winter/Summer?

Pulling 2,800 Watts from a 12 volt battery bank would use around:

2,800 Watts * 1/0.85 inverter eff * 1/10.5 battery cutoff = 314 Amps (sort of worst case)

And you would need a flooded cell battery bank of ~ 1,120 AH @ 12 volts minimum to supply anywhere close to 2,800 Watts for a period of minutes to an hour or so. AGM or Li Ion type batteries would do better on surge--But it also depends on how long you want to run those loads (I.e., 1,000 Watts for 4 hours or what?).

-Bill

mjammersc · March 2016

My system is 3 285W panels, 6 Trojan T105REs (675AH total) and a Tristar MPPT 60 charge controller. The 2800W inverter was for peak usage spikes vice any long term continuous use as the 2000W didn't provide the margin I felt comfortable with. Estimated daily use is in the 200-250AH range depending on season without conserving. For the Midwest area where I live/camp, that is replenishable on most days and as I migrate west more vacationing, it improves.

scrubjaysnest · March 2016

I'm not sure I follow what you are attempting to do. It appears you want to power the 5'vr entire 120 vac system from the inverter.
There should be no reason you can't feed a 30 or 50 amp load center but you will only have about 23 amps from the inverter (2800 watts/120vac). The transfer switch should be able to handle that when switching from shore power to inverter output. The problem I see is someone overloading the system, microwave plus hair dryer on at the same time for example. Then there is the refrig; if it's on propane not a problem but what I saw in the Everglades with a large Class A amazed me. The CG lost power and the refrig defaulted to inverter power rather the propane. The amp draw was 67 amps DC with just the refrig and a large screen T.V. And the guy couldn't understand why he had to keep running the generator. Nobody was watching the T.V. by the way.

mjammersc · March 2016

I guess I'm not explaining the question well enough. I am not trying to power the whole rv. All the normal high draw items; AC, water heater, washer/dryer (if I ever install one), etc. will all be on a main circuit powered only by external power. The lower draw circuits will be on a subpanel fed by the inverter. The inverter also takes an AC feed off the main circuit panel and runs thru a transfer switch internal to the inverter and when powered would drive the subpanel. My question is the optimal way to feed this circuit from the main to the inverter as the main panels individual breaker size limit is too low to sufficiently power this pass thru circuit. I am trying to see if anyone has ideas on the best way to drive it via either combining multiple breakers or creating s new main panel that can drive it or ???

BB. · March 2016

The normal way of doing this is to setup a second subpanel+breakers that is powered by the AC inverter for the circuits that you want to be battery backed.

-Bill

vtmaps · March 2016

BB. said:

The normal way of doing this is to setup a second subpanel+breakers that is powered by the AC inverter for the circuits that you want to be battery backed.

I think he has a subpanel for his loads. The subpanel will be powered by the inverter. The inverter sees the main panel and when the main panel is powered (by shore or generator) the inverter will pass through power to the subpanel.

mjammersc's problem is that his 50 amp main panel only has 20 amp breakers and the inverter can draw (or pass through) more than 20 amps. He wants to know how to get more than 20 amps out of his 50 amp main panel.

--vtMaps

mjammersc · March 2016

Yep what vtMaps said. Ideally I'd pass through two 30a legs to the inverter. I think I'll just pass through two 20a legs from the main panel and use it for a while to see if I run into any usage limitations which I'm expecting will be rare.

scrubjaysnest · March 2016

Since your already planning a sub panel just parallel feed from the shore power input at the main panel to a 30 amp in the subpanel that becomes the main for the sub panel buss.

AC Power to Inverter and then to Subpanel in a 5th Wheel

Comments

Categories