Two inverters for 50 amp service

[Cptnvideo]

We have a Go Power IC Series 3000 watt inverter and 50 amp service on our 5th wheel. I have 2 complaints about it that I wasn't aware of when it was installed.
The monitor panel only monitors Line 1. The current limit function only limits current on Line 1. So when plugged into a relative's 15 or 20 amp service, we can only see and control what is being drawn on Line 1. And I would like to control the current on both lines so we wouldn't inadvertently trip the breaker feeding the RV.
Is it possible to have two 2000 watt inverters (one on each line)? My dealer says no. But I don't see why not as nothing in the RV runs on 240 volts.
Correct me if I'm wrong, but to create 240 VAC for two 120 VAC lines, the 2 lines have to be out of phase. And if the lines were in phase, 0 VAC would be measured across the 2 lines. So the output of the 2 inverters would be out of phase when plugged into a 50 amp service and in phase when plugged into 30 (or less) amp service. But I don't see an issue with that. Am I missing something?

[pianotuna]

time2roll wrote:
What? Why are you load controlling? Just feed the beast.

Hi time2roll,

He wants to limit shore power to xx amps so as not to blow shore power breakers. His existing inverter accepts two inputs--but doesn't allow limiting on line 2.

My personal choice would be identical to yours. Get one big inverter to handle all loads, and a 48 volt battery bank.

I suppose a case could be made for redundancy of having 2 inverters.

[time2roll]

What? Why are you load controlling? Just feed the beast.

[Cptnvideo]

time2roll wrote:
Get a single 6kW inverter and feed both sides. Probably need 48v battery. No need to make it complicated.

What?? Why?? I don't think you read the various posts, just jumped in to comment.
I have repeatedly said I simply wanted 2 inverters so that I could control load sharing on both lines of a 50 amp RV.

I still can't control load sharing on Line 2, but I now know how much Line 2 is drawing so I can compensate.

[time2roll]

Get a single 6kW inverter and feed both sides. Probably need 48v battery. No need to make it complicated.

[Cptnvideo]

Yessir, it is a nice product well worth the price when protection is considered. Reviews were interesting with some of the voltage issues discovered at CGs. Wrestling with the 6 ga wire within the small box was a lot of fun. I did as much prepping of the wire as I could outside of the RV before crawling into the space where the transfer switch was located.
Thanks again for the information.

[wa8yxm]

Cptnvideo wrote:
Wa8yxm mentioned the Progressive Industries HW-50C (hard wired surge protection) WITH REMOTE. I decided to look into it.
Well, I purchased one, installed it and I couldn't be happier. It indeed monitors and displays the current on each line.

And you are welcome... Thanks for letting us know how you resolved it as well That product (The HW-50C) can save you a lot of grief in other ways as well.

[Cptnvideo]

Wa8yxm mentioned the Progressive Industries HW-50C (hard wired surge protection) WITH REMOTE. I decided to look into it.
Well, I purchased one, installed it and I couldn't be happier. It indeed monitors and displays the current on each line.

GoPower confirmed that my IC3000 only monitors and controls current on line 1 (which I find to be a poor design since the inverter passes and/or feeds both lines of 50 amp service).

So now if I'm plugged into 15, 20 or 30 amp service and want to use more than the supplied current (load share using solar & batteries), I can monitor the current draw on Line 2 and subtract that amount from the shore breaker size. That would be the amount that I would limit Line 1 to.

Problem solved and I am no longer interested in replacing my 3000 watt inverter with 2 2000 watt units.

[Cptnvideo]

StirCrazy wrote:
My qyestion is why? why not buy one inverter big enough to run what you want to run and use a transfer switch and it will power everything in the RV.

I already have that. But it doesn't have monitor and control of Line 2 like I want.

[StirCrazy]

My qyestion is why? why not buy one inverter big enough to run what you want to run and use a transfer switch and it will power everything in the RV.

[Cptnvideo]

240 VAC is a center tapped transformer. And the 2 legs are 180° phased.
What I want to do does not involve a lot of current, So questions about being in or out of phase are moot.
We have 1600 watts of solar and 618 ah of LFP batteries and likely going to 824 ah in a couple months. And what we want to do is use some of that solar/battery power to augment what we get current wise when plugged into 15 of 20 amp service.
Load sharing (for those that don't already know). The IC Series GoPower inverters have a load sharing function. That allows the user to limit shore current (but only on Line 1) and any additional demand is made up by the batteries. (This is a great feature for anyone with solar and paying for metered electric at a RV park.)
The GoPower IC Series inverters have pass thru for 50 amps on each of 2 legs. BUT they only monitor and control current (load share) on Line 1 (which seems pretty dumb to me). So my plan is to replace our 3kw inverter with two 2kw inverters. line 1 to Line 1 (which is the monitored/controlled line) of one inverter, line 2 to line 1 of the 2nd inverter.
When we are plugged into a 15/20 amp source, we want to ability to use a few additional amps if we want to. In other words, about 60 to 100 ah out of the batteries. So the inverters would pass thru about 80% of 15 or 20 amps and produce a few more amps from the batteries.
I hope this clears things up. Cost is not an issue, looking for convenience. And using some of that excess solar power on a hot afternoon day.
BTW, in response to the 50 amps on the neutral - when we are plugged into 50 amp service, the inverters would be in full pass thru.

[ktmrfs]

CA Traveler wrote:
This is where I disagree. The 50A 120/240V circuit is single phase . The transformer secondary winding is center taped for the neutral and the current flows in the same direction in both halfs at a given point in time. And the neutral current is the difference of the two hot legs. The simple fact that it's a single transformer winding means that it's single phase.

I don't disagree, I'm not saying it is a 3 phase circuit, just that the currents in each leg (and also voltage) are phased 180 degrees with each other so if the current in the neutral is then the difference in current between the legs.

[Cptnvideo]

Larry, I have a 3500 watt inverter generator. You're totally missing the point.

[larry_cad]

It just occurred to me that you could accomplish the same end by getting a Honda generator that will run the A/Cs. It would be more flexible, probably cheaper, and certainly easier and simpler than what your are attempting. If you are concerned about air quality, and probably no worse than the 15/20 amp municipal electricity. And, since you seem to have an affinity for complicated creations, get two smaller Honda generators instead.


:B

[CA_Traveler]

This is where I disagree. The 50A 120/240V circuit is single phase . The transformer secondary winding is center taped for the neutral and the current flows in the same direction in both halfs at a given point in time. And the neutral current is the difference of the two hot legs. The simple fact that it's a single transformer winding means that it's single phase.

[ktmrfs]

Cptnvideo wrote:
ktmrfs, doesn't your current example apply to any 50 amp RV without an inverter?
What is the difference between with and without an inverter as far as neutral current applies?

first question, yes applies to any 50A connected to shore power

The current with inverters is a more complex calculation
My initial thoughts.

with ONE inverter, connected to one leg neutral and hot currents are equal. Two or more inverters on one legs in phase same thing.

Now with two inverters, one on each leg one needs to know the phase relationship between the two inverters to determine neutral current.
If they are in phase then the neutral current will be equal to the sum of the current in each hot leg. If they are 180 degrees out of phase like a normal 240V set of legs, the neutral current would be the absolute value of the difference between the two hot legs.

Now assuming the inverters don't either sync in phase or 180 out of phase, one gets into complex math to determine the current in the neutral and to calculate the current one would need to know the phase difference and then do the complex math to determine the current.

My opinion. If one connects inverters to both legs, unless you KNOW the inverters are synced 180 degrees out of phase make sure the TOTAL of the inverters is less than 50A/6000W or one risks neutral current >50A