RV Electrical System Overhaul - adding inverters!

[cookinwitdiesel]

Take a look at the Gopower 3000 Inverter/Charger. You only need one inverter to power both sides of your panel. Simple to wire up and cheaper than two inverters.

The Go-Power IC-3000 is interesting in that it does appear to handle both sides of a 50A 240V service (albeit not equally, several features are only available on Leg 1 from what I have seen). That being said, it is still smaller capacity than I would prefer for going with a single inverter and cost the same as a Victron MultiPlus 3000 which is extremely well regarded, and very feature rich. Reading the documentation for the GoPower made me go back and review what I could find on the larger Victron options (Quattro series) but it does seem they are limited to a single 120v leg as best as I can tell which is a shame. A single 5k or 8k Quattro could work great if it handled both sides well.

I considered rigging it up so that both sides of the AC Panel would get electrified by the same 120v feed (similar to what the 30->50 dogbone adapters do) but the issues comes with the ATS functionality and how would it switch back to proper operation when shore power or generator is used? I would need an ATS with 2 inputs AND 2 outputs where I could manipulate one of the outputs to share the one feed on both legs and it just seems like it gets very messy very quickly, even if it can be done at all.

[cookinwitdiesel]

It seems like the Smart ATS from AM Solar is the only product that really addresses the 240V 50A issue (besides the GoPower) but as far as I can tell, it cost almost as much as the 2nd inverter would anyways (at least $5-600 of the BOM for their kit based on what else is included). So with my design, I have more capacity and less ambiguity in the design (their Smart ATS would be a "black box" functionally which is not ideal for troubleshooting). At least that is where my head is at right now.

[traveldawg]

So, for those of us less informed on all these matters, all this looks terribly complicated.....

Why are so many Distributors needed? Specifically, why use #1 just to connect batteries to #2 ? Is it just to connect batteries? Can't you just interconnect the batteries and have one cable to connect to the inverter(s)?

8 batteries + generator + 2 inverters + solar panels + cabling = have you weighed all of this? Have you priced 8 lithium batteries?!!! - Don't tell the DW about that cost.

Why not just use one 2 phase inverter (maybe like a Magnum 2800)? You get just as much power with less wiring (weight!).

Why a separate inverter just for the frig?

Would the converters from 2 separate inverter/converter's compete with each other over which is charging the batteries? How can they manage the multistage charging simultaneously?

Cookinwitdiesel, it's just my opinion (probably thousands of those here.... and I'm not trying to crash the ideas)... but trying to run ACs off of batteries? - I don't think even the most expensive motor homes don't try that - that's what a generator is for. just sayin'.... this looks way over complicated for running a 5th wheel. Maybe just run the genie a bit when the DW wants to dry her hair or use the microwave or AC.

Anyhow - it is still a nice set up. Maybe I was overthinking your planned arrangement. I just went with 4 AGMs (Sam's club) and a 2000W Xantrex inverter/converter. So far so good using Honda 2000i's for recharging batteries & ru(with Micro start device).

[cookinwitdiesel]

Sorry, I know I am posting a lot but just learned something that I think could be a solution!

Have a single 230V (60 Hz?) inverter output to an autotransformer that will convert single phase 240V to dual phase 120V and load balance between the 2 legs as needed. Has anyone heard of anything like this?

I think I have it figured out although the issue is on the shore line connection going into the inverter (no need for OEM ATS with a Quattro), if a dogbone adapter is used and you have the same single phase 120V on both legs, it wont feed the inverter right (difference between black and red would be 0V compared to ground instead of 240V). If it is plugged into a 50A post, you just connect the neutral to ground and feed over 240V to the inverter and it is fine but the other times will be a problem - not an acceptable end state to me (for example, with the 30A in my driveway where the trailer spends most of its time).

Which makes me think the dual inverter setup is still the best solution. Just treat the whole AC side as 2 separate parallel out-of-phase 120v systems pretty much. They only meet at the RV panel and at the shore power hookup/generator. The 5000VA quattro cost more than the 2x 3000VA MultiPlus and would have 800w less continuous power available as well as requiring an additional $700 for the autotransformer. Making the dual inverters seem like the obvious path forward to do what I want.

Does that make sense?

[traveldawg]

Sorry, I know I am posting a lot but just learned something that I think could be a solution!

Have a single 230V (60 Hz?) inverter output to an autotransformer that will convert single phase 240V to dual phase 120V and load balance between the 2 legs as needed. Has anyone heard of anything like this?

Actually the 240v you are referring to is really 2 120V legs. That's what gives 240v. Each leg is rated at 50 amps. So you really wouldn't need anything to convert it to dual phase - it already is. If you take the 50a (2 leg service):
> into a proper power protector like an EMS-HW50C (I prefer the hardwired version);
> pass that into a normal type transfer switch (which I think you have installed assuming you have a generator installed already);
> and pass that into a single dual phase (2 leg) inverter (I'm mostly acquainted with Magnum 2800w inverter/converters coming from a motorhome past);
> you then have a 2 phase, 50 power to send to your existing power panel.

You can get the associated Magnum remote to manage things (including remote gen start if your gen is so equipped), charge batteries, etc.

Things may get complicated at this point concerning the power panel distribution. The ones GD uses doesn't really allow for separate inverter circuits and non-inverter circuits (thus a dedicated frig circuit tied directly to their original, dedicated to the frig inverter). Assuming you don't want the entire RV on the inverter you would have to use a sub panel for inverter circuits or remember not to run the Acs while on inverter.

I think I have it figured out although the issue is on the shore line connection going into the inverter (no need for OEM ATS with a Quattro), if a dogbone adapter is used and you have the same single phase 120V on both legs, it wont feed the inverter right (difference between black and red would be 0V compared to ground instead of 240V). If it is plugged into a 50A post, you just connect the neutral to ground and feed over 240V to the inverter and it is fine but the other times will be a problem - not an acceptable end state to me (for example, with the 30A in my driveway where the trailer spends most of its time).

Which makes me think the dual inverter setup is still the best solution. Just treat the whole AC side as 2 separate parallel out-of-phase 120v systems pretty much. They only meet at the RV panel and at the shore power hookup/generator. The 5000VA quattro cost more than the 2x 3000VA MultiPlus and would have 800w less continuous power available as well as requiring an additional $700 for the autotransformer. Making the dual inverters seem like the obvious path forward to do what I want.

Does that make sense?

Sounds waaayyy too complicated. See my first comment regarding how this actually works (240v dual phase). I just think a single inverter is much simpler. You just feed 2 phase in and get 2 phase out without managing, maintaining, repairing 2 inverters. oh - when you get to a 30a campground site you use a 50a to 30a adapter and forget it - things work normally, you just have 30 amps total into the RV and everything is on one phase.

[cookinwitdiesel]

So, for those of us less informed on all these matters, all this looks terribly complicated.....

Do not feel bad, all valid points

The multiple distributors are essentially just fancy bus bars that will look pretty together. Each one is like getting 2x 1000A bus bars in a $130-$200 package which is about as good a price as I have seen elsewhere. On the batteries, if running them all in parallel, this is the best design for perfectly balancing them (as long as all wires are the same length).

The generator is there regardless of the rest, so its weight is a non-factor. As for the rest, I know it will add weight - I would guess in the range of 500# total at most. Right now I am kind of designing my dream system, I expect reality to land somewhere between that and doing nothing, but I can learn a lot on the way. Lithiums help with weight vs FLA BUT hurt the wallet considerably more. Price was where I lost the wifes interest haha.

The fridge inverter is already there, that would be just moving its 12v source from current lug to a different spot and otherwise not touching that wiring. I could just run that much smaller inverter when traveling and not have the overhead of the larger ones. It is just the OEM WFCO unit, if/when it dies, I can re-design that into the rest of the system (if there ever is a "system" haha).

The 2 inverters would charge the batteries in parallel, my assumption is they can be programmed to work in sync so there would not be a conflict - Victron advertises putting them in parallel for greater charging and AC output.

As for running the air conditioners, you make a painfully obvious and valid point, I am way off the deep end with unrealistic ideas here haha. I need to map out all of the AC circuits properly in my trailer similar to what Howson did and identify what my best options are. Probably a simple single inverter powering half my panel with some Costco batteries lol

I was not aware of the split phase Magnum models, maybe just throw that in, remove the Color Control GX (and save another $500) and call it a day. Use the trailer (minus the high draw stuff: water heater, ACs, microwave) and be on my way! I see they have many different model lines, is there one that has both the hybrid/power assist capability, a built-in ATS, AND the split phase capability? That would be ideal I think for the RV use case.

[cookinwitdiesel]

Actually the 240v you are referring to is really 2 120V legs. That's what gives 240v. Each leg is rated at 50 amps. So you really wouldn't need anything to convert it to dual phase - it already is. If you take the 50a (2 leg service):
> into a proper power protector like an EMS-HW50C (I prefer the hardwired version);
> pass that into a normal type transfer switch (which I think you have installed assuming you have a generator installed already);
> and pass that into a single dual phase (2 leg) inverter (I'm mostly acquainted with Magnum 2800w inverter/converters coming from a motorhome past);
> you then have a 2 phase, 50 power to send to your existing power panel.

You can get the associated Magnum remote to manage things (including remote gen start if your gen is so equipped), charge batteries, etc.

Things may get complicated at this point concerning the power panel distribution. The ones GD uses doesn't really allow for separate inverter circuits and non-inverter circuits (thus a dedicated frig circuit tied directly to their original, dedicated to the frig inverter). Assuming you don't want the entire RV on the inverter you would have to use a sub panel for inverter circuits or remember not to run the Acs while on inverter.



Sounds waaayyy too complicated. See my first comment regarding how this actually works (240v dual phase). I just think a single inverter is much simpler. You just feed 2 phase in and get 2 phase out without managing, maintaining, repairing 2 inverters. oh - when you get to a 30a campground site you use a 50a to 30a adapter and forget it - things work normally, you just have 30 amps total into the RV and everything is on one phase.

I understand the 120/240V stuff just fine (I actually got my degree in Electrical Engineering). I call it 240V when there are the 2 hot legs out of phase with 240V between them. You only have 120V relative to neutral, in my autotransformer idea, the neutral is no longer present and a 240v inverter is used - that was the issue with the dogbones but I have already kind of moved away from that idea due to the challenges at the shore power side of things. If you look in your house at a 240v appliance (something that does not need any 120v, it will not even use the neutral, just hot1, hot2, and ground). Usually this would be the heat element side of an oven or dryer (the control board is still 120v). My residential heat pump is a strict 240v, just hot1, hot2, ground, there is not even a neutral present.

I need to search more on split-phase inverters, I did not realize they were really a thing (I am guilty of having Victron blinders on since I really like their quality, design, and ecosystem - but apparently they do not care to do a split-phase model). Thanks for pointing them out to me!

[traveldawg]

Sounds like you have enough to think about already, cookinwitdiesel. I find myself sitting here this morning catching up with things on line. I really wasn't planning on getting so in-depth with all this but maybe it gave you something(s) to think about.

Like I said, my previous rig was a class A with a magnum 2800w inverter/converter and remote panel. It came that way and given how many things I upgraded or 'moded' on that rig, the AC distribution & stuff was left alone except for the hardwired EMS. It served me well. It came with 6, 6v batteries which, when replaced, I went with Lifeline AGMs.

With my current rig I went real simple with 4 AGMs, 2000W inv/conv, and put the frig and all 120v receptacles on that except fireplace. It works OK. I think I mentioned I used my Honda 2000i's the other night for dry camping & everything worked OK. Somewhere on this forum I have a post about that mod (the inverter/subpanel, etc.). If I dry camp more I'd add solar & Victron BMV-12 & maybe change to Lithium batteries.

[cookinwitdiesel]

Here is a more practical version I have worked up, only one inverter for now on one hot leg, I can add a 2nd down the road if desired for the other side. Wont try to run AC on inverters (although technically could) since there is no way to have enough battery for this to be at all practical - I have a generator for those times

I was reading online and it appears that the dual inverter route is the most common way to solve the 240/120 problem for folks who want to use Victron gear. I would just need to program them to run in parallel and 180 degrees out of phase. This way they would play well with shore power passthrough when plugged in. It will however present challenges with power through the generator or dogbone adapters since they are same phase on both legs, so one of the inverters will not get what it is expecting and will run from DC power and disregard the incoming AC power. The generator can be fixed with an autotransformer if I go the 2nd inverter route some day so then only would be in a weird mode with dogbone connectors - at my driveway at home but pretty much never any other times. And I will probably just get a proper 50amp at home - the cable is already there - just have to fix stuff at the panel end and put on a new receptacle.

I have already ordered the parts in the grey box and will start figuring out what it will take to install them in the near term. Should be able to use that stuff with the existing system and batteries for the time being. I have to chill for a couple months on purchases or my wife will freak out about my RV related spending haha. I am leaning heavily towards the Lithiums since cost is the last concern of mine through all this frankly - I threw in some text that helps make that more clear.

Also, I put a little more effort into learning the solar side of things. Should be able to very comfortably put 6x 180w panels on my roof and get about 81A peak charging into the batteries from that. Solar would happen at a later date either along side the inverter and batteries or as a separate install all together.

[cookinwitdiesel]

I learned today that Victron actually used to sell the perfect inverter for the 50 amp RV use case (and really any North American 120/240v system) but apparently discontinued it

Still trying to work out what my ideal configuration would be.