Large RV system diagram check

[cinergi]

Hi all!

I live full time in an RV and like boondocking, except for running the on-board generator 5 hours a day to recover my AGMs. I have a new 5th wheel being built for various reasons ... so I'm taking the opportunity to "do it right" with this one. It's a custom-built unit, so I'm making sure the roof is as clear as possible for panels and I have conduit and whatnot to run the wires where I need them. It will have true 240 split phase electrical to power the mini split. I intend to run the mini-split while boondocking and I don't want to think about how much power I have or trying to save power... so that means a big system. I'm in a group buy for 32 280Ah cells to make 2 48v banks. I should be able to fit at least 4kW of panels on roof - that's TBD. I "never" want to run the generator - you'll see it's not even in the diagram. I might just have a portable that I plug into the shore power input if I get desperate.

One unique thing about this system is that because I need split phase, I'm using an autotransformer for handling situations when I'm plugged into single phase. I'm also using an autotransformer to effectively load balance the two victron's for the 120v power (so I'm not dealing with overloading 1 leg but plenty of room on the other). The design is inspired by https://community.victronenergy.com...transformer-to-create-120v240v-split-pha.html as well as conversations with another person who's done what I'm doing.

I will be working with a supplier who will also vet my diagram - but wanted to get your input here, too. It's still very much a work in progress. Thanks so much!

 

[cinergi]

The image is being resized on upload - trying to get it larger so you can read it ...
Edit: Fixed

 

[HRTKD]

What is the purpose of the 12v LiFePO4 in the design?

What is the trailer mfg? I've asked two different builders for solar related changes and was basically told to not bother them. I know New Horizons will allow a lot of changes.

 

[cinergi]

The 12v battery is to handle the large 12v loads that the orion (30amp) can't. I don't yet know how much operating the jacks draws but it's far more than 1 and probably more than 2 orion's can handle. But I am debating paralleling 3 orion's instead of having a 12v battery. That gives me 90a (120 spike) of 12v... assuming that's enough for the jacks.

It's New Horizons. They'll do a lot, but not this. They'll accommodate me in terms of having space for the batteries, victrons, breaker panels, and running conduit where I want it... and keeping the roof clear. So I'll get a bare bones battery & inverter system from them which I'll replace with my setup OR we'll find an integrator near them which will implement this plan. The rig won't be ready until January so I have time ...

 

[HRTKD]

I understand about wanting to handle the 12v load. I'm splitting my system so that the generator gets its own battery and doesn't draw on the LiFePO4 bank. It's likely overkill, but I'm not yet comfortable with turning everything over.

I have no experience with 50 amp systems, so I can't help with that.

 

[mckennab]

What size is your mini-split?

 

[cinergi]

What size is your mini-split?

I believe it's 18k with two 9k cassettes. LG. I haven't nailed that down yet

 

[mckennab]

What size solar panels are you looking at? I found that with my footprint it was better to go with smaller 100W panels to squeeze the maximum power from roof space on my (much much) smaller RV concept. This would also allow more options for longer series strings to optimize voltage/current limits of mppt/cables.

 

[cinergi]

420 watts but until I know the roof dimensions and extrusions, that's not been locked in yet. I will have very few obstructions on the roof (e.g. no air conditioning or satellite) so I should be able to really go nuts. I'm actually trying to avoid series strings (within reason) to avoid problems caused by shading. I should have basically free access to ~37 feet by ~8 feet of roof.

 

[HRTKD]

I'm running Mission Solar 320W 60 cell panels. They are mounted within less than 2" of the edge of the roof, with a vent in between each panel. Don't forget that if you use Z brackets for mounting that you'll need about 1.5" wider than the panel on each side of the panel. I don't think you could get much closer with strut, but I haven't done a strut install so it might need less width.

I have a toy hauler, which is the maximum width trailer I believe.

 

[mckennab]

I'm running Mission Solar 320W 60 cell panels. They are mounted within less than 2" of the edge of the roof, with a vent in between each panel. Don't forget that if you use Z brackets for mounting that you'll need about 1.5" wider than the panel on each side of the panel. I don't think you could get much closer with strut, but I haven't done a strut install so it might need less width.

I have a toy hauler, which is the maximum width trailer I believe.

Good info.

 

[cinergi]

I've made some changes - most notably the use of a single 240 Quattro (why have two when they go to an autotransformer anyway?)

The Quattro 10k weighs over 100 pounds!

 

[HRTKD]

I don't know the whole breadth of breakers for PV installations. My breakers are dual pole. Positive on one side, negative on the other. I'm only throwing that out because in your diagram you have only the positive line going into the breaker box.

 

[cinergi]

AFAIK negative cutoff doesn't increase safety / isn't needed.

 

[sparklehunt]

can't see the diagram for some reason...

Edit: nvm you simply have to right click the question mark and download it.

Edit2: @cinergi are you going to update this with your final design with the orion bms? I have lots of questions I think a diagram could answer, thanks!

 

[cinergi]

can't see the diagram for some reason...

Edit: nvm you simply have to right click the question mark and download it.

Edit2: @cinergi are you going to update this with your final design with the orion bms? I have lots of questions I think a diagram could answer, thanks!

The SSR/Contactor "diagram" is here: https://diysolarforum.com/threads/c...w-inverter-rv-build.13786/page-28#post-295848
(I don't have a full BMS diagram at the moment)
The system diagram is here (same thread): https://diysolarforum.com/threads/c...w-inverter-rv-build.13786/page-23#post-233560