RV Electrical System Overhaul - adding inverters!

[cookinwitdiesel]

I think they will just take whatever they receive as long as there is no reason not too. If they are paralleled then you have given them a reason.

Yep, his diagram looks very similar to mine at a fundamental level. It will be an issue with any 50amp dual leg inverter setup unfortunately. Even with the 120/240v inverters out there (Magnum and some others) - how would they act if they receive same phase 120v on both legs? I cannot imagine it would all go smoothly. The problem is that due to the generators and dogbones, we genuinely need a system flexible enough to handle both scenarios gracefully. I COULD reprogram the inverters every time I hook up somewhere, but that would obviously suck. This setup should be good enough and completely hands off regardless of what the input power looks like. Only downside is potentially overloaded inverter on one side and under utilized on the other. But whatever - that is a pretty manageable state of affairs. Again, an autotransformer can help with that IF split phase is present but I am pretty sure that the transformer would get very grumpy if it received same phase on both legs as well!

Fortunately no 240v devices exist in my trailer so it is all academic and not painful to take the simpler route I am planning on.

Ideally, the 2 inverters could be paralleled and they would be capable of flipping the phase as needed to maintain split phase output regardless of input - I am sure such devices exist but that would add cost/weight/complexity to the overall system.

Super duper first world problems haha

[Slowtation]

Hi, I rewired my 303RLS about a year ago. somewhat different than yours. My objective was an "Overnight Walmart Stay" and be able to use all my stuff. This is what I have, One Xantrex SW3012 using two US125 6 volt lead acid deep cycle batteries, a manual transfer switch (I didn't want to use the auto one), 50 amp surge protector, disconnected the "converter" battery charger so to use the SW3012 charger/deep cycle when needed. I have one 30 watt solar charger to keep the batteries alive when parked in storage. If dry camping I also have a Honda 3,000 watt generator/inverter hooked up as a 30amp service only. This setup allows the 50 amps service when in a 50amp service hookup and the rest of the time just a 30amp service, i.e. only use one A/C unit when on the inverter or Generator. All works great! The bad news is that grand Design really didn't follow any kind of color coding one their wiring, makes it real hard! BTW the A/c's have Micro-Air easy start. Good Luck!

[traveldawg]

I think they will just take whatever they receive as long as there is no reason not too. If they are paralleled then you have given them a reason.

Yep, his diagram looks very similar to mine at a fundamental level. It will be an issue with any 50amp dual leg inverter setup unfortunately. Even with the 120/240v inverters out there (Magnum and some others) - how would they act if they receive same phase 120v on both legs? I cannot imagine it would all go smoothly. The problem is that due to the generators and dogbones, we genuinely need a system flexible enough to handle both scenarios gracefully. I COULD reprogram the inverters every time I hook up somewhere, but that would obviously suck. This setup should be good enough and completely hands off regardless of what the input power looks like. Only downside is potentially overloaded inverter on one side and under utilized on the other. But whatever - that is a pretty manageable state of affairs. Again, an autotransformer can help with that IF split phase is present but I am pretty sure that the transformer would get very grumpy if it received same phase on both legs as well!

Fortunately no 240v devices exist in my trailer so it is all academic and not painful to take the simpler route I am planning on.

Ideally, the 2 inverters could be paralleled and they would be capable of flipping the phase as needed to maintain split phase output regardless of input - I am sure such devices exist but that would add cost/weight/complexity to the overall system.

Super duper first world problems haha

Inverters don't care about phases. For that matter, nothing in our simple RV cares (and probably nothing in our simple homes either). It's just simple 120v on each leg and a way to get high current into our RVs/homes. Phasing is something the electric company does to move and provide electricity conveniently. Let's not get started on multiphase transformers!!!

[cookinwitdiesel]

Inverters don't care about phases. For that matter, nothing in our simple RV cares (and probably nothing in our simple homes either). It's just simple 120v on each leg and a way to get high current into our RVs/homes. Phasing is something the electric company does to move and provide electricity conveniently. Let's not get started on multiphase transformers!!!

The inverters DO care about phases in a few scenarios:

1) 2 inverters are running in parallel with a master and a slave, they are programmed to exchange information and configured such that they should operate out of phase - therefore requiring 2 separate legs coming in out of phase
2) a 240v converter is connected to my incoming 120/240v service by just not connecting the neutral. On the output side neutral is provided by an autotransformer that has a ground relay. When the 2 legs coming into that inverter are not in split-phase you now have 0v across the inputs instead of the 240v that is expected. I cannot be certain, but pretty sure this would make things not work

But as noted, fortunately nothing in the RV actually cares about phase as nothing uses 240v power. As such, not being able to properly feed in split-phase power is an extremely minor inconvenience and will not impact actual operation of the RV at all. Hence my decision to just have 2 independently configured 120v inverters, one for each side of the RV.

I have also bought (but not yet installed) 2x EasyStarts for the 2 AirCon units. Those will help when hooked up to the 30amp at home as well as when running on inverters.

[kench2009]

I am considering adding an inverter setup to my Solitude. I am looking at doing 2 inverters so that I can have more capacity as well as a simpler design that will power both legs of the 240v system without any intervention or thought needed. I will want to add solar down the road but initially am just doing inverters and batteries. Adding solar should be pretty simple.

I am looking at Victron MultiPlus inverters which are also battery chargers (converters) as well as automatic transfer switches between the AC input and the batteries (inverter) for the AC output. I considered the Quattros but they would not offer much additional functionality and would complicate other aspects of the design (would allow me to remove the OEM ATS however would require 24v battery bank and then also a 24 -> 12 DC-DC converter setup). I do not currently have any sort of load shedding EMS designed in, that may be something of interest as well (water heater, microwave, fireplace, 2x ACs all as sheddable load if needed).

I considered the Lynx Shunt in place of the BMV-712 and separate fuse but would lose the ability to put a cut-off switch in between the batteries and loads and also already have a BMV-712 I haven't installed yet. I liked the Lynx Distributor on the battery side as it makes it easy to fuse each battery but if I go with lithiums that have a BMS already this could be "downgraded" to the "dumb" version that is just bus bars essentially. There is a very good chance I would have to initially go ahead with a 4x 6V (2s2p arrangement) FLA setup and add lithiums later to spread out the costs in which case some fuses would not be terrible.

I will have EasyStarts on both AC units to allow them to run (albeit for a limited amount of time) without issue.

We have the residential fridge and must be able to power that (not an issue as I will keep the existing inverter in place there) and want to have the flexibility to boondock or spend a night on the side of the road as needed with minimal compromises in comfort/amenities. I know that solar down the road will vastly expand our options, currently the generator can be used to top of batteries between campsites.

I have never done anything like this and have only done a bunch of reading on here so open to feedback and ideas from people.

Thanks in advance!

Wow That sounds like a ton of work and even more expense. Why not consider a generator? very quiet inexpensive to run and by the time you go thru all the trial and error expense with the inverter system and the solar system ( I have solar and a huge amount of storage is required battery wise to run and maintain. )

[cookinwitdiesel]

I already have a generator installed. But it uses propane. I want to use that just for a boost when needed or to top of the batteries if it is not sufficiently sunny out. Solar + Inverters will equal proper freedom

I enjoy the planning and install work, helps me understand the components and systems in my trailer better. And if I was fretting over cost, I wouldn't have bought a top of the line trailer and diesel truck for leisure use This is my hobby currently. The only really "expensive" part is the Lithium batteries, and in the long run they will be multitudes cheaper than a lower cost up front lead acid variant.

[traveldawg]

The inverters DO care about phases in a few scenarios:

1) 2 inverters are running in parallel with a master and a slave, they are programmed to exchange information and configured such that they should operate out of phase - therefore requiring 2 separate legs coming in out of phase
2) a 240v converter is connected to my incoming 120/240v service by just not connecting the neutral. On the output side neutral is provided by an autotransformer that has a ground relay. When the 2 legs coming into that inverter are not in split-phase you now have 0v across the inputs instead of the 240v that is expected. I cannot be certain, but pretty sure this would make things not work

But as noted, fortunately nothing in the RV actually cares about phase as nothing uses 240v power. As such, not being able to properly feed in split-phase power is an extremely minor inconvenience and will not impact actual operation of the RV at all. Hence my decision to just have 2 independently configured 120v inverters, one for each side of the RV.

I have also bought (but not yet installed) 2x EasyStarts for the 2 AirCon units. Those will help when hooked up to the 30amp at home as well as when running on inverters.

I knew that statement was going to come back and bite me.... Whatever.... You set up sounds pretty complicated but you seem to have thought it out well. As they say.... to each his own....

You'll like those EasyStarts. I use one on my main AC unit as my 2 Honda 2000's won't power both (with or without easy starts) and allow a coffee pot, TV and Sat receiver simultaneously without struggling a bit.

[cookinwitdiesel]

Finally installed the EasyStarts last week. No more tripping the 30A at home if I forgot to turn off the AC's before plugging in

I have been working over my complicated design some and it is now....still complicated lol. But I like it more! I think I want to do a 24v system with a converter to step down to 12v for the systems that need it. This will allow for simpler wiring (only needing one instead of 2 for a few things due to lower amperage) and mildly more efficient inverters (like 94 vs 95%). I also think I will use the Lynx Shunt VE.can instead of separate fuse and BMV. I will just need to sell the surplus stuff I already have but it will make the install cleaner and simpler.

I started mocking up the DC wiring for the bus bars, shunt, fuse, and switch and this was what made 24v seem a lot more simple lol.

My big question now is, and I really need input from the RV veterans here, how much 12v DC current should I make sure is available in my trailer? I will need a converter that can handle the load from:
-Water Pump
-Slide motors
-Leveling Jacks and Landing Gear
-OEM Res Fridge Inverter (if I keep it - still undecided)
-Battery heater pads
-Tank heater pads
-Generator starter motor

The OEM inverter is a 1200W unit but from what I can tell, it ONLY powers the fridge, not that entire circuit which includes several other outlets.

I can run 2 of the Orion units in my drawing for 140 amps available (with burst up to 170). They are not too expensive.

I also mapped out all of the breakers in my trailer which was a good exercise.

New diagrams attached.

[carnolddsm]

How much DC current? The hydraulic system will need somewhere between 50 and 80 amps. The generator close to 100 amps.

What am I basing these numbers on? The hydraulic system comes from the factory with a 50 amp breaker, many owners have went to larger wire and 80 amp breakers on Lippert recommendations. For the generator I found a document leading me to believe the amperage draw was somewhere over 50 amps and 100 amps. Tried to measure actual draw with a clamp type ammeter. Initial draw was rather high, dang generator kept starting before I could get a good stable reading.

[cookinwitdiesel]

How much DC current? The hydraulic system will need somewhere between 50 and 80 amps. The generator close to 100 amps.

What am I basing these numbers on? The hydraulic system comes from the factory with a 50 amp breaker, many owners have went to larger wire and 80 amp breakers on Lippert recommendations. For the generator I found a document leading me to believe the amperage draw was somewhere over 50 amps and 100 amps. Tried to measure actual draw with a clamp type ammeter. Initial draw was rather high, dang generator kept starting before I could get a good stable reading.

Ya, I need to crawl around and look at all the fuse sizes. I actually have the electric Ground Control 3.0 system on my S-Class. Part of the challenge in sizing is that obviously, none of these things run at the same time but I would still like to have some sort of buffer. The generator is the big unknown for me since it is currently directly connected to the battery posts and I know that starters draw a LOT of current for a small amount of time.