Newbie hoping for help on dual Victron Quattro 2x120V RV system install.

[SoggyShoes]

Well here we go!
I have been spending a lot of time searching the internet and especially this forum over the last year and trying to figure all this stuff out. Now I am hoping to get some support in building my own system and, test what I learned from all the amazing discussions on this site.

I have a 2001 class-A 50amp motor-home that has two AC units and a 5,000W generator. The generator can run everything just fine. We have 12V&propane or 120V options for the heat, hot water, and fridge. We do a lot of boon docking or dispersed camping. We mostly need the 120V for the AC units. We have no TVs in the RV and really try use the RV to get away from all the screens except for navigation and in planning our next leg of the adventure.

Like everyone, we want it all, but have limited resources. So, I need to find that balance of providing what we need now with the best options to accommodate any future upgrades. We do not like hearing a generator at night and want to be able to run at least one AC unit when sleeping and driving without a generator.

I feel what would best in terms of need vs wants vs money is a system based on two Victron Quattro 24v 2x120V inverter/chargers. If money were no object, it seems the twin Quattro 5000/120V would be best, but I am pretty sure our current load usage will be fine with the two 2x120Vs. I realize this may change if we switched to a residential fridge, add kitchen appliances, or whatever we need to add that will keep our daughters wanting to go on trips with us.

I am planning on going with 24V because the Victron 2x120V units currently only have 12V or 24V models. Also, this would allow me to use Victron’s 24-12 smart charger for charging the house and chassis batteries and leave the 12V house system alone. It does not look like they make a 48-12 charger. I also am thinking of going 24V because the 48V batteries would be very heavy to manage. My plan is to build four 304Ah 25.6V batteries using EVE LF304 Grade A Cells. With 24V, each battery would be about 100 pounds, which is heavy but I could handle, but 200-pound 48V batteries are going to be a challenge.

So given all that, here is the system I have come up with. As a newbie, I would really appreciate any suggestions, support, and constructive criticism that will help me do this correctly. Hopefully, I will earn my stripes and be part of this really cool club!

 

[justinm001]

Couple things. 48v batteries aren't any different size/weight than 24v. If it's twice the weight it's twice the capacity.

Why 3 shunts? The lynx shunt is going to be the main one and the batteries will drain together. I'd kinda suggest the smartshunt or bmv over lynx. I have all 3 and lynx looks nicer and has vecan over the stupid vedirect that I have to superglue but no Bluetooth so if an issue you can't just check that separately.

Not sure if you'll be able to have a shunt on the chassis battery. Engine starter loads usually are over the shunt limits. They do make a 2000a one but I wouldn't risk it. You can use the smartshunt aux input to monitor chassis voltage which is really all you need.

Is the chassis battery Orion charging the chassis or for the alt to charge the lfp system? Doesn't make sense to charge the chassis you can just use an ac charger since you'll only want to charge when on shore. If using for alt, see how many amps you can pull from the alt. It's very nice to be able to pull 1500w to run an ac while driving without losing any battery.

But if for alt wouldn't you want to have it on your house system? Most RVs connect chassis and house together when running so better to run chassis to house to lfp system. This way if it over pulls amperage it'll use both banks as a buffer and not affect the chassis.

Whats that rotary changeover for?

 

[SoggyShoes]

justinm001,
Thank you so much for taking the time to look over my diagram! From what I can see, your system is awesome.

.....48v batteries aren't any different size/weight than 24v. If it's twice the weight it's twice the capacity.

It is not about the overall weight. Two 48V batteries will way the same as four 24V batteries. It just seemed that dealing with four 100 pound batteries would be easier to handle and move than two 200 pound batteries. The bigger reason is that the Quattro 2x12v (or Multiplex) only come in 12V and 24V options. As I said my 5000W generator can run everything so it seems that two 2x120V inverters will work and is half the price of the two Quattro 5000V, like what you have. As of now, the Quattro 2x120V do not come in 48V.

The biggest screw-up is that I realized that I had them in series instead of parallel! Oops! I fixed that.

Why 3 shunts? The lynx shunt is going to be the main one and the batteries will drain together. I'd kinda suggest the smartshunt or bmv over lynx. I have all 3 and lynx looks nicer and has vecan over the stupid vedirect that I have to superglue but no Bluetooth so if an issue you can't just check that separately.

This is just highlighting all that I still don't know.
I saw some diagrams where each set of batteries had a manual shut off and a smartshunt for monitoring that set of battery banks. I know the BMS's bluetooth will let me see this. I was thinking the shunt would be needed so the Victron products see the battery levels and act accordingly. Looking at the Victron site, it seemed that the Lynx shunt was part of the Victron Lynx busbar system and gave the "smart" features to the busbar.
If I only used one shunt for both sets of batteries, where would it go? I thought the BMV series was just a smart shunt but with a temp sensor and a separate display. I didn't think the BMV series wan needed if I have the GX display.
If the Lynx looks nicer and has the vecan, why would you prefer the smartshunt or Lynx over it. Is it because you would rather have bluetooth than the either of the wired communications?
Does the vedirect not work that well?

Not sure if you'll be able to have a shunt on the chassis battery. Engine starter loads usually are over the shunt limits. They do make a 2000a one but I wouldn't risk it. You can use the smartshunt aux input to monitor chassis voltage which is really all you need.

Yes, all I was trying to do was monitor the battery levels. I thought it would be nice to have everything all in one on the GX display.

Is the chassis battery Orion charging the chassis or for the alt to charge the lfp system? Doesn't make sense to charge the chassis you can just use an ac charger since you'll only want to charge when on shore. If using for alt, see how many amps you can pull from the alt. It's very nice to be able to pull 1500w to run an ac while driving without losing any battery.

But if for alt wouldn't you want to have it on your house system? Most RVs connect chassis and house together when running so better to run chassis to house to lfp system. This way if it over pulls amperage it'll use both banks as a buffer and not affect the chassis.

My thoughts on the 24-12 charger on the chassis was first as a charger for the lead acid chassis battery when not in use as well as to maintain a charge in case I wanted to leave the running lights on or something like that. I have nice marine 120V smart charger laying around. I guess I could use that.
I was concerned about going the other way and damaging the engine alternator. It would be really nice if it could support most or all of an AC unit while driving. I will check that out. If that worked, do I need another Lynx power in to connect it?
I definitely don't want to do anything that have a negative effect on the engine alternator or electrical system.

In the future I might add a 24/12 charger for a tow vehicle charger. I am hoping to get a flat tow vehicle in a few years, but for now I changed it so there is only a 24/12 charger for the house battery system.

Whats that rotary changeover for?

I thought I needed it if I was using a 30amp shore power so both inverters had some power. Now I realize that a 30amp to 50amp dogbone does exactly what had the rotary switch in there for. So it is gone.

Are one of these better?


Thanks again for helping me!

 

[justinm001]

The shunt just logs the voltage and how much power flows thru it. Connect the batteries together and put the shunt between the batteries and the load... So right where the lynx shunt is works.

Lynx shunt has no bt but vecan and is 1000a it looks cool connected to the lynx box and does power the lights on the lynx distribution so you can see the bad fuse, although it doesn't tell Cerbogx it's blown which is dumb.

Smartshunt has Bluetooth and 500/1000/2000amp models, also I think the new one is water resistant which is nice. It has the vedirect. Problem with these cables are they don't clip in and there's only 3 ports on the cerbo. I've broken quite a few just tugging on them and many times they wobble off so I've superglue both ends. All the other cables like vecan, vebus are just cat6 network cables so you can grab anywhere and they lock in. Also can buy different colors. Vecan you can daisy chain so have a bunch nice and neat, they just use terminators on the end of the loops but come with them. I just don't like the lynx doesn't have Bluetooth so you can only see info through the cerbogx, so if issues and your cerbo is offline you can't simply login using Victron connect and see the soc, voltage and such.

Bmv is the smartshunt with a little dial. Nice part is the Bluetooth sensor is in the dial as is vedirect port and the dial connects to the shunt using a rj11 (phone cord), so can be a bit easier to setup. It's also nice to have a display just show a voltage. Idk what the buttons do I use just to monitor my genset battery.

You're not going to want to use DC to charge the chassis batteries. You shouldn't ever want to charge them when boondocking and really only want them to be charging when you're on shore which will be on ac. I also feel doing dc-dc is preemptively fixing a problem that you won't know is there. Say your alternator goes out, the DC DC converter will feed power to the chassis and you won't notice an issue until lfp is dead. Same if in storage and key is on or anything else. I use an AC charger connected to a kasa smart wifi switch and use the app to flip it on and charge my chassis batteries when not in use. Cerbo monitors voltage so I get an email if chassis is low then turn it on. It let's me know there's an issue and fix the root cause (wife leaving key on). Plus they make AC battery chargers that charge 12 and 24v and all battery types, so you can keep one in your RV to top off the chassis and if any issues with your inverter you can just plug it into your lfp to charge.

The lynx power in isn't really needed, you can combine the pos and neg on the batteries and save a couple hundred bucks. I also think you dont need 2 distribution ones either. The inverters only need 1 battery wire 4/0 should be plenty for 3000w at 24v. There's an extra port for a ground on it and you can use a separate fuse block on the end to get a 5th wire, even a 6th. I believe there's a youtube on how to. Although they do look nice when setup properly.

You can definitely get some power from the alternator to the lfp system. How much depends on the alternator size and how much is used. They just came out with an Orion XS Idk if it's 12/24 but it should allow you to limit the amperage. Otherwise you just get an Orion that is under the amount of amps you have. I have 6 Orions pulling power from my alt to my house systems. 3000w so I can ru. 2 ACs while driving.

 

[justinm001]

BTW they do make 48v 3000w Quattro inverters.

Not too sure the difference between the Quattro and Quattro2 but it looks like the Quattro2 has less amperage thruput 50a vs100a.

The 2x120 isn't helpful if you're getting 2 inverters. With 2 inverters you'll be able to run 120v and 240v inputs.

I have a feeling the Quattro2 are a lot slimmer. My Quattro 5000s are massive.

Quattro - Victron Energy

Prevent overloading of a limited AC source. Connect the Quattro to two independent AC sources and automatically switch to the active source. Learn more.

www.victronenergy.com

 

[Brucey]

BTW they do make 48v 3000w Quattro inverters.

Not too sure the difference between the Quattro and Quattro2 but it looks like the Quattro2 has less amperage thruput 50a vs100a.

The 2x120 isn't helpful if you're getting 2 inverters. With 2 inverters you'll be able to run 120v and 240v inputs.

I have a feeling the Quattro2 are a lot slimmer. My Quattro 5000s are massive.

Quattro - Victron Energy

Prevent overloading of a limited AC source. Connect the Quattro to two independent AC sources and automatically switch to the active source. Learn more.

www.victronenergy.com

I think he's saying the 2x120V isn't available in a 48V model. I did see the other day a post on the Victron community forums that the multiplus 2 has slightly less surge than the original multiplus 1, not sure if that's also the case going from Quattro to Quattro 2

 

[Rocketman]

Here are a few more observations…

I full time in a MotorHome, have a Multiplus 12/3000 and a 12v 544ah lithium battery (diy). So you will have a little more than 4x the battery that I have.

You will only need 1 set of 4/0 wires going to each inverter. Also to run the air conditioners, you need a soft start on them. I installed a Micro Air EZ start and the startup amps went from 27.4amps to 15.3amps.

I can run my rear Air conditioner for about an hour before I need to shut it off or start the generator- with 4x the battery you should make it through the night.

How much solar are you planning for your house system? I have 1400w and wish I had a bit more.

I recently added a 100w panel and a Victron mppt 100/20 to my chassis battery (took out a small battery maintainer that took power from the house bank). That tells me my voltage on my chassis (starter) battery. I could have used a 50w panel. You could use that idea instead of the shunt on your starter battery.

Also, I added the Victron Smart BP-65 (battery protect) going to my 12v fuse boxes. If my lithium battery is low they shutdown before the Bms turns off. That way loads cannot drive my lithium to bms low voltage shutdown. I would use that instead of the on/off switch between the Distributor and the 24-12v converter. It can also act as a on/off switch too. (I have used it more to reset the power to my furnace than anything else).

You probably do not need on/off switches between the mppt and the distributor- you have a fuse at the distributor and via the app you can turn the mppt off. You will want a on/off switch (or breaker between the solar panels and the mppt, that way you can turn the sun off for maintenance and testing.

Also, a residential fridge is awesome! And they don’t really use much power.

Make sure you plan where all the new Victron stuff and batteries are going. Space it tight in our rigs and remember KISS - Keep it Simple and Serviceable (I am always messing up the Serviceable ).

Good Luck

 

[justinm001]

I think he's saying the 2x120V isn't available in a 48V model. I did see the other day a post on the Victron community forums that the multiplus 2 has slightly less surge than the original multiplus 1, not sure if that's also the case going from Quattro to Quattro 2

Yeah but if OP is going dual inverters the 2x120 is kinda pointless. I guess he could put them in parallel and get 6000w instead of split phase and get 3000w on each leg but it shouldn't matter with his loads.

Looks like the 2 versions have less surge. The 2 versions seem to only have 50a for the 5kw models. But the Quattro 3kw is still only 50a, it's the 5kw that are 100a. This is a huge benefit as with a huge load coach like mine I can hook up to 50a shore and power assist to get above 50a. Also I have a 20kw genset which is 80a. Nice for my 6 AC units when cooling the rig down before a trip.

 

[justinm001]

Another thing. If your battery BMS communicate with each other and they communicate with cerbogx then you don't need a shunt at all. It kinda becomes more of a hassle as the BMS is always right on the SoC and the shunts just guess so can be off a few percent and then you see one at 70% and other at 74%.

Also if the BMS communicates with cerbo it'll use this to set the charging voltages and limits on the inverters and solar.

So the reality is you can just put a shunt on your house 12v then use the aux voltage monitor for chassis and let the BMS report the batteries and you're all set.

If the batteries have on/off Breakers I wouldn't add any more. I dont see a point in the mppts in having them either or the DC DC charger. The mppts you can program off on the app and the orions you can just unplug the relay. Actually the mppts you can unplug the relay too. The least amount of connections and devices the better. Less things to rattle loose and less potential for failure.

I also forgot one big benefit of the lynx is it has a fuse spot for the batteries.

 

[SoggyShoes]

Everyone: Thank you all for the responses! This site is awesome.
I do want solar and on a 34 foot class-A, I should be able to get some up there. Fully equipping the RV with solar is going to have to come in stages. How much solar I can put up right away depends on the cost of the main system.

Also, I added the Victron Smart BP-65 (battery protect) going to my 12v fuse boxes. If my lithium battery is low they shutdown before the Bms turns off. That way loads cannot drive my lithium to bms low voltage shutdown. I would use that instead of the on/off switch between the Distributor and the 24-12v converter. It can also act as a on/off switch too. (I have used it more to reset the power to my furnace than anything else).

You probably do not need on/off switches between the mppt and the distributor- you have a fuse at the distributor and via the app you can turn the mppt off. You will want a on/off switch (or breaker between the solar panels and the mppt, that way you can turn the sun off for maintenance and testing.

@Rocketman,
Thanks for the catch on the extra wires from the inverters. I wont be using the L2 out.

I switched the on/off switch going to the 12V load to be the Smart BP-65 like you suggested.

I also changed the on/off switches on the solar to be between the panels and the MPPT. I also changed the on/off switches on the solar to be breakers or fuses and an on/off switch.

I will definitely do the AC easy starts if they are not already on there (I haven't checked).

 

[justinm001]

Everyone: Thank you all for the responses! This site is awesome.
I do want solar and on a 34 foot class-A, I should be able to get some up there. Fully equipping the RV with solar is going to have to come in stages. How much solar I can put up right away depends on the cost of the main system.




@Rocketman,
Thanks for the catch on the extra wires from the inverters. I wont be using the L2 out.

I switched the on/off switch going to the 12V load to be the Smart BP-65 like you suggested.

I also changed the on/off switches on the solar to be between the panels and the MPPT. I also changed the on/off switches on the solar to be breakers or fuses and an on/off switch.

I will definitely do the AC easy starts if they are not already on there (I haven't checked).

The lynx distribution has spots for fuses so anything going to there doesn't really need anything.

Solar panels are realitively cheap 3000w is like $3000. It's the mounting and mppts that are about the same price. And at 24x it's twice the price for mppts as 48v. Drilling holes in the roof and mounting solar is the hardest part in this setup. I'd suggest getting that done in 1 stage even if not connected or overpanneled.

 

[sunshine_eggo]

48V 50amp hybrid RV system

So what happens when you forget or someone else plugs into a different source. I don’t need the worry, yes the 120x2 is easy, nothing to change or worry about. Glad what you have works for you. Huh, there's nothing to forget it operates the exact same as the 2x120. The switch as group option...

diysolarforum.com

Resuming from the above.

Quattros should be avoided unless you absolutely, positively need two separate AC inputs that can't be accomplished with an ATS OR you can't find a multiplus in the configuration you need.

Most 50A RVs already have an ATS to select between on-board generator or shore.

I don't see how the Multiplus would not accommodate your gen auto-start.

Disadvantages of the 2x120V units:
1) you can't charge from the second leg of 50A shore power. It is only pass through to the L2 side of the AC panel.
2) You are limited to an absolute 6000W inverter output due to the fact that you're on one leg, and N will always carry max current.

Advantages:
1) comparatively simple handling of switching between 30A/50A shore power.

Disadvantage of 2X standard 120V units in split phase:
1) Requires a specific setting when placing them in parallel, "Switch as group" disabled.
2) Use of a custom 30 to 50A adapter that only passes through L to L1 is preferred. Otherwise, connecting through standard 30A shore will cause random inverter to sync to shore.
3) On 30A shore, can only charge with one

Advantage of 2X standard 120V units working in parallel for 120/240VAC split phase.
1) You can charge from both legs if 50A shore is provided, and you pass through the full 50A to each leg.
2) more variety (48V & higher power units)
3) potentially lower cost or better value.

$2933 for 6kVA in 2X MP-II/Q-II 24V 2x120 units ($0.49/W)
$3944 for 10kVA 2X MP-II 48V 120V units ($0.39/W)

 

[justinm001]

48V 50amp hybrid RV system

So what happens when you forget or someone else plugs into a different source. I don’t need the worry, yes the 120x2 is easy, nothing to change or worry about. Glad what you have works for you. Huh, there's nothing to forget it operates the exact same as the 2x120. The switch as group option...

diysolarforum.com

Resuming from the above.

Quattros should be avoided unless you absolutely, positively need two separate AC inputs that can't be accomplished with an ATS OR you can't find a multiplus in the configuration you need.

Most 50A RVs already have an ATS to select between on-board generator or shore.

I'd much rather have Victron manage the auto transfer with the Quattro. Also I'm able to see if power is coming from shore vs genset and log.

The 5000w ones and up can transfer 100a on each input and output so when high loads on 50a shore you're able to power assist above 50a on one output.

I think the biggest perk is you're able to set separate input limits. The MP can use the gen autostart but you have to make sure input limit is set right. OP has 5kw genset so would need to drop it from 50a each time.

Plus all the assistants and everything.

 

[SoggyShoes]

Quattros should be avoided unless you absolutely, positively need two separate AC inputs that can't be accomplished with an ATS OR you can't find a multiplus in the configuration you need.

Most 50A RVs already have an ATS to select between on-board generator or shore.

Okay, now I am getting confused... or more confused. I see that there is agreement that using two 2x120V inverters is not the way to go. But, @sunshine_eggo, why should I avoid the Quattro so much? Isn't their entire purpose over the Multiplus to seamlessly incorporate a generator into the system by having an internal automatic transfer switch? Please clarify.

By the way, my RV does not have a automatic transfer switch. Currently, I literally have to plug the 50amp plug (NEMA 14-50P) into the generator socket in the basement compartment. It wouldn't be hard to install a transfer switch. I was just thinking it would be nice to have it all seamless.

 

[justinm001]

Okay, now I am getting confused... or more confused. I see that there is agreement that using two 2x120V inverters is not the way to go. But, @sunshine_eggo, why should I avoid the Quattro so much? Isn't their entire purpose over the Multiplus to seamlessly incorporate a generator into the system by having an internal automatic transfer switch? Please clarify.

By the way, my RV does not have a automatic transfer switch. Currently, I literally have to plug the 50amp plug (NEMA 14-50P) into the generator socket in the basement compartment. It wouldn't be hard to install a transfer switch. I was just thinking it would be nice to have it all seamless.

The Quattro just costs more and has an auto transfer switch. It's a better but more expensive unit. The point @sunshine_eggo is making is that there's usually not much of a point in removing an auto transfer switch from an RV to put in a Quattro.. Purely because of money. I removed my ATS because the Quattro is much better. Also it's seamless and no loss in power.

 

[SoggyShoes]

So if the Victron 2x120V are out, then what should I go with?

I am also wondering if other than some newer circuitry and more efficient, does the Quattro II or Multiplus II have any real advantage for mobile applications? From what I can tell it seems the advantages are mostly for permanent connections to the grid in some countries. Is the increased efficiency in the version II that much more than the originals? I am asking because, besides being curious, it seems like the form factors of the original Multiplus and Quattro would be a lot easier to fit in a basement compartment of the RV.

After all your input I have these two diagrams....

 

[justinm001]

So if the Victron 2x120V are out, then what should I go with?

I am also wondering if other than some newer circuitry and more efficient, does the Quattro II or Multiplus II have any real advantage for mobile applications? From what I can tell it seems the advantages are mostly for permanent connections to the grid in some countries. Is the increased efficiency in the version II that much more than the originals? I am asking because, besides being curious, it seems like the form factors of the original Multiplus and Quattro would be a lot easier to fit in a basement compartment of the RV.

After all your input I have these two diagrams....

I don't thing the 2s are better than the 1s. They're just a different form factor and flatter and just a bit different specs. Idk if more efficient or anything. I wouldn't say the 2s are the new version of the 1s.

Typically the 2s would be better in most basements because they can go along the wall and not pop out as much. My 5000s are like squares

If the Quattro 1s fit your space just we we'll or better why not get that.

 

[Rocketman]

With a RV - space is ALWAYS something to consider- make sure you can physically fit everything- before you buy it. Two big inverters and four batteries will take up a lot of room.

 

[paul65k]

So I agree that there is little need for the Quattros or the MPIIs 2/120. We do installs like this with dual MP (ones) for split-phase as there really is no benefit to using twos unless the space equation works, and even then just get the standard 3000W MPIIs, not the 2X120s as this is not needed.

The only good reason I can see for the Quattros is to get 5000W in a 24V configuration as the only MPIIs available at 5000VA (4000W)….. but paying a good deal more for the switching you will likely not use.

 

[SoggyShoes]

So I agree that there is little need for the Quattros or the MPIIs 2/120. We do installs like this with dual MP (ones) for split-phase as there really is no benefit to using twos unless the space equation works, and even then just get the standard 3000W MPIIs, not the 2X120s as this is not needed.

The only good reason I can see for the Quattros is to get 5000W in a 24V configuration as the only MPIIs available at 5000VA (4000W)….. but paying a good deal more for the switching you will likely not use.

Thanks @paul65k
I am going with two of the Multiplus 1 24v 3000W. I think that will be plenty to run both A/C units (one on each inverter). The Multiplus are shorter so that can sit upright in one of my garage bays.

The Quattro would be awesome for more power and to have that generator permanently attached but it is a lot of money for what essentially is an automatic transfer switch for me.

I am really excited to get going on this project!