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multiple inverters

50a 5th wheel with dual Multiplus configuration help

Hello all-

I am a new member to the forum and was directed here by a friend who suggested this community may be able to help with sorting out some diagnostics and setup issues I am having with my DUAL Victron Multiplus 12/3000/50 120v installation.

My system was installed a year ago by a licensed electrician familiar with solar and larger off grid systems, but who had never worked with RV's or Victron equipment & the mix of (relatively) small-scale 12V DC and 120V AC. As such, the initial configuration and details of Parallel vs Split-Phase wiring and setup were never fully understood by or explained to me, and within a short time issues started to appear. After learning some basics myself, it appears that my system was wired to be used as a split-phase setup (see PDF single line drawing attached as provided to me by the installer), but the two Multiplus inverters were never connected via an RJ45/Ethernet communication cable, and so have basically been operating as two separate standalone units, each serving one side of my RV's AC breaker panel. As I have learned, this will lead to some issues since the Neutral wire is shared between the units, but they have no way of knowing what the other unit is doing.

The two problems I have been experiencing are:

1) The biggest issue is this: When connected to a 240v 50a shore power receptacle, if I set the input AC current on either inverter to MORE than 20a, I start running into major issues when any significant load is applied (Air Con, Electric FP, etc) - the inverter will give me overload errors, will bounce between Pass-Thru, Assisting, Inverting modes, and will sometimes actually show a NEGATIVE AC input, as though it is trying to back-feed the grid, though have never actually put a clamp meter to this to verify if it is actually happening. If I keep the shore input to 20a or less on each inverter, they operate flawlessly regardless of shore power connection type (or when strictly off-grid/inverting), which is basically what I have been doing for the last year as we live & travel full-time in our RV.

2) Secondary, and less important issue is that I pop the GFI on any 120v 15a or 20a GFI-protected receptacle within 5-10 seconds of connecting to it, if that happens to be my shore power connection.

After doing much reading on this forum and elsewhere, I think what I need to do is simply disconnect from shore power, connect my Multiplus' together (via RJ45/Ethernet), and connect one of them to my laptop via RJ45/Ethernet cable and program them in Split-Phase through the VictronConnect app (I have a Victron USB MK3 Dongle). But before I do this, I wanted to reach out to all of you to see if there is anything else in my setup that is of concern, or that would prevent me from doing this. Again, please see the attached PDF single line drawing that includes my hardware details.

If I go this route (Program to Split-Phase), it is my understanding that when on a 240v 50a shore connection, the Multiplus' will each pass through 50a to one side of my AC breaker panel, and that everything will work as expected with ample power available. When connected to a 120v 30a (or 20a or 15a) shore connection, one inverter will pass through that amount (or use to charge batteries), plus the "Assist" wattage will also be available from that inverter. The second inverter will reject the incoming shore power (since it is the same phase) and will operate in Inverter mode only, up to its maximum inverter wattage. Do I understand this correctly?

The other option I have considered is to go the parallel route, but it is my understanding that some re-wiring would need to be done to facilitate this, and that I would always be limited to the maximum amperage of one leg of any shore connection (ie 50a total on a 240v 50a shore connection). Is this correct?

Greatly appreciate any advice or feedback you can offer - thank you!


Details on hardware & wiring:

AC Wiring To/From Shore/Inverters/AC Panel: 6/2 & 6/3
DC Wiring: 4/0 To/From/Between Batteries, 4/0 To Multiplus' from Lynx Distributor

6 - Battle Born 12V 100Ah
2 - Multiplus 12/3000/120-50 120v VE Bus
1 - Victron Lynx Distributor
1 - Victron BMV-712 Battery Monitor
2 - Microair EasyStart 364 (One on each Air Conditioner)
2 - VE.Bus Smart dongle
1 - Victron SmartSolar MPPT 150/85
1 - Battery Guard AutoSelect
6 - Canadian Solar 305w solar panels

Solar & Battery Wiring Line Drawing.pdf

rv-solar asked
snoobler commented ·

1 Answer

Physical button control of MultiPlus with CerboGX

I have an existing MultiPlus 12/3000/120 inverter that i am thinking of adding a CerboGX to gain some additional functionality. According to the manual for the CerboGX, the inverter may only be controlled by the CerboGX and may not be controlled by a physical switch. I currently have a physical switch wired to the MultiPlus (terminal H in the MultiPlus manual) and wish to keep the functionality a physical switch provides. The CerboGX manual makes it seems this is possible using something called an “Assistant“, specifically the safety shut off assistant. There isnt any info in the CerboGX manual about using an “assistant“ from I can tell. It seems that my objective should be possible by wiring my physical switch to a GPIO/contact closure on the CerboGX and programming the functionality in the Cerbo but how to accomplish that isn’t abundantly clear. If anyone can fill in the blanks for me, i would be greatly appreciative!

mrcrowley11 asked
mrcrowley11 answered ·

2 Answers

Victron (transformer based) Inverters: continuous discharge current from batteries question


One of my local retailers has this following statement regarding Pylontech batteries:

"Transformer based inverters or Victron inverters specifically specify a 100% continuous discharge current from the batteries. As an example for the 5kVA Victron which is 4kW the battery requirement would be 4000W / 48V = 83A continuous discharge current from the batteries. In this case a full 3 x US3000 or 4x US2000 batteries would be required."

Could someone please show me where exactly on the datasheets of Victron Inverters, or in their manuals, this little nugget of information is. I'm at a loss. Is it even right?

rattus asked
rattus answered ·

3 Answers

Two inverters in 12v van system / paralleling batteries

Hi all, I have a 12v 600ah lifepo4 setup in my van, ~300 amp max discharge. Not Victron batteries, but all other components are. My main inverter is a Multiplus 3000. I am planning to add a Phoenix 500 watt inverter to use for small loads, mainly laptop charging, so that I do not have to always fire up the Multi. I plan on running them both to my Lynx Distributor separately and fusing them appropriately. The Multi will power my AC breaker panel, the Phoenix will just run one plug via the outlet on the unit. I do not plan on running them in tandem, but it may occasionally happen unintentionally.

Does this all sound good/acceptable? I believe it should be fine, but I'd like to tap into all the knowledge of this community.

Another question that maybe should be its own post, but my bank is two 300ah batteries. They will be paralleled, but I am going to fuse them separately and have a Blue Sea switch for each individual battery. From there they will go to the Lynx distributor. I am contemplating whether they should be paralleled at the distributor, or beforehand, which would allow me to also have a master switch, in addition to the two individual battery switches. Redundant, I know, but still thinking about doing it.

What are your opinions? Each to its own position on the Lynx, or paralleled beforehand and share a position on the Lynx? I know I can just parallel at the battery, but I prefer to fuse and switch each individually and parallel downstream. If paralleled before the Lynx, suggestions on what busbar would be best suited for that? This may be stupid, but could I just run each battery cable (after fuse and switch) to the same post on an appropriately rated master switch, then to the Lynx?

Thanks much for any and all opinions/suggestions.

igvan asked
shaneyake commented ·

7 Answers

Multiplus with CCGX keeps dropping my PV inverter connected to EM24

This has seemed to happen since the last update. I have reset the solar with the isolator a few times. and at the circuit breaker before the em24 but its constantly dropping off any ideas guys?

This is the old EM24 din not he ethernet one. it has the rs485.

Dale asked
Dale answered ·

3 Answers

Should I use a larger inverter, or smaller dedicated ones?

I have a motorhome - i am contemplating, should I have a dedicated say 300W inverted for my fridge (my only 24/7 load) or should I not worry and just have one larger inverter. what are the losses when the load is only say 40W - thanks

luderick asked
Kevin Windrem answered ·

4 Answers

Accidentally damaged the LEDs on MultiPlus, what now?

Hi all. I am at a loss right now. I am in the process of setting up my vans victron system, and today noticed that I somehow broke the “mains on” and “bulk” led lights on the multiplus. The cover was off, and they were somehow bent to the side with the top solder on each being snapped off. I am feeling sick that I let this happen. Unbelievably careless. So now I am wondering how I can get this fixed, and more importantly, what other damage I may have done to the inverter. Can I still use it assuming the only thing I hurt was the led lights? Will the broken solders cause any additional damage if the unit is powered on? Man, I’ve made mistakes, but this one really, really hurts. I am at a complete loss. Thanks in advance for any advice and help.

igvan asked
igvan commented ·

7 Answers

Can you add more Multiplus inverters (of the same type) to an off grid system when it is expanded at a later date ?

Having set up an off grid solar system with two 3000VA Multiplus Inverters, is it possible to add another inverter (of the same type) years later when the system is expanded with more solar panels?

Does it matter if the identical inverters are of different ages / editions? I.e. pairing a 2022 model with a 2025 (for example)?

Many thanks!

hobbes asked
nickdb commented ·

1 Answer

Multiplus II and Pheonix invertor Ve.Direct on same Battery bank with seperate AC.

Is it possible for me to add a pheonix invertor VE.Direct 48/375 to my existing battery bank which already supplies my Multiplus II.

I would keep the AC output of the 48/375 seperate as I just need a small invertor for a dedicated AC circuit.

Would CPC/earth of the Multiplus II and 48/375 cause a problem if they have seperate AC out circuits but grounded to negative on the same battery bank? This is the only thing I can think of that would stop me having this setup as the earth and grounding is quite a complex consideration under a DC/AC fault condition.

Is this possible?


johnsmith asked
shaneyake answered ·

1 Answer

Multiplus II feeding Easy solar II via shore/genny input

multiplus II (24 3000) with nife batteries (epever charge controllers) connected to easysolar II (48 3000 with pylon2000) via shore/generator input. This setup works but i want to limit the easysolar input current based on the battery voltage of the multiplus (using the aux input and an assistant on the easycurrent). Happy to get into the weeds on the how and why but my question IS - is the aux input protected? - ie is there any chance of a runaway feedback loop if i direct feed battery voltage (probably just one cell) from the same device (multiplus II) that provides an input (via the shore/generator input). Thanks in advance, Alex.

knownot asked
knownot answered ·

1 Answer

Multiplus2 GX startup


We have just installed our MP2 GX inverter. Switching on we get the Victron welcome. Then Status Invert then ACdisconnected +6w. The AC1 is connected via a sub board with CB to a power outlet. Is there something we have not done to get the AC flowing.

Thanks in advance

llowalong-farm asked
knownot answered ·

2 Answers

Zusätzlicher Wechselrichter am Multiplus II GX

Ich möchte meine Anlage erweitern.
Dazu möchte ich einen Wechselrichter (ohne Batterie) zum einspeisen nutzen.
Welche WR können mit dem Multiplus II über LAN miteinander kommunizieren, so das ich wieder die Nulleinspeisung sicher stellen kann.
Gibt es dazu irgendwo eine Kompatibilitätsliste?


PS. kann mir mal jemand sagen, was ich im Forum bei Thema eingeben soll? das passt bei mir nie.

rodenberger asked
rodenberger answered ·

2 Answers

Multiplus II GX ESS + micro inverters + battery + SE inverter


I have a question about how to best connect two separate PV setups to the multiplus II gx. One of the PV setups is a solaredge3680 system which should not be a problem since the MP can connect to it through the ethernet network. I'm going to connect these through a 16A fuse.

The other setup consist of multiple micro inverters from APS systems DS3 880 inverters. The total of these should fit on a 16A fuse as well.

Since I read in other topics that the micro inverters are difficult to manage from the MP system and that these are best put on the AC IN port of the MP so the MP can shut them off entirely if the grid fails and too much solar power is generated by the setup.


I'm also considering to replace one (or more) of the micro inverters by a MPPT 48V inverter directly connected to the battery link. This in case the battery runs completely empty and I need direct 48V charge to restart the entire system.

My questions:

1) Am I correct that the output of the MP II GX will never exceed the 4000W in this setup? So am I safe in using a 3x 2.5mm2 cable (25Amp max) and using a 20A fuse?

2) Is there an alternative for the ET112 to use that uses ethernet or someting? How stable is a zigbee connection between the ET112 and MP? Distance is about 60 meters including through two outside walls.

3) Is it overkill to install a (small) MPPT inverter to be able to recover the battery in case of depletion? (Perhaps it is .. I do have a small generator at hand as well).

4) Is the setup as depicted in the drawing safe with regards to fuse and cable usage?

5) Is there anything I'm missing?



robsimons asked
robsimons answered ·

1 Answer

Multiplus 12v/3k restarts every 30 secs with VE.Bus BT dongle plugged in
I have a new one I haven't ran into before. A Victron Multiplus 3k in inverter mode with a smart VE.bus BT dongle plugged in causes the inverter itself to restart every 30 seconds. The inverter is just on, with no loads and green inverter light is on saying everything is fine. Every 30 seconds the invertere restarts by itself There is no shore power, it's just inverting. There are 3 Battle Born batteries the inverter is hooked to and the battery voltage is fine since there is no load or anything.
If you unplug the VE.Bus BT dongle the rebooting stops. I can hook up to the MK3 to the inverter/laptop using the exact same cable and everything is fine. The culprit appears to be the VE.Bus BT dongle, but I've never seen this before?

- Victron Multiplus MP1 12v/3000 with latest firmware
- Victron VE.Bus BT dongle with latest firmware
I swapped out the network cable (both are from Victron)
I tried both RJ45 ports on the Inverter
Restarted both devices
As long as the VE.Bus BT dongle is plugged in, the inverter reboots every 30 seconds. If you unplug the dongle, everything is fine.

bluelghtning asked
william-wright answered ·

2 Answers

Multiplus switching to inverting without loss of grid

We have 3 Victron Multiplus 5000's that are in 3-phase. The system powers an AV rack room on our vessel. Our mains supply is from generators. What we see happening is the output current drops even though the grid power is available. The multiplus' go into inverter mode for a brief second. Then to bulk. Then shut off and automatically comes back on.


Anyone have an idea why the multiplus goes into inverter mode with grid power present?

eminence-eto asked

0 Answers

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