I would appreciate help reviewing my wiring diagram for a sailboat

DIY
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Victron Wiring Diagram – Lagoon
Victron Wiring Diagram – Lagoon1920×1495 231 KB

Hi,
I’m looking for some help reviewing a wiring diagram I’ve created.

If anyone has time to check not only the wiring but also suggest alternative products or improvements I may have overlooked, I would really appreciate it.

This is my second larger system using Victron products. The first time, I built a system for a motorhome. With help from this community, My family and I lived in that motorhome without any power issues for 18 months.

Now it’s time again, but this time it’s for a boat. The system is designed for our Lagoon 380 sailing catamaran, which we plan to live aboard long-term.

I haven’t bought the components yet, so most things can still be adjusted based on feedback. However, a few components are already installed in the boat, which has influenced some of my choices.

One MultiPlus II 2000VA is already installed. Since the gas has been removed and we plan to use an induction cooktop, I’d like to increase capacity by running two MultiPlus II units in parallel for a total of 4000VA.
I’m a bit unsure here: I’d also like to make use of the combined charging capacity (80A + 80A). Can I connect the units as shown in the diagram? Is this a valid setup for paralleling two MultiPlus II inverters?
Will the GX Touch 50 support monitoring both inverters?

I’ve chosen to include an isolation transformer, as we plan to spend some winters in Mediterranean marinas, and I understand it may be a good safety investment. I’m assuming many marinas limit shore power to around 2000W – which influenced my choice. A larger transformer seems like unnecessary weight unless really needed. If anyone has experience with this, I’d appreciate your input.

The larger MPPT is already in the boat and connected to an existing solar array. We plan to add two walkable solar panels, and my thinking was to connect those to a separate MPPT, hence the two different charge controllers.

I’ll check the amperage of my alternators and might go for the Orion TR-12/12-50A instead.

We’re also planning to bring a portable generator. I currently have a 1000W unit but would consider upgrading to 2000W if needed. I plan to connect it to the shore power inlet.

I haven’t fully calculated the DC system’s total current draw yet, but since we’ll be running two anchor winches and a 12V watermaker, I’ve planned for two BatteryProtect 220A units.

Any suggestions are welcome, especially if I’ve misunderstood something in the wiring.

Eventually, I’d also like to connect tank sensors for two diesel tanks, two holding tanks, and one freshwater tank. I assume I’ll need a GX Tank 140 for this?
How many tank sensors does the Cerbo GX support?

I’ve also read that it’s possible to integrate this with Raymarine equipment. I’d appreciate any guidance on how to do this and what port/interface is used.

Thanks in advance for your help!

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  1. You show a Lynx Power in for the batteries. How are you fusing these. Mega fuses have too low interrupt current and are not suitable. You could use separate Class T, the Lynx Class T or a Lynx Distributor with Adler EF3 fuses as in this post EF3 fuses in Lynx Distributor.
  2. You show resettable breakers, make sure that these are from reputable manufacturer such as BlueSea.
  3. There is a lot of info on parallel Multiplus systems here, VE Bus parallel. See limits on model / firmware for parallel set up. Set up properly in parallel the Cerbo sees them as one system.
  4. I would have thought 16A shore power is also common so a 3600W isolation transformer, would be useful, but agree not a necessity.
  5. I recommend using the Orion XS or Orion 1400 DC to DC converters. These are newer products and connect to the Cerbo GX and charging can be fully controlled by the BMS unlike the older Orions. The newer Orions also have programmable charge current so you could reduce to say 40A if your alternators were running hot at 50A. The newer Orions are non-isolated so your starter and house batteries would need to share a common negative.
  6. The Cerbo can connect 4 resistive tank senders directly. The GX Tank 140 can connect 4 tank senders, either voltage or 4-20mA. You need to choose senders to match.
  7. Read the Cerbo manual about connecting to NMEA2000 etc.
  8. I have not checked your wiring in detail, it looks OK on a quick look.
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Hi, thanks for the replies you’ve given me a lot to think about.

  1. I’ll read up more on the Lynx Distributor and see if I might make some changes there.
  2. The plan is to go with Blue Sea for the fuses shown.
  3. I’ll also look more into parallel connections. The inverter I have is from around 2017, so I need to find out if I can still buy the same model today. Otherwise, I might have to replace both and go with a single 5000VA inverter instead.
  4. I’m leaning toward thinking it’s a lot of extra weight to carry around just for the few occasions when I might be able to draw up to a 16A shore power supply. Not quite sure yet – I’ll think about it.
  5. I’ll read more about this, but I thought it was possible to set the charge current even on an Orion-Tr unit?
  6. I’ll probably leave the tank sensors for now. I’ll check what’s already installed in the boat and adapt based on that.
  7. Thanks, I’ll do that.
  8. Thanks I’ll post an updated diagram once I’ve done some reading and made a few changes.
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  1. As far as I know, charge current is fixed in the older Tr units. You can download the VictronConnect phone app and run that in demo mode and chose most Victron products and look at the settings availablr, no charge current setting for the Orions in the demo mode. Check in the manual.
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Blank diagram - Victron Lagoon
Blank diagram - Victron Lagoon1920×1446 207 KB

Hi,
I’ve made some updates to my previous wiring diagram based on the feedback I received. After some consideration, I also decided to go with a larger inverter. I did some reading on the Orion XS and it clearly seems like a better choice.

Would someone be able to review my updated wiring diagram and let me know if I’ve missed anything? A few communication cables are still missing, and in some places I haven’t specified the cable dimensions yet, as I don’t know the exact distances.

I’d really appreciate any feedback.

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  1. Are the batteries you are planning the new NG series ? if not - i would go that way

  2. I would add a bypass switch between the isolation and the Multiplus - so in case of failure you can power the boat via shore power direct.

  3. I would probably recommend NMEA 2000 tank monitors if you have > 4 directly connected to the Cerbo. WEMA makes rather cheap “converters” for standard tank senders. Much cheaper than the GX140 and more versatile.

  4. Consider adding Zeus Arco’s or Wakespeed controllers to your Alternator charging - both interface with Victron direct.

  5. You are skating on the limit with many marine induction stoves / ovens and 5000VA/4000W inverter - especially if it gets hot where inverter is installed. But if shore power connected Victron’s power assist will keep your belly full.

  6. If you did not use induction oven - I would probably have recommended a charger based approach with “stand-alone” inverter (That is the Nigel Calder favourite solution) - as chargers accept wide range of power inputs - so for blue water cruising you can go anywhere without issues - and it keeps galvanic isolation problems very small. Sadly Victron’s Isolation Transformers are not great at accepting wide voltage ranges. If incoming voltage is too high or too low it will bark at you and not work. The problem is Isolation transformers in general RAISE the voltage “internally” a little bit - but in modern marina’s that can become an issue in low consumption times of day. Input voltage goes quite high - meaning output to your boat get’s above the absolute limit the inverter will accept.

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  1. You will need 2 Class T Power In units, they only do 2 batteries per unit.
  2. I agree with @kaz911 on the NG batteries and consideration of Wakespeed WS500 for alternator charging rather than Orion XS, I am using both successfully. More expensive and but better for charging control and looking after the alternators.
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Hi,
Thanks for the feedback!

  1. Yes, the plan is to use the new NG batteries.
  2. I’ll take a closer look and consider implementing that kind of solution.
  3. Thanks for the tip – I’ll wait and think a bit more about how to handle that, but it’ll likely come after this installation is complete.
  4. I’m leaning towards using the Orion XS. My alternators only deliver 80A each, so I’m not even sure I’d dare pull 50A of charging current from them. I might reconsider if I switch to high-output alternators. But what would you say is the biggest advantage of using Zeus Arco’s?We’ll only have two induction cooktops that together draw around 3500W at maximum power. The oven is a small unit and only pulls 800W, so I believe this inverter should be sufficient, even in warmer climates. And if not, we’ll just need to be cautious not to run both cooktops at full power simultaneously.
  5. Thanks for that additional note. I don’t think we’ll use the Power Assist feature very often, but I will probably connect a few outlets to the AC Out 2 port. If we’re docked during the winter, it’s nice to know that potential heating devices will shut off if the shore power trips.

Interesting point about voltage fluctuations – now that you mention it, I’ve actually experienced that quite a few times in our motorhome.

One follow-up question:
I already have a 40A charger installed on the boat that I plan to remove. But couldn’t I, after the isolation transformer, install a transfer switch or a simple manual bypass switch, and then completely isolate shore power from the inverter and instead run it through the charger?
I don’t expect to use it often, but it could be a way to still get 40A of charging when needed.

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Thanks, I’ll go for two :slight_smile:

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With 80A alternators you would want very max 50A continuous current. You will have to manually check the alternator temperature and manually adjust the Orion current.

Advantages of the WS500 / Arco Zeus

  1. Has a temperature probe on the alternator so current limiting is automatic.
  2. Has a feature to dial back alternator power output at low rpm, this may not be much use to you. For me with a 40hp engine and. 12V 175A alternator that is geared to give 175A at tickover the engine would struggle in gear at low revs, with the WS500 it now delivers 50A at tickover rising to full power at 1300rpm.
  3. More efficient, although the Orion XS is better than the older versions.
  4. On an engine with twin alternators, engine and house (as mine), using the Orion needs the buffer battery, with the WS500 you can charge lithium direct.
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Yes that would be a great idea - and give you best of both worlds - but I would have the transfer switch before the isolation transformer as long as it is ONLY connected to your battery. A DC charger is by default an isolation transformer in itself as feed-in Live and Neutral are not “touching” your DC side. You could even just have the charger on a separate cable / plug going into the boat.

For the Arco Zeus (at least) and maybe on the WS500 - it gives you the option of turning on your engines - and switch Zeus to “generator mode” where they will load your engines to generate as much power as possible - even in “neutral” - I think @pwfarnell has covered the other benefits.