Please review my wiring diagram

Jan 16, 2022
Hello, looking for peer review and critique for my proposed wiring schematic on my 45ft glass fiber sailboat. This is edition 1 so I expect there to be some faults.

This was drawn using with the addition of a Victron products html file and many copy pasted images off the web. Very simple but very time consuming. There is a great video on you tube about the basic operation of (search REC BMS diagram net demo)

Following are some initial questions I have:

  • Starter circuit – grounded to engine – no other return to starter or alternator. How it was (is) setup by marine electrician. Normal? Problematic?
  • is the engine block my ground for all systems (starter/12v/24v/220v) ... should I be setting up a grounding plate/bus? As opposed to running the 2x50mm cables direct to engine block.
  • Grounding in general – this topic seems widely accepted as extremely confusing… I agree… what corrections need to made to my proposed grounding.
  • 2x Orion tr smarts isolated for starter -> house charging - the units I have are the isolated versions. The starter batteries are grounded to the engine block. I assume they will still function perfectly well, im just curious about what this does the ísolation of the units
  • 2x Orion tr smarts isolated for starter -> house charging - 30 amp mrbf fuses at the battery post as per recommended in manual… minimum fuse available for lynx distributor is 40 amps…problem?
Worth noting:

  • I understand that the dual 17A Orion TR´s will draw 75% of the capacity of the 45amp alternator. In the future I hope to upgrade the current alternator. For the mean time I will monitor closely the temperature with a flir camera and act accordingly. (wondering if it is possible to derate the orions on the app?)
  • No cerbo gx at this stage. May use a raspberry pie in the future with Venus software. For now im happy monitoring via apps/mk3 adapter.
Thank you very much in advance,



  • 300%little wing wiring diagram 30-1.drawio.png
    300%little wing wiring diagram 30-1.drawio.png
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The only mistake I found was your bmv712 monitoring the starter battery is on a 12v post - not the 24v post.

You may want to add a small switch on one or both of the Orion 24-24 - loop on/off switch. That way you can shut one down when on idle or the alternator gets too hot.

Multiplus- you will need some way to “control” the Multiplus- change the input 220v amps (unless they don’t change from dock to dock). For that control you have (at least 3 options)

1. VE.Bus smart dongle- this puts the signal Bluetooth onto your phone.
2. DMC - Digital Multi Control-
3. GX device - Cerbo(many others too).

I would not get the DMC - use the money to get the one of the others instead. The smart dongle may make the most most sense for you - but I really like my CCGX (older GX -like the Cerbo & Touch)

Very Good drawings - I did not look at wire sizes very well - because I don’t know the equivalent sizes from awg to mm.

Good Luck with your project.
Hi Rocketman, Thanks very much for taking the time to look it over. good catch on the bmv wire. have now changed that in the schematic.
Im new to the Orions. Was planning to keep a close eye on how much heat they draw out of my alternator with a flir camera at different rpms and idle to get a feel for when to intervene. my intention was to disable/engage them with the app initially. but thanks for the advice, i very well may install a switch after ive gotten past babying them. I have the mk3 adapter for the multi. im very seldom attached to shore power but so far most dock stations have been quite reliable, and as far as i understand it the multi will accept 180-265V. does it not adjust this automatically?
The control of the Multiplus is to switch between
Charger only
Inverter only
And to adjust the incoming amps.

In my 120v - my incoming amps can be:

With yours maybe you will not need to adjust the incoming amps - set it and forget it. (You adjust amps not volts).