I am upgrading an electrical canal boat from a BoOEI (Bunch of Old Electrical Installations) to a single NIVI (Neatly Integrated Victron Installation).
To accomplice that I will be installing a single Cerbo GX to monitor (and control via Node-RED where required) both the propulsion motor and battery system, as well as the house battery and AC loads (in/out) system.
The propulsion battery is the primary battery and has an integrated shore power charge system. Itās characteristic parameter values shall be displayed on the boat page of a dedicated GUI v2 display (SoC% and time-to-go). The DC propulsion motor is the only load and its DC power values are measured directly and shall also be displayed on the boat page. Drive speed is provided by GPS and additional motor parameters are provided through Sevcon GEN4 CANopen integration.
The boat has a secondary house battery with a MultiPlus II 5000 for charging and is dedicated to supply AC house loads while sailing.
Strictly speaking there is a third 12V battery system that I will put aside for now. That battery supplies the regular 12V DC boat loads (navigation lights, radio comms and bilge pumps foremost) and is charged by a stand-alone Victron charger plugged into a secondary AC-out(2) socket of the MultiPlus II. This will prevent unnecessary permanent charging while sailing. In case of an emergency / failed 12V battery, this charger can be plugged into a primary AC-out(1) socket.
The whole system shall be monitored by the Cerbo GX and shall have itās live data feed be made available in a single VRM instance through a dedicated permanent mobile internet connection.
I believe all this should be feasible without much complications but I have some areas of doubt because we need the Cerbo GX, VRM and the GUI v2 display set-up to monitor the primary DC system. For the secondary DC/AC system with the MultiPlus II we only need basic monitoring capabilities through VRM and not necessarily on the display.
In summary:
A primary propulsion system with:
Primary propulsion battery with BMV-712 Smartshunt as Battery Monitor.
Sevcon GEN4 controlled motor with Smartshunt as DC Motor.
Dedicated 3-phase charger with an EM540 AC power meter.
No need for 3rd Smartshunt as the DC charge current plus the DC battery current plus the DC motor current always equals to zero.
If needed the 3rd current monitor can be setup as virtual current monitor in Node-RED.
Alternatively the 2nd Smartshunt could also be wired and set up as DC Charger or as DC system, please advice what is best practice here.
A secondary house system with:
Secondary house battery with BMV-712 Smartshunt (Battery monitor)
Multiplus II 5000 (ve-bus connected to the Cerbo GX)
I wonder whether the use of virtual devices can be avoided completely in this setup. Or if not, what virtual devices and other measures are required to make this work as a Neatly Integrated Victron Installation.
Please advice on best practices for the requirements stated.
I think that you are going to have some issues here. The Multiplus is the heart of the system and connected to the GX will assume the central role in the screen. However, if you are setting the drive battery as the main monitored battery bank then that will not align with the Multiplus, which is assumed to be powered by the āmain batteryā. Electric boats that I know of have a single 48V lithium battery supplying both the motor drive, dc loads and the Multiplus for house ac loads. This arrangement then sits well with the default Victron monitoring setup. I have no idea how you are going to separate out your functions to avoid the GX getting things wrong.
From your description above, it seems that the propulsion system is completely independent of the house and navigation systems. As such, it should have its own independent monitoring and control, with the data from the house system displayed on that as a subsystem.
For the 12V nav system battery, this is best float charged via a dc/dc converter, this is more efficient than using the ac charger from the inverter driven by the house bank. Whilst this can be left on float charge indefinitely, you can also add a switch or relay to control when the charging should function.
The 12V gets charged by shore power dayly, Iāve only ever encountered a situation where there was a need to charge it off shore when either the battery was EOL or someone forgot to plug the charger in. But yes, for long haul off shore isolated dc-dc is the way to go. Or when the 12V would power a bow thruster.
I am not making any assumptions that the current installation on that boat has been sufficiently thought through on the subject of correct grounding (nor any other electrical subject for that matter, hence the upgrade ).
PS, regulatory requirements are EU/NL. From what I can see, current installation doesnāt ground anything to the metal boat hull, not the 48V propulsion battery, not the 48V house battery, not the 12V basic loads battery. On shore the shore ground connects to the onboard AC outlets and the 3-phase propulsion battery charger, off shore the (non Victron) Inverter ground is also connected to the onboard AC outlets but not to neutral and neither to the hull. All in all everything seems to be isolated from everything else.
@UpCycleElectric I suggest you get a copy of the standard for electrical systems on small craft, I think this applies to up to 24m hull length, no idea what standards are for >24m and I believe this is what EU craft should conform to. This allows a DC system to be either connected to hull ground for metallic vessels or completely isolated. The relevant standard is ISO13297, Small craft - Electrical systems - Alternating and direct current installations and this covers AC to 250V and DC to 50V nominal. Then there is also ISO 23625, Small craft - Lithium-ion batteries.
My advice is to hire a qualified individual to at minimum to design your electrical system and probably install it for you as well.
You donāt know, what you donāt know.
Online forums are helpful for question about settings or operation questions, they are not the place for electrical or system design, as we donātā know what we donāt known about your project, and you donāt know whether the advise you are getting is valid.
Reading again, I would expect neutral and ground to be connected in yhe shore power supply, and if you have a Victron inverter that this has a ground relay that closes when there is no ac input.
Iām going to replace the old installation with Victron equipment. Propulsion and house power will stay fully separate and yes indeed shore power is grounded neutral to ground on shore (but not to hull onboard). The MultiPlus II will do the same once shore power gets disconnected and the first thing to consider is to either ground the MultiPlus II to the hull permanently (with possible ground loop issues between hull and shore) or over a secondary ground relay. Iām also looking in to adding an isolation transformer in front of the single MultiPlus II but not (yet) in front of the 20kW 3-phase (fully isolated) propulsion battery charger.
One thing to keep in mind is that there is no diesel/petrol engine onboard and even though I do not assume the Sevcon motor controller fully isolates motor from propulsion battery, the whole DC side of the propulsion system is fully isolated from the rest of the boat. And with the Sevcon always switched off when shore power is connected, I suspect no ground loop issues there (through motor and prop) but I will measure all of that with a Megger to make sure. Also testing for motor housing and/or Sevcon housing to be grounded to hull.
The fun part will start when testing for EMI issues during boating, I had to solve a massive 12kHz audio system interference problem on another boat with sort like propulsion system before. The interference was overlooked/unheard by the boat builder but not by the young guests while boating, I had to use a frequency analyzer myself to spot it, old ears will do that. That case was quite interesting with the interference path from motor through Sevcon to propulsion battery straight through a Victron isolated DC-DC charger to the 12V system powering both a bow thruster and the audio system. Luckily current project does not have a bow thruster and neither a DC-DC charger.
PS, the 12kHz beep issue on the soundsystem was solved by adding a LCR circuit between motor ground and the propulsion battery (-). It originated from the Sevconās HF Flux Vector PWM control loop. Iām glad I could not hear it but it must have been horrific for those youngsters Iām sure.
I will certainly check the standards . But that wonāt solve the actual dilemma I am facing: to keep propulsion and house battery separated or to consolidate them into one. I strongly lean towards keeping them separated for all but one reason: Victron integration. It comes across as a false dilemma to me, to decide such a basic design topic on the sole requirement to be able to fit into Victronās monitoring platform.
I think the whole boat page development is loosing most of itās attractiveness if there is an implicit requirement for the propulsion battery to be charged by Victron equipment. That is just not realistic in my opinion, there is a huge fleet of existing electric boats that could benefit from Victronās ongoing development of marine integration capabilities, for which the owners will never ever be willing to dish their existing high power charge equipment for Victronās, just to fit in.
But we will see. All power paths are actually measured so Iāll try using virtual devices or add a secondary venusOS on a rPi, Iāll find a way.
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. But that wonāt solve the actual dilemma I am facing: to keep propulsion and house battery separated or to consolidate them into one. I strongly lean towards keeping them separated for all but one reason: Victron integration. It comes across as a false dilemma to me, to decide such a basic design topic on the sole requirement to be able to fit into Victronās monitoring platform.