Yacht setup with Older Multiplus, Mase Genset Auto Start/Stop?, SoC accuracy and AC Input 1 ignored

DIY
, , , , , ,
1

Hi to the community, first time on the new site and struggling to find answers compared to the old site!
I have 2 systems aboard our cruising yacht (all are Victron unless otherwise stated!)
I have a few issues and queries as to what might or might not be possible, questions for each system below that system description.

12VDC system, comprising 4 x 220Ah 12VDC Victron AGM, which runs the main DC systems onboard including navigation, lighting, pumps, etc the 12VDC system has an old Phoenix Multiplus 12/3000/120 - PMP012302000 serial no:07120800322.
A BMV-712 smart batt monitor with 500A shunt, connected to a Cerbo GX with GX touch 50 (I was using Venus OS on a raspberry pi, but in high ambient temps, the power connection melted… so not doing that again!)
Solar charging is through 1 x MPPT 100/50 with 530W of solar and 1 x MPPT 100/20 with 275W solar, all linked with VE Direct cables.
The engines each have a 100A belt driven alternator, with one engine using a Sterling Power Products AR12W alternator regulator to maximise output.

Mains charging for the 12VDC is done through the Multiplus, which is powered via a manual changeover switch from either the onboard Mase 3.5i 230VAC (+/-2800W) genset or direct from the 24/5000/120 Quattro2 (most of the time the Multiplus Multi-control is set to Charger only with the current limit set at 0.0. Obviously the Quattro 2 only sees this as a 230VAC AC Load, not as an inverter/charger, as the 2 AC systems are completely separate)
I believe the Multiplus is too old (see above model number and serial no) to be integrated/monitored/controlled by the Cerbo GX and only has a multi-control unit connected that I can manually switch and control (see above). I have left this fitted and ready to be connected only as an “emergency” inverter (solely feeding a twin outlet socket after an RCD) so, should the 24/5000/120 Quattro 2 (see 24VDC system below) fail, I have some redundancy to run some of the 240VAC systems using this connected with an extension lead.

12V system questions:

  1. Cerbo GX control/monitoring of the 12V Phoenix Multiplus, is it possible based on it’s age? I seem to remember from the old forum there was a minimum firmware requirement but can’t seem to find this info now, the Cerbo does not recognise any AC input to the Multiplus when I am using shorepower, is there a setting or a victron product that would allow the Cerbo to register this info?
  2. The power assist function does not appear to work on the Multiplus, previously when this inverter was in use, it would not operate power assist with the 2.8kW onboard genset, either the inverter would work or the genset, but the power assist feature would not, although I believe this size/age of multiplus had the feature?
  3. I have tried to trouble shoot this, but with no luck and am looking for advice on how to further test what the fault may be, or a setting to change to make it functional?
  4. If there is an actual fault with the power assist feature and I were to replace the Multiplus with the latest model 12/3000/120-16. I believe this could then be controlled and monitored by the Cerbo GX?
  5. But, is it then possible to integrate the 2 Cerbo GX’s to communicate with each other? (both are connected both via the VRM and the LAN and also to the NMEA2000 network of the boat to share PGN information with the chartplotter etc.)
  6. In the case of fitting an updated Multiplus, is there a way to then utilise the power assist feature to have the primary 24/5000/120 Quattro 2 power assisted by the 12/3000/120 Multiplus rather than switch on the diesel generator? (this would enable me to use more of the solar/stored power I have more efficiently)

Next, the 24VDC system which uses 3 x 200AH 24V Victron Smart LiFePO4 for storage, controlled by a Victron Ve Bus BMS V2 connected to a 24/5000/120 50-50 Quattro 2 which is used to provide main power to the onboard 240VAC system.
The battery monitor is a BMV-712 smart batt monitor, connected with VE Direct cable to Cerbo GX with GX Touch 50
This has 2 x Smart Solar Charger MPPT 100/30 each with 2 x 430W solar panels in parallel (rated 42Vmp) connected to the Cerbo GX with VE Direct cables.
As a Quattro 2 there is a shorepower input and generator input (same genset as above), with 2 AC outputs, one AC output feeding the onboard system, the second (only active on shorepower) is only connected to the hot water service.
There are also 2 x 12/24 15A Isolated Orion Smart TR DC-DC chargers wired to allow charging of the 24VDC system from the 12VDC system when the main engines are running and the voltage is high enough.
The system runs DVCC (set up as per guidelines in manual) and also in “Sustain” mode (Solar/Wind priority) all the time, we are plugged into shore power, but I want to keep the batteries in best condition possible.

24VDC System questions

  1. The BMV-712 is selected as the primary monitor, but there seems to be an issue with the SoC accuracy. I see the batteries go from +/-60% to 100% in as little as 30 mins sometimes with the solar charging at a good rate. And then at sometimes around 55% the BMS will shut down the entire system as it seems to sense the batteries are “empty” the only way to restart the system is to start the genset, the Quattro will not sense the shore power even if plugged in and restart. Is this most likely a settings issue? Or where should I be looking?
  2. Has anyone got experience of getting a +/- year 2009 Mase 3.5i generator to be controlled by the Cerbo/Quattro 2 for auto start? I have been struggling to find information on required wire colours and terminals and what the start and stop controls/timings should be.
  3. On the “Advanced” menu for the Quattro 2 through Cerbo GX/GX Touch running firmware v.3.53 there is “AC Input 1 ignored” and “AC Input 2 ignored” both are set to “No” I believe this setting relates to “forcing” the Quattro 2 to be in Inverter only mode under certain conditions by “ignoring” the shorepower or genset power even if it is there? I think this would be useful for my system as currently I switch manually to “Inverter only” or “On” to try and manage the batteries better, whereas if I was able to set the conditions (say ignore AC Input until SoC is below 30% or similar) it would be useful, can anyone guide me to a clear explanation of how these settings work?
  4. Can this AC Ignore be changed through the Cerbo GX settings, or only through Victron Config?

There are other queries, but these are the main ones for now if anyone has advice it would be much appreciated

Many thanks

2

!!
I would have a serious look at rationalising the power system - Keeping things simple helps enormously.
My preference would be to move 90% of the battery storage capacity to 24V, All of the solar charging to the 24V system.
Dispose of the 12V multiplus, and use 1 inverter to provide all of the AC.
Use a 24/12V dc/dc converter to cover the dc loads required.
either replace the alternator with a 24V alternator, or use 12/24V dc/dc converters to have engine charging of the House bank.
You can then use the 24V multi to charge the house bank from the generator or shore power, using an isolating transformer for the latter.
If you wan to get any interaction between 2 Venus OS devices, then you are going to have to write some custom code - and to load this onto the 2 devices. This would not be an easy task, as the data would need to be transferred between the units using MQQT (?) over the LAN.
You have the AC redundancy in the ac from the generator, so keeping a second inverter for this is not necessary. Also 3kW at 12v is not efficient.
Ignore AC input: This is normally a virtual switch function, and it then allows you to set rules for when the AC is used, if present. Having the 2 AC in on the Quatro allows you to use one for the gen and the other for shore power. I think the ignore ac in can be manually over-ridden from the Venus menu, not used this myself. The VS rules are set from the VEConfigure software.
On our yacht which we had for 11 years, all of the house dc systems were 24V, and also some of the navigation systems. 12V was reserved for the radios and the engine starting system (separate). This worked well for 12 years and 57,000 sea miles.

see the batteries go from +/-60% to 100% in as little as 30 mins sometimes with the solar charging at a good rate. And then at sometimes around 55% the BMS will shut down the entire system as it seems to sense the batteries are “empty”
This probably indicates a problem with the batteries. With lead, it would indicate sulphation, but with lithium, it could indicate several issues:

  1. If the batteries are old, and had many cycles, then the charge voltage will rise early - before 80% SOC is reached…
  2. If your charging current is too high, then the battery protection systems will disconnect the battery from the bus, allowing the bus voltage to rise steeply.
    The DVCC function should be enabled to let the BMS control the charging current to allow the batteries to balance properly. If this persists, then take the batteries out and have them tested for capacity. Out of balance will also cause an early disconnect on discharge.
3

A battery monitor jumping to 100% too early and then running out of power when charging by solar is often a sign of incorrect settings in the battery monitor. See the FAQ linked below. The title matches your observations.

https://community.victronenergy.com/t/shunt-battery-monitor-jumping-to-100-or-reporting-a-high-soc-when-the-volts-are-low-and-or-the-bms-has-disconnected/88

4

Thank you for that link and for taking the time to answer, it is much appreciated.:

Based on what you wrote I have checked and here is how the settings were configured:

  1. Set to 600Ah, so correct
  2. Was set for 27.4V so low, have reset to 28.0V
  3. Correctly set at 4% (equates to 24A)
  4. Charged detection time was 5 mins, have now set to 6…
  5. This has changed in the app, options are now “Keep SoC” “Clear” and “Set to 100%”, was on “Set to 100%” now on “Keep SOC”
  6. In the 2 solar controllers expert mode is not enabled, so I would need to enable it to alter the Tail Current option. 4% of 600Ah is 24A so my assumption is that I could set the Tail current to say 20A in each solar controller and that would meet the criteria, or do I need to set each one to 10A to give a combined 20A?
    I have attached (hopefully) a screenshot of what it looks like before I make any adjustments.

20250129_113012652_iOS
20250129_113012652_iOS1290×2796 309 KB

Again, many thanks, I will see how it does tomorrow

5

Thank you, as always if one had the time, money and a blank canvas…
I am simply trying to optimize what I have without spending a huge amount for a full refit/modifications and most of it is fairly new, even the 4 x 220Ah AGM’s were new only 3 years ago and are performing faultlessly (the only let down is the old Multiplus with the power assist seeming not to work, but as I asked, that might just be a settings issue)

The LiFePO4 batteries are less than 2 years old and are still in good condition, and as they only run the onboard 230VAC, I am very happy, for redundancy, to keep both the systems working as best I can set them up.

I believe the 3(2.5)kW at 12V on the original Multiplus would be perfectly adequate if the power assist were working to give a combined 5.3kW when the genset is running, which is, from what I can ascertain how the boat was originally set up back in 2009… hopefully some of the suggestions by @pwfarnell will help me get further down the trrack!

6

Your low Charged voltage setting is exactly per the FAQ so that is most likely why you got to 100% when you were not really at 100%, so that should be sorted.

Point 5, I will update the FAQ to reflect the new option, thanks for this.

Point 6, having looked at your settings, you have the Victron Lithium Smart batteries where the absorption ends after a fixed 2 hours rather than the tail current, hence you can ignore my advice on this point. I will make a note in the FAQ on to reflect this.

See how you go.