Im starting a major up fit to my Jeanneau 440 electrical system. I'm replaceng the 4 type 31 lead acid 215ah with 4 Dakota Lithium 280ah type 31 size that will fit in the same real estate. I am also upgrading my alternator to a Balmar XT.
The batteries have internal BMS and I am still running lead acid starter batteries for my engine and generator so do I want a smart BMS or should I use a battery isolator to charge the starter batteries.
All of the different Victron BMSs are for connection to the Victron Smart lithium batteries, they receive info via Victron specific data cables. They are not for interfacing with 3rd party batteries. Some third party batteries will interface with the Cerbo GX via CAN Bus, see the attached list.
https://www.victronenergy.com/live/battery_compatibility:start
I think you should consider utilizing a DC-DC charger that will draw power from the alternator and use it to charge the lithium bank in a very controlled manner (customized for the LiFePO4 batteries) while keeping them isolated from the lead-acid start bank.
The upgrade of the Balmar is a good choice but I think you should use the Balmar MC614 external regulator or the Wakespeed WS500 external regulator. If you have a CerboGx the Wakespeed would be preferable because it interfaces to it directly. The external regulator can be setup for lithium profile and you could use an Orion DC-DC charger for the start batteries. Unfortunately the Orion does not talk to the CerboGx at all. I assume the Jeanneau has a thruster so that battery could be charged through a VSR between it and the starter battery. The same could be used for the genset start battery. That way the Orion will charge all start, thruster and genset batteries. The normal FET isolator used by jeanneau can be removed with that setup if you wish. Solar can charge the house system through a MPPT controller.
If you are using an alternator of over 100 amps capacity please consider a serpentine belt instead of a single V belt. The single V belt will cause a lot of belt dust and fail earlier than expected. The sepentine belt kit can be purchased from Balmar for all standard engines fitted to Jeanneau yachts. An important aspect of large alternators feeding very low impedance batteries like Lithiums is the provision of alternator temperature sensing. In the case of the Balmar MC614, the temperature sensor bolts to the alternator case and when the alternator reaches 100 degrees C, the alternator excitation current is reduced by 50 %. This is to ensure the alternator does not overheat if it is producing rated current for extended period of time in less than ideal conditions. I assume the Wakespeed works in a similar way.
I hope this helps.
You bring up a good point that--depending on the loads on the engine bank with the engine running--it may make more sense to have the DC-DC charger charging the engine bank than the LFP bank. You certainly need to ensure that the DC-DC charger has the capacity to cover all the engine bank loads--this is vital.
Rather than the MC-614, look instead at the MC-618. It has more advanced high alternator temperature mitigation control. Rather than the 614's one step control of 100% field current to 50% field current--which was really only designed as a fault condition mitigation--the 618 has much more refined control over the field current. The 618 also can interface with their network and bluetooth module to monitor & control the regulator from your phone and/or a standalone display.
If one has the MC-614 they can also use the belt manager as it will also regulate amp output to desired output. I believe the MC-614 is no longer available as the 618 takes it's place. Trevor Bird's suggestion with the serpentine belt is spot on.
From personal experience, I would not use a Victron Orion DC-DC charger for this installation. In a similar installation in an Oceanis 50, we have used a Victron Argofet to separate the charging to the house bank, bow thruster, and starter battery. We made a simple screen recording with commenting (In Norwegian unfortunately), but the point is still there. Check it out if you want. In the app; "Makspower Lading" is the house bank, "Oceanis Baugpropell" is the bow thruster and the "Oceanis Start LifeP" is the starter battery.
The house bank is a 1200Ah Makspower Lithium bank with internal BMS (12x100Ah Lithium), the starter battery is a 40Ah Lithium battery and the bow thruster battery is an Optima YellowTop 75Ah. I have previously used an Optima RedTop as a starter battery in this installation as well.
The Victron Orion DC-DC charger will only limit the charge current while the Victron Argofet will allow maximum charging to all the battery banks. The Argofet has no restrictions and the current flows to where it's the lowest resistance, and when batteries are getting fully charged, charged voltage evens out on all battery banks.
For the MC-614, in my opinion, I would derate it so that it can keep charging at a constant level without triggering the temperature charge reduction. Keeping it below 100 degrees C and allowing it to charge at a constant level instead of jumping up and down is in my mind a better solution.
Most likely, you'll find an electronic battery separator in your Jeanneau installed from factory.
Find the tradeoff that works for you.
