We have recently installed two Victron NG LiFePO4 200Ah 25.6V batteries on our sailing boat (Amel SM), connected via two Linx Distributors (M10) and managed by a Lynx Smart BMS 500 NG.
Additionally, we have a Multiplus II 24/3000/70-32 inverter, a 6 kW generator set, and approximately 1 kW of solar panels regulated by two Victron MPPTs. All of these components are monitored through a Cerbo GX MK2 with a GX Touch 70 interface, and everything seems to be functioning well after proper setup.
Given that our maximum daily consumption while sailing is 80A, and considering the solar panels and generator production, we did not replace the engine alternator dedicated to the 24V service. Instead, we kept the existing 50A 24V alternator and attempted to organize the charging of the LiFePO4 batteries accordingly.
However, the alternator setup is still raising some questions, for which I would like to ask your advice. We have installed two Victron DC-DC Isolated TR Smart units (12A + 17A) to prevent alternator overcharge, and the alternator is protected by a Sterling device (see attached picture) in case of BMS failure or shutdown.
When connected to the circuit, the alternator does not activate. The electrician assisting with our installation believes that, because we have installed two isolated DC-DC units, the alternator does not “sense” the 24V and therefore does not start. One proposed solution is to add a 24V LA battery before the DC-DC units.
What do you think? Could this be the issue, or might there be another explanation?
Looking forward to your advice.
You MUST have a lead acid battery on the alternator discharge / input to the Orion chargers to buffer the voltage. People who have tried your set up without the buffer battery report large swings in alternator voltage causing the Orion charger to cycle on and off. The Orions do not allow reverse current flow so volt sensing may not occur. With the lead acid buffer battery you do not need the sterling alternator protector, the battery will do this. All Victron schematics show the buffer battery.
Thank you, as I cannot find any scheme/plan to install it properly do you know where I can get it?
Buffer battery need to be LA but what about min/max Ah capacity?
Thx again,
I have linked the manual below, installation is Section 4. You can also download this a pdf.
The buffer battery could be quite small like 50Ah, maybe a bit smaller.
Many thx !