I am installing a set of MG Lithium Batteries (4x304Ah, 24v) in a boat. The boat, being slightly older, has a very nice electric system with plenty of redundancy where chargers, generator control, AC input is based on separate units. Inverters are only inverters, etc. Installing a Quattro ora Multiplus would mean changing the architecture of the system completely, altering the electric panel and potentially being dependent on a single Multi unit with fewer backup options. And I would prefer not make these many changes.
I was initially quite clear in may mind that I would use the MG LFB batteries with 2 x 100 A Skylla-i chagers and the MG BMS. As I have learnt more in this forum, I have begun to doubt if the Skylla-i offers enough flexibility not being DVDC capable. My specific questions are:
In a situation where the boat is at the dock, will I constantly be cycling the batteries because the skylla-i only affords on/off control? Would this be different with a Multiplus? In other words, will the Skylla carry loads when there is mains power available?
Will the AC input of the Skylla be visible in the GX device?
Will I be better off getting a Multiplus in charge only mode… (much bulkier option of I want 200 Amps?)
It is always quite complex to implement a solution with maximum redundancy; even if it is one of the technical solutions that I prefer despite degraded performance
according to the data sheet yes and if the current is not sufficient it is possible to put several in parallel ; They will be synchronized via the CAN-bus interface.
I think so, since there is the VE.CAN interface it should be possible to control the charger via a Cerbo GX
from what I have seen a multiplus is necessarily more compact than several chargers in parallel; after that it is up to you to see if the available space allows the installation of several chargers to meet the need.
I would prefer Multiplus or Quattro in place of Skylla-i for sure. But, if you insist to use Skylla-i, please see the link below to connect Skylla-i to the BMS system of MG Energy Systems.
In principle using the Quattro instead of multiple Skylla is reasonable and offer more current for similar space. HOWEVER be aware that the GX device can only control one group of Quattro/Multiplus. When multiple units are used on a single VE.Bus network they must operate in Parallel/Split or 3 Phase mode and combination thereof. You cannot have one unit being used as charger and the other used as an inverter. This is frequently the case when we deal with traveling boats that needs to switch between 50 and 60Hz.
One option to allow that mode of operation is to have 2 separate GX devices one for each of the Inverter/charger. Both GX device listening to the same BMS network. Alternatively a secondary Inverter/charger can be monitored on a single GX device using the MK3 device, BUT this would be for Display only and when using Lithium battery bank, the charger cannot be controlled by the DVCC function. This has to be done externally using digital ATC signals to turn the charger ON and OFF.