I finally decided to try the new Solar and Wind priority feature that Victron offers with the MP/Quattro inverter chargers. I have watched all of Victron's videos and read all the documentation. There is still one question I have that I couldn't find the answer to. When you are using multiple inverter chargers, do all of them have to have the solar and wind priority setting activated or just the primary one for the feature to work?
Here is some information about my system. It consists of two Quattro 5KVA inverter chargers programmed in split phase. They are connected to a Cerbo GX for monitoring and control. I also have a VE-Bus smart dongle connected to them. The rest of my system includes three MPPTs (two 150/70s and one 150/100) connected to 3390 watts of solar, 1080 amp hours of Battle Born batteries at 12 volt, a 1000 amp Smartshunt for battery monitoring and a 500 amp Smartshunt for DC load monitoring. Additionally, I have a Phoenix 12/1200 inverter dedicated to one circuit in my RV (the residential refrigerator). All of these devices are also connected to the Cerbo via VE Direct and VE Direct to USB cables.
Yesterday (2/16/24), I enabled the solar and wind priority feature on both Quattros. I set the sustain voltage to 13 volts on both units as the Victron documentation recommends for Lithium batteries. I enabled the feature through VE Bus System Configurator and uploaded the configuration file to the Quattros through the VRM remote configure feature. The Quattros accepted the new programming without issue.
The Quattros are in my RV that was plugged into 50 amp shore power and my battery bank was already at 100% at the time the programming was updated. The system immediately went into a charge cycle (which is typical when the inverter chargers are reset). I thought the Quattros would shortly after go into Sustain mode once they sensed the batteries were already at 100% SOC.
I checked the Quattros in the device list on my Cerbo and saw the new menu item for the Sustain mode called "Charging the battery to 100%" was present. This menu item showed "In progress" rather than giving me the option to activate the item manually. The red bar was also added to the left side of the battery icon on the main GUI page of my Cerbo and it showed the two white arrows pointing up like the system was trying to fully charge my batteries. I assumed the system was attempting to start the batteries at 100% SOC before it went into sustain mode. I left the system to do its thing and came back to it today (2/17/24 approximately 20 hours later) to see what it was doing. My Quattros were still charging the batteries. They were in float mode, but the system voltage being shown by the battery Smartshunt was showing absorption voltage for some reason. (It was a rainy day with full cloud cover at the time I checked the system. I did not look at what state the three MPPT's were in to see if they were the cause of the absorption voltage (which I should have), but the batteries were still at 100% so I don't know why the MPPT's would have been in any other mode than float. The "Charging the battery to 100%" menu was still showing "In progress". For some reason, the system never went into sustain mode and the voltage remained at absorption level even though the system showed the Quattros to be in Float mode and the batteries were at 100% and had been fully charged all day.
I switched the Quattros to Inverter Only mode to let them ignore shore power for a period of time. After the batteries had drained to about 95% SOC, I switched the Quattros back to On. They immediately went into Bulk charge mode and began charging the batteries back to 100%. No matter what I did, I couldn't get the system to go into Sustain mode.
Because the system was in Float, but producing Absorption voltage to the batteries, I decided to change the programming of the Quattros. I removed the Wind and Solar priority from the slave inverter to see if this resolved my issues. I let the battery state of charge drain down to 95% before I uploaded the new programming. Once the new programming was implemented, the system went into a Bulk cycle until the batteries were at around 99% SOC and then switched to Absorption. I have a 5 hour absorption time in the programming (per my battery manufacturers recommendations because of the large size of my battery bank). The system hasn't had time to go into Float mode yet, so I don't know if the voltage will drop to the float level as expected. The system still has not switched to Sustain mode. I will check again once the Absorption set time completes
Both my Quattros and my Cerbo are running the latest firmware releases (not Beta).
