I have dual quattros, and Octo GX with DVCC enabled, several MPPTs connected to the GX via ve.direct, and a smart BMS on canbus (MG Energy). The system uses DVCC not just for voltage, temp, and current sense, but also for charge control. When plugged into shore power, I get zero output from my solar, so have attempted to use Sustain Mode in the quattros to solve that, but so far it's not working very well.
So far, about 2 hours into enabling Sustain mode, the quattros are still outputting about 15ADC, "Charge to 100%" says "in progress", and my 1400W of panels are only producing about 50W on a clear, sunny day. The sustain voltage in the quattros is set to 26.6V, CVL from the BMS is 27.1V, and battery actual is 27.1V
So it looks to me as though the quattros are actively regulating to CVL of 27.1V rather than backing off and letting the solar do the work.
One possibility is that my AC input to the Quattros all comes in on AC1, and I saw in the writeup on this feature that the Quattros want shore power on AC2 and generator input on AC1, and that Sustain is ignored on AC1. This makes sense if you are using the quattro that way, but I am not. All AC power source switching is done externally, before it gets to the quattro.
And some more advanced questions:
Is there anyway to turn Sustain mode on/off via the GX, either in the GUI or via Modbus? Since all my AC comes into the quattros over a single input, I need to enable/disable Sustain based on whether I'm using shore power or am at anchor and running a generator. Taking a laptop into the bowels of the boat to plug in a dongle to change the mode is not particularly friendly.
Can the Sustain voltage be controlled via Modbus? I have not seen a parameter for that, and it would need to be writable. When the boat is parked on shore power for an extended time, I change the DVCC setting to limit voltage so the batteries are held below 100% SOC. It works great, but probably requires a corresponding adjustment to the Sustain voltage.
Any suggestions are welcome,
Thanks
