I have another question about DVCC … i know it‘s often discussed …
I used this feature to limit the maximum charging voltage to 53.8V, otherwise two of my 5 battery packs would experience significant cell drift. This works perfectly as long as I don’t feed into the grid! If I activate grid feed-in or DESS, it no longer works reliably. It is clearly overcharging (up to 0.6V), then the system notices it or the solar pressure is less and the system temporarily corrects it automatically. But this happens way to often a day.
Any ideas to correct this behavior or what to change …
Sincerely
BO
3x5kvaMPII+RA200A+SmartShunt+Cerbo+5xDelongHS51200 connected via bms-can
No, since it say‘s there: „Note: When DC-coupled PV feed-in excess is enabled with ESS, the DVCC system will not apply the DVCC charge current limit from PV to battery. This behaviour is necessary to allow the export. Charge voltage limits will still apply. (What in my case doesn‘t work!)
Charge current limits set at the individual solar charger device settings level will also still apply.“
And Batterien life was Not enabled.
As a side note: I have had this problem from the beginning with fw releases over 12 months. Whether public or beta. Playing around did not lead to a solution. Of course I could restrict it to bms level, but in my opinion this would not be in the spirit of the inventor.
Exporting requires overvoltage, the system adds a 0.4V offset to get the chargers to work. For tested batteries this isn’t usually an issue as it will get drawn down.
What nick said, if you want DC Feedin, the Voltages of all DC-Participants have to be like Battery < Multiplus << MPPT, so the current/power flows from mppts to the multiplus and not to/from the battery.
But knowing this, you could try to lower your chargevoltage in 0.1V steps down to a value where your battery is actually reaching 53.8V by beeing “overcharged” with regards to that artifical lowered value, but not going beyond that to eliminate issues of the BMS with that.