Hi Victron
Great systems you have but I have some suggestions. In South Africa we we have good rules for gridtie systems but the grid is unstable and this makes life difficult. In no particular order:
1) AC Coupled PV: It would be nice to differentiate the charging source and the limit of the charging source. When you have AC coupled PV you might want to charge harder from the AC coupled PV than you are allowed to from the grid. As an example the MP2 5kVA has 70A DC charger when paralleled for 10kVA you can charge with 140A DC. If connected to grid you must limit this in South Africa (depending on your municipality) to 3.5kW only. This limits your charging capacity from the AC coupled PV, maybe you can option that?
2) Dealing with SOC estimation errors: When running ESS on a managed BMS LiFePO4 battery you rely on SOC. Most BMSs are pretty bad at SOC estimation and they tend to drift with time. The only way to re-calibrate this is to charge them to their max voltage (~55V for 16s 48V system) and let the battery top balance and "reset to 100% SOC". This is all good an well when you have enough PV and the battery can get to 100% every 2nd day or so. When the battery is not fully charged for a week you can get situations where the battery is out by 25% on SOC in a week. One way is to force a scheduled charge once a week with ESS but the problem is you can only specify SOC in % and not voltage. It would be good to have the scheduled charge where you can say charge to 55v and stop once charge current is < 5A for example.
3) Delayed grid charge: I run the ESS and during night time I use stored power and set the min SOC for reserve. When the grid comes back it would be good to delay the charge on the battery from the grid somehow.
Thanks for all the great work!