My installation consists of shorepower going to a Victron iso transformer then into a multiplus. I found that today the multiplus wasn't working as a charger due to high grid voltage.
I've inferred that the winding ratio is around 1.06 (which also matches a similar post of another user having issues with high voltage trip) from measurements. Assuming that the 1.06 ratio is within manufacturing tolerances (can someone from Victron confirm?), what can be done to deal with high grid voltages in Australia.
In aus, the 230v nominal can swing up to +10% and comply with standards (so, 253v is permissible, and was what I measured today from the grid). When this happens, the iso output is at 253*1.06 = 268-269v. The multiplus charger subsystem does not turn on, I believe due to the AC high connect limit of 265v. The inverter subsystem appears to work fine off the battery, and I can talk to the multiplus through VEC3.
If I lift the AC high connect to 270v (assuming VEC3 lets me....) there will be no hysteresis for the AC high trip. I could also try to lift the AC high disconnect to 275v (again, if VEC3 lets me) but I don't know what internal margins are there in the multiplus before magic smoke comes out due to component overvoltage. Can Victron or someone whose been through this advise?
Specifically, while AS limits the positive swing to +10%, it is quite possible for the localised voltage to swing even higher due to local influences (including ppl feeding to grid...) I would like the configuration to be robust against these scenarios - the charger doesn't need to function if the swing is > +10% but the AC-in should be disconnected before internal damage occurs.