apam

i flashed the SPF6000ES to the latest firmware 100.05/101.04 and the inverters seem much more stable.

One more thing, the overload bypass does not work in a 3-phase connection! It is the same for all SPFxx00ES.

The high voltage bus in the inverter has approx. 380 - 460VDC. It is the source of current for the inverter and battery charger and at the same time the place where all DC power sources meet. In very simple terms, the energy in this bus is accumulated in capacitors that have enough capacity to smooth out the current peaks created during regulation. The SPF 6000ES won't improve your condition, probably adding another inverter per phase might help, but that's just a guess I haven't verified.

The problem is in the inverters. I had 3 x SPF5000ES now I have 3 x SPF6000ES in 3-phase. The voltage drop when an intensive load is switched on is reflected in all inverters. This is related to a sharp drop in the HV bus level. Simply the capacity of the HV bus is not sufficient to compensate for the sudden increase in consumption or the control of the DC/DC converter is too slow.