Had a quick chat with our DC Expert. When there is dcpv excess, there is actually no rate-based balancing happening. The inverters will use the same voltage setpoint, which should lead to a quite equal discharge to AC then.
Tiny differences based on different AC voltage, but not that huge.
So, what you should check:
- Is your L2 AC voltage significant different compared to L1, L3?
- are the DC connections of the multipluses “equal”? Length, diameter and overall resistance?
If the multiplus on L2 would have a significant lower resistance to DC, it’ll discharge more than the others.
How old is your installation, was this the case from the beginning, or just started recently? Sometimes fuses and breakers can go bad, but still conducting at a higher resistance (so, should eventually swap them between phases and see if the discharge remains L2 focused or moves to another phase)