Multiple inverters, different brands on same grid ?

[Externet]

Hi.
Read somewhere that some inverters 'talk' to each other when outputs are paralleled to grid; and there is a limit of how many can be connected.

If the inverters are different brands, what happens, if they have no intercommunication, what happens ?
Some people sell their inverter that became undersized to install a more powerful one instead. Is that mandatory ? What to consider/know to simply add another ?

 

[Texican]

assuming this is grid tie only
the fact that inverters are different brands should not matter at all
I have an SMA and a growatt feeding the same meter

there are other considerations however when adding capacity
bus bar rating, position in the breaker panel, agreements with the utility etc etc

 

[mkimid]

many houses are sharing a transformer, and, everyone may have a different system.