I have 2 Multiplus-II 5k-70 parallel, connected to 6 x US3000, Cebro GX (2.62) and a Fronius Primo on AC-Out1. What I don't understand is why the MP-II stops working when they are connected to the grid and in 'Inverter' mode. They work when connected to the grid and in 'Charge only' mode. They also work when they are in 'Inverter' mode and NOT connected to the grid. Who can help me to find the problem why they don't work when connected to the grid and in Inverter mode? Dealer is saying they configured the Multiplus correct and can't find a wrong setting.
To test and to find the problem I exclude the cabling and the in-house circuit (also the Fronius) therefore I connected the Multiplus's directly from the Main grid circuit breaker to the Multiplus 'AC-In's (cables are same length, no fuses or busbar in between). On the AC-Out1 I directly connected a load (no busbar or breakers). When I switch the MP-II on it takes them multiple tries before connecting to the grid. When and if it succeeds the loading to the battery is very unregular and fluctuating. One of the multiplus is making a unregular fluctuating humming sound. After 2-6 minutes the MP-II shutdown (no error in the VRM portal). Sometimes they restore and sometimes they stay off.
All settings that I know of (from the manuals) are set. 'Limit Inverter Power' is switched off.
I am lost... why does it work in other modes and not when in Inverter mode?