Dual Inverters Needing Dual Batteries?

[DoingMyBit]

My installer was re-doing my system today to get our dual-KH10.5 inverters into parallel mode properly. They then saw that some of the house load was being powered by the battery, but some was being drawn from the grid. The Fox guys on the phone suggested that the ECS battery pack needed to be split into two, so that each inverter (in parallel mode) had batteries attached to it. Is this correct advice from Fox? Can't an ECS stack just be attached to the Master Inverter in parallel mode, and leave the slave to just handle the additional panels that would be too much had it been just a single inverter set up...?

Poor installer has done so many snags on this job, I'm hoping that this is errant advice, and it might just be a CT / wiring issue...

[Dave Foster]

In 'theory' you should be able to have a single battery stack, but when running in parallel there will likely be a lag whilst the inverters work out what work is being done by each inverter and balance accordingly but it's likely you will see strange effects as you have noticed.

The best advice by far when running inverters in parallel is to have 2 inverters of the same size, each with a battery pack of the same size as Fox have said.

[DoingMyBit]

Thanks Dave. Yes, still seeing strange effects - battery is discharging to grid as well as house load this morning, despite the system all being in Self Use mode. The installer is going to separate out the stack, so hopefully that will resolve everything. Thanks for your help!