loosewheel wrote:The “AC coupled” is probably what I'm querying.
Hi loosewheel, going by the specifications, the X1-LX3600 is a grid tied inverter. It will be AC coupled to the Hybrid SK-SU5000E. The way I would expect your system to work is as follows...
The LX3600 will produce AC energy which will be used in the house or exported to the grid.
The SK5000E will produce AC energy as will the LX3600, and the SK5000E will also charge the battery pack if the house is not using all the solar production from both inverters. If the LX3600 is meeting house demand, the SK5000E will be able to charge the battery bank at the maximum programmed amperage rate provided the SK5000E is making adequate power from it's own solar generation to do so.
The system should be fitted with either a separate meter or a current clamp on the grid supply, and feedback, from which ever device is fitted, will feed back to the SK5000E to tell it whether energy is going to the grid or coming in from the grid. If energy is coming in from the grid the SK5000E will use battery power up to it's maximum capability to limit imports from the grid. If energy is going to the grid and you are export limited, the SK5000E should be configured to limit it's output to control power going to the grid.
If you have been export limited to say 5kW, your battery pack is charged, your house is using very little energy, and your solar system is producing it's maximum, what will happen in that the LX3600 will produce all that it can, and the SK5000E will limit it's power output so no more than 5kW is sent to the grid. Note, you may not be able to limit power from the LX3600, but it should be sized so it alone cannot exceed the export limit.
What I do not know about your SK5000E is whether it can use it's solar generation as well as excess AC generation from the LX3600 to concurrently charge the battery pack if solar generation from the SK5000E is inadequate to charge the battery pack at the programmed amperage rate.
I am in the process of doing similar to what you are doing, and my approval has placed an export limit of 5kW on my system. I am using 2 hybrid inverters (different brand to your inverters, but same basic operation) so I have a backup hybrid inverter in case of failure, however, my battery pack only feeds one inverter, and my second inverter will be doing exactly what I expect your LX36000 will be doing. Below is an image of my connection layout which may give you a better understanding to confirm with your installer your system configuration. Your system might be using a current clamp to feed info on grid power level and flow direction back to the SK5000E instead of a meter...