ES-Hybrid smart meter
The smart meter tells the inverter how much power is coming from the grid or going into the grid. Because the inverter knows how much power it produces currently itself it can calculate how much power is taken by the loads. If there is a battery in the system the flow into or out of the battery will also be taken into account.
Besides simply knowing what is going on the inverter can also adapt its energy production and the power transfer from/to the battery in a way that makes best use of all possibilities.
Usually the basic strategy is to produce as much as possible and feed power not consumed by your loads into the battery until it is full. If the battery cannot take all excess power the remainder is fed into the grid.
If you advise the inverter to limit power feeding to the grid it will decide in such a case to produce less power than would be possible.
You can also tell it (or the BMS) to keep a certain minimum energy level in the battery – buying energy from the grid if solar power was not sufficient for your loads.
You can even load the batteries from the grid – although this will not make much sense in most cases.
The video helps you to put the energy meter into place.
Note that this will usually be a location within your fuse box. Unless you are a professional or semi-professional electrician it would be wise not doing this yourself.
Even if you ask a knowledgable person to install the meter you should still double check that all connections are made precisely as described in the video. Pay special attention to the flow direction (0:33 onwards in the video). 90% of all problems have their cause in incorrect smart meter installation.