What will happen when I use a Multiplus ii to inject into the grid and the batteries is fully charged and will go into float? The inverter will draw power from the charger or from the batteries (until the battery voltage drops below the float value, and the chargers will start again)?
It depends on your settings.
For example I switch on feed in DC PV excess, and i have with battery life kn to make sure my batteries get ti 100%. Then it will charge my batteries then start feeding back.
There are also Settings where you can discharge from your battery into grid.
