Using the kid for managing solar and Grid energy to maximise PV - RELAY install

[zimnismoboy]

Hi there all not sure if this is the right place to ask this question.
I have a mid nite kid b which supports aux output and also load disconnection and reconnection on various setups .
I have a small scenario that i would like to shed light on and maybe just need some input.
In an ideal world you have 2 or 3 days of autonomy for those that can afford a massive battery bank, i live in one of the sunniest parts of the world and we get almost 5.5hrs of usable sunlight during the day.
My battery bank is 12v running on a 200ah battery not the biggest but my night loads arent very big, take not im still on the grid .
We have times in the day when we are making good power from the array and that charges the battery and goes to float around 11am .
I would like to implement a system using the load out put terminals to manage a Double pole double throw 12v activated relay using the low voltage disconnect feature.
Essentially once the battery is charged i have excess 400watts of power and want to use this to run my day time loads in the house effectively making use of the panels and equipment with out depleting the battery stored charge.
So my idea would be to have the relay wired into my board and switching over my household loads like fridge and laptops and tv during the day, the KID will manage the voltage on the battery and if the battery starts being depleted, say sunset or cloudy weather or high loads i would like the kid to switch over back to mains, until such a point that the battery reaches charge again. saving the storage in the bank or battery for night time incase of power failure.
This effectively is a grid hybrid TIE if im not mistaken and would equate to saving power consumption from the grid as well .

Ive been trying to do a search but cannot find any information pertaing to this kind of setup maybe because the majority of the market can afford a SMA inverter that can manage this for them automatically.

Of course i would need to make sure the low voltage set point for transfer back to grid is set at a reasonable level around 12.5 volts as any lower then this and the battery is being effectively used to power those loads and not the solar panels .
This would also maximise the battery health as well because it wouldnt be cycling to hard and ensure the battery always remains charged and waiting .

let me know your thoughts and comments .Cheers.