So I tried this and I think that this is the cheapest way to build a solar storage battery system to your house. A lot of other batteries like Tesla Kia BMW and polestar is also compatible batteries to integrate with this emulator. 
My mistakes and missunderstandings:
1: I uncomment the battery type to the serial lilygo in the arduino ide. This makes flashing impossible.
2: I crossed the serial wires between the board, missreading of the wiring diagram.
Thanks Lars😍 who did se that☺️
3: Flashed the boards with different firmware releases.
Costs:
Nissan leaf battery 24kWh: 16000sek
Lilygo boards, breakers etc approx 2000sek
Tot: 1539€ 17/8 -24
86€ / kWH👍🏻 Real kWh!!
Where to buy?
I search the site bildelsbasen.se for used batteries, and mostly I buy them from Norway.
Links to Dalathegreat who has developed those stuff for us, all credit to him 👌🏻
You will find all the parts, wiring diagrams and links to buy the stuff you need for this project on his site.
https://github.com/dalathegreat
https://youtube.com/@DalasEVRepair?si=iva_6xdJwQiUorRk
Thanks Dala for your outstanding work!