Sadly I’ll have to part with my DIY board.
Everything works flawlessly and is in great condition.
Battery is 5S4P and can be connected in series (10S4P). It has around 200 km clocked and is still performing as expected. I’ve charged the battery in parallel with hobby charger+ server PSU. It was charged around 15 times. I’ll supply the serial cable with 2x XT90 connectors for both batteries, 2x XT60 connectors for Focboxes and antispark XT90 key.
I have all the parts listed in the table below including quantities and prices without shipping.
I’ve edited the misunderstanding around the batteries.
It’s a ready to go battery - not 40x single cells. Both of them were spot welded with thick metal strips + the batteries are are placed in 3d printed 4 cell holders from my design (https://www.thingiverse.com/thing:2526936).