You don’t need a Pi. You can install Venus OS Large and Node-RED will run directly on the Cerbo GX. I do run a couple of Pi’s instead of the Cerbo, but I also have another one with Venus OS on there for testing code before I put it on a live system.
This is what it looks like on my system. I have the scale node set to decrease the charge current above 13.6V. What this does is allow the system finish off the bulk charge without tripping a BMS or hitting the absobtion stage 1-2 hours before the battery is ready to start absorbtion. I dont know why this is not a feature already. I understand your pain and you could tune it so you dont even hit absorbtion and just remain in a bulk stage with a max voltage. As your system draws down the battery the current will ramp up.
