I was just recently gifted these really nice deep cycle batteries from a friend and retired dweller. This is my first time putting together an electrical system. I think I just need help tying up loose ends. I tried to round everything up. Not entirely sure how much power the heater and speakers will pull until they’re installed. A little confused about how much power it will take to maintain the 2kw vevor heater I have.

Power budget Dual 12 inch speakers 300w x 3hours = 900wh 6 house speakers- 150w x 8 hours = 1200wh Heater-120w x 1hour (?) = 120wh 4 lights- 100w x 5hours = 500wh Phones- 10w x 3 hours = 30wh Total:2.75kw

2750w / 12v = 229Ah

2 12v 116Ah firefly oasis MCF batteries wired in parallel to get 232 Ah.

Alternator/starter batteries and solar panels (3, 1x1 panels) into renogy MPPT dc to dc charger into auxiliary batteries into 3000w inverter

50amp charger Where do I need fuses? What amp fuse? What gauge wire and where?

What is the simplest and most cost efficient way I can piece this system together?