Finally got it together today. I moved the shelves into place on my own - only 46 kg each, and I didn't have to move them very far. I did it while wearing my safety boots! (Truth be told, I was barefoot
The two half packs are joined by 9 x 4 mm2 cables with ring lugs. The final + and - leads have to come from the other side. I didn't have the room to put them up the opposite side - bit of a design fault at the time of construction, but this does work, even if it's messy. The 9 x 4 mm2 leads are terminated inside a single 70 mm2 terminal lug which was crimped using a hydraulic crimper. When you have the right tool for the job, life is easy.
The - side goes through a 125 A fuse first, then to a 200 A max, 50 mV shunt, then a busbar. The + side goes through a manual isolation switch to a busbar where I've fixed a small 6 position fuse box. There is still room for another 50 mm2 cable to bolt onto this to the inverter (which has it's own fuse). The 6 fused circuits can be used for lights, fridges, motors, scooter chargers... whatever. I wanted to make sure this was a complete, 48 volt, 180 Ah off-grid storage unit ready to go. Never forget your fuses!!!
Next step is to fit the charger and do a final balance charge.