The nitty-gritty of the present system is, of course, more convoluted. The built-in cables
from the charger are only AWG 2; all the rest of the battery cables
The negative from the charger connects to the start battery, which is close to the charger; the positive runs via a 1/0 extension to the house bank. The connection of the 2 to 1/0 is made at a battery fuse(!). I was going to run both charger cables to the house bank, using a PowerPost connector, and of course fuse the positive at the battery. And I would add a busbar for the negatives.