Very informative post - thank you.
I have the same i.e. 3 batteries and I think i can upgrade another 5 to give me the maximum of 8 in the group max?
I am slightly confused about the maximum current capacity as its states the cable connectors are rated max 120A but how many batteries max out at 120Amps?
If you go over the 120A you have to allow an added cable [to make a pair 2 x 120A = 240A ] going to the inverter? Thanks