I got up early this morning to review more COC's sent to me - I get moaned at by the AiA guy if I say I write a report on an installations CoC - only...
The way I wire up the batteries, from the fuse holder to the battery there is 2 x 25mm cables, one feeds the top of the rack and the other the bottom...
Stick with the 25 mm sq cables for your battery connections since they match your battery's rating. For the fuse holder to inverter connection, a 50...