Ive got 2x150w mono panels, in parallel, about 2m of 6mm cable joining the 2 together, then about 4m of 6mm cable to the controller, then 4m of 6mm cable from Victron MPPT 100/20 controller into 1 x 130ah agm battery, ive never ran out of power yet, been off grid in a caravan for 2 years...