Can't find any specific advice on this.
I understand the reasoning behind having it as close as possible to the aux/leisure batteries, but I can't find any further definition of what would be considered too far away.
I've got a lovely vented metal space underneath my passenger seat that would very nicely fit the requirements of the DC-DC being in a well-ventilated area, mounted vertically on a non-flammable surface... but my battery bank is at the back of the van, around 3.5m away.
Uno problemo, or should be good, with 16mm2/6AWG cable?