I'm thinking of adding a second battery - most likely an 8.2kW. My current battery is 5.2kW. So the new battery has to be the first in the DC chain and the master. So I can either move the AC3.0 inverter and 5.2 battery - putting the new 8.2 under the inverter with the 5.2 under the 8.2 or I can change the current DC wiring. So the question is - what is the maximum length of DC cable allowed?
Slartibartfast You're unlikely to be able to get hold of a Batt8.2 as the new stock is Batt9.5s. The newer stock has to be installed using pre-crimped cables, so the maximum length is set by the manufacturer's cables, which you buy when you buy the battery. The actual physical siting of components doesn't really matter as long as the inverter is connected using the manufacturer's cables to the Batt9.5 and then daisy chained from there to the Batt5.2. You will need two new sets of cables with Batt9.5 lugs on one end and a crimped ferrule on the other to go into the AC3 (from Batt9.5) and Batt5.2 (from Batt9.5). The answer to cable length is determined by the maximum current drawn (60A for AC3) and the maximum acceptable voltage drop. Cable of 10mm2 should be OK for short runs but longer runs would need 16mm2.