Thanks Tim, good to know & an excellent explanation.
So rather than replace my less-than-two-year-old SC80 that I'm very happy with, I have done the following to deal with the risk of a very low cranking battery:
- Lead with Ctek-12S to charge cranking battery through 12S (white) plug
- Lead with Ctek-Anderson to charge aux battery through Traxide rear Anderson plug
- Short cable on each positive terminal c/w 75A Anderson powerpole to allow aux battery to start vehicle if required by connecting the two leads together
Note: yet to actually build the last one but idea taken from 
 <this Disco3 thread>
How does that all sound? Obviously the newer SC80 is more straightforward but do I have most scenarios covered?
Cheers,
Scott
Photos: Ctek-12S lead  ----------------------------------------- and  Anderson powerpole charge cable
https://www.aulro.com/afvb/images/im...016/06/721.jpghttps://www.aulro.com/afvb/images/im...016/06/722.jpg