Interesting thread, I have the SDV8 2016 and have been thinking a Lithium battery to replace the stop start would be good. My rationale would be to have a live 12 v outlet in the rear to run a fridge. From reading it seems that a fridge can run for 3 to 4 days on a 48 Amp Hour Lithium. Seems there are some thin lithium's around for $500 that may fit the space , and since cranking amps are not required this would serve me well.