Well to start a diesel requires a large fully charged jump starter, I would rather take my chances with jumper cables. Your reference to dead batteries will take a lot to start.
When the batteries in our 2001 Ram CTD started to fail, jump start took 20 minutes of jump/charging it just cranked enough to get started. This is with mechanical injectors, usually took less than a full revolution to start. Your 2012 need to spin a couple revolutions to start.
Russ & Paula the Beagle Belle.
2016 Ram Laramie 3500 Aisin DRW 4X4 Long bed.
2005 Copper Canyon 293 FWSLS, 32' GVWR 12,360#
"Visit and Enjoy Oregon State Parks"