I was told not to use lithium as a cranking battery also. I'm not sure exactly what you will have attached to the cranking battery. If you start having voltage issues on your electronics, or weak/no crank, it'd be the first thing I looked at. When my troubles started I pulled direct wires (oversized) from each unit to a master power cutoff and then to a dedicated battery. I carry jumper cables because I get flagged down several times a year for drained cranking batteries.