You just need to hard wire a 12v into the battery. In rear. Run a wire with an in line fuse.
One battery as much as we will be moving will be fine. Jump pack does not run fridge. It cracks car after fridge kills battery.
That would require me breaking into the body molding of the car and routing wire through the firewall. UGH. I am thinking that these batteries can do the job. Not 100 sure however.
This is the one I purchased. It has a 12v out up to 6amps. that would run the fridge.