HUGE thanks to @nworker
for inspiration and research on this. I just wired in a similar setup. The main difference in my install is that I’m not looking for a a second battery or even a backup for winching. I just need a house battery that charges from the solar on my rooftop tent and/or the alternator. This is to power my fridge (a Dometic CFX3 75DZ). So I did not need to route a huge pair of Cu wires to the front. I just ran one #6 alternator line which I brought up under the rear seats rather than directly into the storage tray. Much easier to seal with a 9/16 hole and a grommet plus some 3M 5200 quick dry. See picture below. Even with all the electrical hardware in there, I still have just enough room for most of my recovery gear.
Also, the Victron stuff costs a bit more but it is really slick. Nice app/ interface.
Here is a vid of the solar.
Letting the fridge run all night put the battery at about 95% of full in the morning but it charges up quickly once the sun comes up.
Here’s the alternator wire coming through the floor pan under the rear seat (passenger side). This is super flexible multi strand in silicone insulation.
I used 1-3/8” grommets to get the wires into the tray. One is the single #6 alternator wire. The other is the #10 circuit powering my cooler
You can see the MPPT solar controller at left and the alternator controller at right. The batteries and battery controller is at center. The battery pack is held in place with aluminum angle on 3 sides bolted thru the plastic tray. The wood block keeps it from moving fore and aft.
Victron energy DC-DC (alternator) Bluetooth charge controller.
Victron energy MPPT Solar Bluetooth charge controller.
Lynx LiFePo4 100 amp hour prismatic battery with included Daly Bluetooth battery management system (BMS).