It's a 105Ah lead acid EFB battery (enhanced flooded battery), no good for any fridge, might give you 1.5 days at most when camped up with a 40L fridge. A 60L fridge/freezer would flatten it easily within 24hrs. The Smartpass is insufficient for charging it with fridge use, need to add the Ctek 25A DC charger or better still an Enerdrive or Redarc 40A DC charger. A 200Ah litihum would be best for the Luna fridge. Trick is finding a drop-in that will fit the space where the auxiliary is or using a slimline format lithium in the cargo area.
Not to derail this too far, but I'm just not aligning with your power requirements...
For instance, in our Tacoma, we have a 92aH main battery (factory Toyota battery). This powers a 50L ARB fridge continuously. The only supplement is a 80W solar panel on the hood, that, at best, provides ~60W to the battery. Assuming ambient temps are below ~33ºC, this battery will run the fridge for >1 day and still stay >12.0V. Prior to the solar panel the fridge would disconnect at 11.8v after about a day.
Regardless, of that; I'm confused as to how the SmartPass120S wouldn't be capable of adequately charging the aux battery for fridge use when it can provide up to 120A continuously to the aux battery. EFB batteries should be able to accept a continuous charge rate of something along the lines of 40% of capacity, so about 45A (maybe 60A for a short while). This would mean it can recharge the depleted (50% SoC) EFB within 1 hour of driving. If you account for a substantially slower charge rate as absorption turns to float, it would still be within 2 hours of driving (or having the engine running, more accurately). The alternator has no problems outputting this charge rate at idle, so even parked up at camp while you are loading will roll into this time.
200Ah of LiFePO4 would effectively quadruple the available power (compared to 105Ah EFB), and while it would almost certainly fit (the Victron 200aH comes to mind due to its fairly small packaging, or the Dakota Lithium's new Group 24F 135Ah), seems pretty overkill to run the fridge alone.
It'd be at least double that in the field in summer.
