Alternator and LiFePo battery question

I wonder what triggers 'battery saver mode' in a modern Ram. Does it have a ring sensor on a battery cable?

I've added hall effect ammeters to my engine compartment battery, one on feed from alternator +, and the other on the ground cable, but they said something like a 140F maximum temperature for the sensor, which helped inspire me to insulate the battery ( group 31 Northstar) from underhood engine heat and ventilate it to outside engine compartment.
My K type sensor in free air above battery rarely goes 2f above ambient. On engine shutdown the sensor just outside the battery enclosure hits 145f and takes an hour to fall below 100f, where the sensor inside enclosure was 72f the whole time on a 70f day. At speed that sensor is basically same as ambient.

My other battery bank are 2 Deka intimidator gc-2's that I pulled from a boat at 4 years old, which got new Lifelines, and while they together, have much lower cranking amp rating than the single group 31 Northstar, can still accept well over 120 amps when well depleted, as does the Northstar. The 50 amp charge limit on many drop in Lithium batteries is a bit of a deal breaker for me, with a system designed/optimized for fastest possible recharging of lead acid.

Obviously the time my existing batteries could max out an alternator is limited. I do want to be able to run a 1600 watt tablesaw from my System. I want the alternator's to be feeding ~1200 of that load, but this is when they get the hottest, Idling maxed out, parked. Only in drive foot on the brake is worse regarding heating.

I don't really have the need to do this now, nor the inverter that could power it anyway, only the desire for such capability.

While boat engine rooms are usually not greatly ventilated, at least their radiators and AC condensers are not contributing to the heatload in the engine room, like on a vehicle sitting in traffic on a 100f day.

I once made a powerpack with a 125Ah lifeline gpl-31Xt as the heart, and used 1/0 gauge cable from 2013 Rams' alternator + stud to it and ground cable to alternator mounting bolt. not sure the amp rating of that alternator but after several minutes of 100+ amps into the depleted lifeline, the alternator at idle, with hood up, shot with an IR gun was 220F, and stayed there as the voltage was lowered.

There is a difference in my vehicles rpm with it in gear, foot on the brake, as opposed to in park or neutral, that 75rpm difference in rpm makes for a significant difference in heating and output.

I've not really tested both alternators at max output into both battery banks when depleted. Generally one bank or the other is full.
I still have V belts and one chrysler alternator, and one Nippondenso. The ND alternator has 2mm more distance between the belts, and even though I got the alignment pretty good, I want the separation between belts on the ND alternator to match the Chrysler alternator and crank pulley before trying to acquire matched V belts.

My existing single V belt, is from before I removed AC compressor and replaced it with second alternator. When I did this, I found the original alternator location had its pulley 6mm out of parallel alignment with crank pulley and ac compressor pulley, yet I was still able to max out that alternator at 122 amps with just a single v belt, though if damp and cold it would slip and squeal.
I often crank my voltage regulator to about 13.2v before shutting down engine, when I know the alternator the next morning will be maxxed out feeding a depleted battery. If I dont then squealing is guaranteed until I crank down the voltage. I also like to let the engine oil circulate for a bit before the alternator adds the 2+ HP load to the engine.
My voltage regulators are switched on by oil pressure, the original VR inside engine computer is tricked with a resistor into thinking it is still attached to alternator. Other wise check engine light illuminates and engine runs crusty. I also have to keep voltage below 14.8v as 30 seconds of 14.81v will illuminate it.