Starter battery relocation to underhood (cross posted)

I posted this in the NCV3 Talk forum, but, realize that is should probably have been posted here.

I'm just starting a conversion of my 2017 Cargo Van.

I want to use a lithium house battery, which I understand is more sensitive to temperature especially cold.

Has anyone relocated the starter battery to under the hood, and put their house battery in the floor where the starter battery currently is?

I plan on a second alternator, and completely isolating the second alternator and house battery from the Sprinter circuits.

NBD drawing from LFP when cold.

But **charging** while still frozen can kill them dead.

An insulated box with a thermostat-limited silicon heating pad under the batt is not expensive.

And temp sensors as part of your protective relays setup.