Optimistic Paranoid
Adventurist
Truck Camper Adventure has an interesting DIY article on building a heating system for Lithium batteries to permit charging them in sub-freezing temperatures.
https://www.truckcamperadventure.com/lithium-battery-rv-heating-system-mod/
https://www.truckcamperadventure.com/lithium-battery-rv-heating-system-mod/