Here's a good read on batteries....
https://www.expeditenow.com/blogs/how-to-kill-your-batteries/#.Wn4RRdxOmf0
Wish E/O had somebody this battery smart.
Keeping warm is an issue well discussed here on EO.
Use the search feature and you will find a plethora of threads, or click here for an excellent blog from our resident expert >>>>>Expedite Now Trucking Magazine - Keeping Warm Out There