Last weekend I removed my batteries, cleaned out the trunk and checked water levels. Everything was great, and this weekend I am insulating the battery pack. It's been cold at night, 35F, and the batteries aren't too happy. Today I purchased two 2x8 sheets of 2" foam insulation and tomorrow I will rig up my new insulation box. This box will be twice as thick as my last box, and it will be easier to keep sealed.
I am also hoping to test my water heater this weekend. It's getting pretty cold out, but preheating the EV with the ceramic heater has worked fine the past week.