Normally when I am driving in HV mode the battery charge will fluctuate up and down a couple miles and continue doing that for the trip. Today on the way to work I decided since it was cold I was going to use HV mode hoping not to use any of the battery charge. As I was driving on the hwy I notice the battery charge was going down very slowly and not staying within a range like it normally does in HV mode. I am wondering if this is a normal condition in very cold weather. I did try hold down the HV button for a couple seconds to see if it would start charging the battery since the battery was below 60 percent. The message I got was I needed to plug the car in to have it charged. Anyone else have this issue?