Hank85713 wrote:
Yes it is an insulator and my dealer said its mainly for cold weather and he advised to take off here in Az. I have had them on several vehicles and took all off and suffered no ill effects afterwards.
So its your choice to use or take off since its really not needed.
It's also for heat, which is worse than cold in general for batteries, but not an issue either way. I'm sure theoretically there's a small benefit.
Like most things, real world, not enough to make a difference and too many other contributing factors to battery life anyway.
Last set of quality batteries lived in my 07 diesel for 10+ years, no blankets and 2 winters in Alaska.