Already decided next season I'm getting heated clothing. Google heated clothing or
http://www.thermologicgear.com/you will find lots of it.Most runoff of lithium batteries that are rechargeable. I just wantashirt/jacket linerand socks. Not terribly expensive for just those items. Seems like lots of companies design clothes like this for bikers.
My main goal is to reduce the necessarylayers as I generally feel very bulky late season and I hate that when bowhunting.