I use a lot of cordless tools on a dailey basis 18v and 24v. most sit out in the cold trailer overnite , I know for a fact that the batteries run at a less rpm when cold ,and they dont charge untill they warm up. (the charger just blinks in a no charge mode) To day i drove several errands and i seem to get better milage the longer i drove and noticed more help from the batts once everything was warmed up.Does anyone notice this with there hihy or other vehicles. Also do the batts weaken when the sit a few daysin cold weather ?...joe