This frigid weather (in large areas of North America) is a good time to top off the charge in the accessory battery. Mine was reading 12.38 volts today, not long after the car was driven. Constant use of the steering wheel heater and seat heater(s) probably helps to drain it more than usual, on top of the reduced capacity caused by cold weather. So again, it's a good time to recharge it fully, and to top off the washer fluid reservoir as well. (And good luck doing that without overfilling it!) I put in a wired connection that can be used by both the Diehard 2 amp and Battery tender Jr. 0.75 amp maintainers, and I'm glad I did. I just wish Nissan had thought more about people wearing gloves when they decided how easy to make access to the inner hood release with the charge port open...