Just try your best to get the car to operating temps once or twice a week and you'll be good. Is this car parked in the garage? If so, just charge it once in a while.
I got one of these at Canadian Tire when it was on sale. Reviews suck but so far I haven't had any issues for the past year charging 6 cars and a boat. I get the cars to full charge at least once a month especially during winter months when I don't drive them. I've only driven the 1M about 3 times last year and the batteries are still in great condition.
http://www.canadiantire.ca/en/pdp/mo...-0111525p.html