Cold weather is negative, but focus on the positives.
Batteries are a lot like people in winter; they like to stay warm and be fed regularly to keep their internal chemical reactions happy, even if they’re getting less exercise. We compensate with multiple holiday feasts and beer. Your car’s battery needs its own annual routine.
Any car battery stored for a long period of time will suffer self-discharge, even in moderate climates—so southerners with garage queens aren’t exempt. Real damage can result when a depleted battery’s electrolyte meets freezing temps, cracking the internals and case. Proper battery storage with a charger avoids both problems.
Buy the right equipment.
Conveniently, effective battery chargers cost less than buying a new battery every year. (Translation: You have no excuse.) Just don’t cheap out and get a “dumb” trickle charger; models that have a float, storage, or maintenance charge mode are preferred. Often called tenders—many of which are made by the Kleenex of the charging world, Battery Tender—they have intelligent circuitry inside to cycle on and off and keep the battery at the right level without overcharging. They’re perfect for winter lay up or any kind of long-term vehicle storage.
Prepare the patient.
Before attaching the leads, inspect the battery’s terminals and cables, cleaning off any corrosion and replacing worn parts. This is also a good time to apply some dielectric grease to prevent further corrosion. Then it’s as easy as slapping on the included alligator clips—red is positive, black is negative. If you’re fancy, you can permanently install a quick disconnect. Just be sure the charger is unplugged or off before making the connections.