Cold Batteries Hold Charge Better

... but they don't deliver it as efficiently. That's one reason it can be harder starting your car in the winter. Unless you've kept your auto toasty warm in a garage (or live in a climate where it doesn't get cold), the battery may have trouble delivering the charge required to turn the engine over on a really cold day. Temperature is one of the factors that affects the rate of a chemical reaction. Batteries are electrochemical cells, so they behave predictably. The reaction that delivers charge proceeds more slowly at cold temperatures than at warm temperatures. Hot batteries delivery charge better; they also run the charge down faster. Two take-home messages from this are:

1) You can prolong the shelf-life of batteries by keeping them refrigerated (in a sealed container, to minimize condensation and risk of an electrical short when the batteries are used).

2) Expect hot batteries to run down more quickly; cold batteries to delivery a weaker charge. If you store batteries in the refrigerator, let them warm up before using them.

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Photo: Temperature affects how charge is held and released. (Eyup Salman, stock.xchng)