If your car battery is dead or even weak, you're not going anywhere. It is the leading cause of starting trouble, whether because of lights left on, a charging system problem or other cause.

Sometimes it is just that the battery has outlived its usefulness. But even at best, a healthy battery in 80-degree weather has only half of its output when the thermometer dips to zero.

When shopping, remember that a battery is rated by cold cranking amps (CCA), indicating its power and the reserve capacity rating (RC), which indicates how long your car's accessories can run and still have enough power to start the engine.

Since starting a car in cold weather can take up to twice as much current to turn over a cold engine, cars in colder climates would benefit from a higher CCA rating. Check your owner's manual for the original equipment manufacturer's (OEM) minimum requirements needed for your car and select the battery adequate for you needs. Buying one with an excessive CCA rating may be a waste of money.

In every situation, more RC (reserve) is better, like a little extra in the checking account. The size and number of plates in a battery determine how many amps it can deliver. By having more and/or large plates, you can increase the normal life of the battery. This is what distinguishes a three-year from a five-year warranty battery.

Battery manufacturers build their products to an internationally adopted Battery Council International (BCI) group number based on the physical size, terminal placement (where you connect the cables to the battery) and terminal polarity. BCI and the battery manufacturers offer application guidelines that contain the OEM cranking amperage requirements and group number replacement recommendations by make, model and year of car and battery size, CCA and RC specifications.