Buying a Battery
By Mike Bumbeck/autoMedia.com
Cold Cranking Amps - CCA
Before your inner cheapskate prevails, remember that a battery must have enough power to turn over the engine. This cranking power is measured in Cold Cranking Amps [CCA], and is the standardized measured amount of cranking power that a given battery can deliver at 0° Fahrenheit. CCA is of particular concern for those who live where winter temperatures can dip below zero. Engine and transmission oil becomes thick as molasses at these temperatures. Turning over the engine will sometimes require more CCA than measured at 0°. Select a battery with a higher than required CCA rating if the vehicle is operated in colder than zero degree climates. Never select a battery that has less than the CCA required by your engine. A few extra is better than too few.
Reserve Capacity - RC
This is a very important measurement. The Reserve Capacity [RC] is the measure of battery strength when the going gets tough. RC is the amount of time the battery will deliver maximum amperage before discharging altogether. A good example of RC in practice is trying to start a stubborn engine. A battery with a high RC rating will have enough power in reserve to get through tough situations such as stubborn engines or accidentally leaving the lights on while at the Pigley Wigley. Since the measure of RC is taken at warmer temperatures, it is of great importance to select a battery with a higher than required RC rating if the vehicle is operated in colder climates. The extra battery power waiting in reserve can help when you really need it most.
Remove and Replace
Hauling the battery out of the engine compartment and into the auto parts store for a like-for-like comparison is one way to choose a battery, but is not always the most reliable method. Unless the vehicle was purchased new-by-you there is no guarantee the correct battery was there in the first place. Compounding confusion is that time and battery acid are usually not kind to any identifying labels. This is where ideally you talk to a counter person and tell them what kind of car you have. The larger big box stores may have replaced humans with a frayed battery catalog, usually missing the one page that has which battery your vehicle uses. When buying a battery choose one with the highest quality and CCA/RC rating your budget can afford. In general selecting more battery power than you need is better in the long run than choosing just enough. Knowledge is literally power when it comes to buying the right battery.