You car battery
Cold Craking Amps (CCA)
The environment you live and most often drive in often plays a key role in determining what kind of battery you should buy. Batteries with higher CCA ratings--defined as the discharge loads measured in amps that a fully charged battery at -17.8 degrees C can deliver for 30 seconds while maintaining the voltage above 7.2 volts--work better in colder climates and vice versa.
The Reserve Capacity rating is the number of minutes a fully charged battery at 26.7 degrees C can be discharged at 25 amps until the voltage falls below 10.5 volts. When shopping for batteries, more RC is better in every case.
Low-Maintenance Versus Maintenance-Free
These are the two most common types of batteries. While maintenance-free is obviously more convenient because of the lack of preventative maintenance needed, these batteries also often have substantially longer lives, greater overcharge resistance, and recharge faster. This variety, however, do go "dead" more often. Some manufacturers have added a third type of car battery, a dual battery with switchable emergency backup cells.
A group size defines the battery's outside dimensions and the placement of the terminals on them. If you see a battery with a combination of numbers, this means that the battery may fit two different model cars--34/67 may fit both Ford and Chrysler.
Determining the "freshness" of a battery is sometimes difficult, so try having a trusted mechanic or motorhead friend take a look at it before purchase. A battery that is more than six months old should never be bought because by this time it has likely begun to sulphate--the creation of lead sulphate that cannot be converted back to charged material.
To ensure that your battery keeps buzzing and your wallet stays relatively full, buy it from a trusted brand. Here are a few well-known manufacturers to get your started: