With such a variety of operational specs, sizes, and terminal locations for lead-acid batteries, it's hard to know which one to purchase for your specific application. Do you choose a battery designated with a CCA ratings or one specified using a HCA rating? We hooked up with 1-800-Battery to get a quick list of terminology to should shed some light on the battery manufacturer's performance ratings for fully charged, 12-volt (6 cell) batteries:
Battery Council International (BCI) Group Size: The BCI Group Sizes or Group Numbers, refers to a battery's maximum physical dimensions. These standardized sizes can be found in a BCI Group Sizing Chart. Group 31 for Light Commercial batteries, and Group 34 for Heavy-Duty Commercial batteries, are two of the most commonly found sizes for trucks and Jeeps.
Cranking Amps (CA) or Marine Cranking Amps (MCA): These two ratings are the same. They refer to the number of amps that a battery at 32F can deliver for 30 seconds, while maintaining a minimum voltage of 7.2 volts, or 1.2 volts per cell.
Cold Cranking Amps (CCA): The number of amps a battery at 0F can deliver for 30 seconds, while maintaining a minimum voltage of 7.2 volts, or 1.2 volts per cell.
Depth of Discharge (DOD): This refers to the percentage of the battery's total power that is discharged. A Deep Discharge refers to a DOD under 50 percent of the battery's potential, with some Deep Cycle Batteries capable of DOD's down to 20 percent. NEVER discharge a battery below 10.5 volts, as this will produce permanent damage
Hot Cranking Amps (HCA): The number of amps a battery at 80F can deliver for 30 seconds while maintaining a minimum voltage of 7.2 volts, or 1.2 volts per cell.
Reserve Capacity (RC) or Reserve Capacity Minutes (RCM): This refers to the minutes a battery at 80F can deliver a continuous 25-amp current while maintaining 10.5 volts, or 1.75 volts per cell
When purchasing a new battery for your truck (assuming you aren't using a custom box), the first thing to look at is size, specified in the BCI Group Sizing Chart. Also look at the number and locations of the battery terminals. The next choice will depend on your application's power requirements. Look at HCA ratings for hot climates, CCA ratings for cold climates, and CA ratings for climates that are moderate or fluctuate between extremes. For a RV, boat, golf cart, etc., where the battery will be drained without being concurrently recharged, make sure you purchase a "deep cycle" battery. These deep cycle batteries usually have a slower rate of discharge and may not be able to handle large cranking requirements, but they can handle large DODs for many cycles. If you are looking for a battery for an off-road vehicle that will handle large vibrations or the occasional upside down operation, then look for a sealed battery.
It is important to remember that batteries will need to be replaced every so often. In ideal conditions, a quality battery will last from eight to 10 years, but its lifespan is primarily dependent on how and where in your vehicle you will use the battery. Higher DODs would be capable for a fewer number of cycles than just partially discharging a battery. Remember to keep the terminals clean of corrosion and the proper balance of the electrolyte solution of unsealed batteries.
Lastly, look at the battery's manufacturer, as well as what type and length of warranty they offer. There are several well-respected companies that produce extremely durable and dependable batteries. Proper maintenance and operation will boost the potential of your battery's performance and lifespan.