What you need to know before you buy a car battery?
Cold Cranking Amps (CCA)
The range is between 330 CCA for a small cars up to 920 CCA for a large cylinder engines.
This measures the battery’s ability to start (crank) an engine under low-temperature conditions.
A battery puts out
100 percent of its rated power at 26.6℃ (80 degrees F)
65 percent at 0℃ (32 degrees F)
40 percent at -17℃ (0 degrees F)
CCA is great for comparing battery performance in cold climate areas, but in hot climates lead-acid batteries with extremely high CCA ratings may actually have a shorter life than those with lower ratings.
Cranking Amps (CA)
The discharge load in amperes that a new, fully charged battery at 0℃ (32 degrees F) can continuously deliver for 30 seconds while maintaining a terminal voltage equal to or higher than 1.20 volts/cell.
Reserve Capacity (RC)
If listed, For a 12-volt battery (six cells), RC is the number of minutes it can maintain a voltage of 10.5 volts with a 25-amp draw; therefore, a “75-minute” battery lasts 75 minutes under these conditions. The bigger the RC, the better; modern cars with lots of accessories can benefit.
The range is between 4o AH for a small car up to 110 AH for a large cylinder engine and many accessories. This one’s a little tricky. Sometimes also known as the “C20” rating, usually you’ll see this on a deep-cycle battery sticker. It’s a measurement of how much energy a battery can deliver continuously for 20 hours at 80 degrees F without falling below 10.5 volts.
In the real world, “total discharge time and load applied is not a linear relationship. As load increases, realized capacity decreases. This means if you discharge a 100 amp/hr battery by a 100-amp load, it would not give you one hour of runtime. On the contrary, the perceived capacity of the battery will be that of 64 amp-hours.”
An SAE-specified measurement of the battery’s ability to withstand repeated discharge/recharge cycles. Deep-cycle batteries are typically used on race cars without an alternator that require a between-rounds recharge, or in a street car that sits in a parking lot for hours with a high-amp stereo system on and the engine off.
Most batteries have a date code, usually a long string of numbers and letters that show when the battery was purchased. One row of one- or two-letter codes indicates the month, the other row of numbers is the last digit of the year.
Standardized classification defining a battery’s physical dimensions and terminal position. Typically batteries with the same group number can be physically interchangeable.
Depth of Discharge DOD
An AGM battery has a depth of discharge of 80 % versus a standard flooded battery which has a DOD of only 50 %.