Your regular 12volt battery does two jobs, powering all the electrical gizmos and gadgets in your car (like lights and the stereo) and starting your engine. The amount of power available for each is measured in cold cranking amps (CCA) and reserve capacity.
Both numbers are standardized in a group number, which you’ll find on your battery or in its service manual.
Battery Size
Car batteries are designed to fit specific vehicle models, and selecting the right replacement is crucial. A BCI code (or battery group size) provides information like physical dimensions, terminal type and configuration, base hold-down type, lifting edge, and other ‘little’ features that impact fitment.
Picking a larger battery than specified may physically fit, but could create problems if the vehicle’s battery tray or compartment can’t secure it securely. Conversely, choosing a smaller battery than specified could result in an insufficient power reservoir that won’t start the engine and run essential accessories.
Understanding key battery characteristics like chemistry, cold cranking amps (CCA), reserve capacity and polarity can help you decipher these battery specifications and terms. Look for this information in your vehicle’s owner’s manual, or ask a trusted local automotive service professional to help you make the right choice. Our inventory includes a variety of sizes for automotive, marine, lawn & garden, golf cart, and powersports applications.
Battery Voltage
It’s best to check battery voltage a few times each year (especially before winter). It’s also helpful to keep a record of the results over time.
Automotive batteries usually measure 12.6 volts at rest. This is called their “resting voltage.” Once the engine is running, the battery’s voltage will increase to a range of between 13.7 and 14.7 volts.
This is because the alternator will supply most of the battery’s energy while the engine is running. However, a bad battery may cause weird electrical behavior, which is why the battery voltage is important to know. It can help identify issues before your vehicle starts to act up and causes your check engine light or other indicator lights to turn on. You can test a battery’s voltage by using a multimeter with the dial set to the “voltage” setting. You’ll want to remove any surface charge from the battery before taking a reading. This will ensure that the multimeter is giving an accurate result.
Battery Cold Cranking Amps (CCA)
A battery’s CCA rating is an important measurement because it indicates how well the battery performs in cold weather. For example, a battery with a higher CCA rating can crank the engine of your car faster and keep it running even when temperatures drop.
To determine a battery’s CCA rating, scientists put the battery in a cold environment (0 degrees Fahrenheit or Negative eighteen degrees Celsius) and measure how many amperes it can deliver for 30 seconds while maintaining 7.2 volts of charge. CCA ratings are a good indicator of how much power the battery can produce under cold conditions, but it’s important to remember that more isn’t always better.
In addition, a battery with a high CCA can take longer to recharge and may have a shorter lifespan than a battery with a lower CCA rating. So, when shopping for a replacement battery, be sure to compare CCA ratings to Ah ratings. To convert CCA to Ah, use a multimeter and a hook.
Battery Reserve Capacity
Reserve capacity is the amount of time a battery can power a load without its voltage dropping to an unusable level. It is measured in minutes and is an important specification when comparing batteries.
This measurement isn’t as well known as cold cranking amps and often overlooked when buying a new battery. However, it is an essential battery spec for those who use their vehicle’s accessories for long periods of time or during extreme weather conditions.
To measure reserve capacity, apply a constant load of 25 amps to the battery and continuously monitor its voltage. Then, note how long it takes for the voltage to drop to an unusable level. This measurement is a good indicator of a battery’s health and can give you clues that it is nearing the end of its life. This information can help you make wiser decisions when selecting a battery for your marine, RV or other application that requires consistent energy.
