Listed below are some of the important factors you should consider. If you are unsure of the requirements in any of the details, check your vehicle service & repair manual or talk to a mechanic for the original equipment manufacturers (OEM) recommendations. It’s also a good idea to look for a hassle-free warranty that includes a free-replacement time frame.
Compare Deep-Cycle Batteries vs. Starting Batteries
Different vehicles and driving styles can place varying demands on your battery. It’s important to first determine whether a conventional starting battery will meet your vehicle’s needs, or whether a deep-cycle or AGM battery is required. Learn about the difference between deep-cycle and starting batteries.
Starter Batteries – Starting, Lighting, Ignition (SLI)
These batteries deliver a large burst of power for a short time as needed for normal engine starting. The battery is then recharged by the alternator. Unlike a deep-cycle battery, starting batteries are not designed to withstand multiple discharge/recharge cycles, and draining it can significantly shorten its life.
Deep-Cycle Batteries
These batteries are designed to provide a steady amount of current over a long period of time. Deep-cycle batteries can be repeatedly discharged and recharged without causing damage or shortening their life. They are well suited to powering numerous electronics and plug-in accessories, or other applications that place high demands on them such as marine.
Some deep-cycle batteries can be used for engine starting as well (these are sometimes referred to as dual-purpose) but be sure to check the CCA rating to ensure the battery has sufficient starting power.
Car and Truck Battery Group Size
This refers to the battery size that will best fit the physical dimensions, terminal locations and type required for your vehicle. The Battery Council International (BCI) assigns numbers and letters for each battery group size. Group size is typically based on your vehicle’s make, model and engine type. Although some vehicles may accommodate a battery from more than one group size, it is important that you use a battery approved for use in your vehicle. Consult a replacement guide to find the battery group size that works for your vehicle. Also, make sure your new battery will fit and be held down properly according to the vehicle manufacturer’s specifications.
Common Battery Group Sizes
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- Size 75: Most General Motors cars
- Size 65: Large-bodied Ford, Lincoln, and Mercury cars
- Size 35: Recent Honda, Nissan, and Toyota cars
- Size 34: Most Chrysler cars
- Size 34/78: Some Chrysler and General Motors cars
Cold Cranking Amps (CCA)
CCA is a rating used in the battery industry to define a battery’s ability to start an engine in cold temperatures. Generally speaking, it is easier to start an engine in a warm environment than in a cold one. The rating refers to the number of amps a 12-volt battery can deliver at 0°F for 30 seconds while maintaining a voltage of at least 7.2 volts. The higher the CCA rating, the greater the starting power of the battery.
Don’t Confuse CCA With CA
CCA (cold-cranking amps): This indicates how much electrical power the car battery can deliver to the car’s starter motor at 0 degrees Fahrenheit.
CA (cranking amps): This is another measure of electric current in the battery, taken at 32 degrees Fahrenheit. Generally, a battery’s CA rating is higher than its CCA rating.
Consider the CCA Rating if You Live in a Cold Climate
If you live in a cold climate, the CCA rating is a more important consideration than it is if you live in a warm one. Battery starting power deteriorates as the battery ages, so a battery with higher starting power should give you more confidence over time. Replacement batteries should equal or exceed the OE battery in ratings. Replacing a battery with a battery that has a lower CCA than the original equipment may result in poor performance.
Reserve Capacity (RC)
RC is a general indicator of how long a new, fully charged battery can continue to operate essential accessories if the vehicle’s alternator fails. It identifies how many minutes the battery can deliver a constant current of 25 amps at 80°F without falling below the minimum voltage, 1.75 volts per cell, needed to keep your vehicle running.
Do not simply select the battery with the longest reserve capacity you can find. Consult your owner’s manual to learn the recommended reserve capacity rating for your particular car model. Only choose batteries whose RC ratings fall within the recommended range listed in your vehicle owner’s manual.
Amp Hour (ah) and C20 Battery Capacity
Amp Hour or C20 is an indicator of how much energy is stored in a battery. It is the energy a battery can deliver continuously for 20 hours at 80°F without falling below 10.5 volts.
Battery Uses
In addition to car batteries, there are batteries available for all types of vehicles and applications. Other applications include marine, powersports, heavy-duty trucks, agriculture vehicles and golf carts.