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What is the Difference Between Cold Cranking Amps and Reserve Capacity?

Batteries Plus Blog - Power - by Bryan Veldboom - updated on 5/13/2022

Truck going mudding

Battery failure is one of those things that all drivers dread. There's nothing worse than sitting there stranded on the side of the road, hoping someone will come along and give your vehicle a jump. Since vehicle batteries are more likely to fail in cold weather, the Battery Council International has established a series of standardized measurements that anticipate how well a car battery will perform in low temperatures. Today, we'll be discussing the difference between cold cranking amps and reserve capacity and what they tell you about your battery's performance.

Why Do Batteries Die In the Cold?

Cold impacts a car battery in a number of ways. It slows down the chemical reactions taking place inside the battery, which reduces the amount of electrical current it can produce. At the same time, the oil in your vehicle's engine thickens in low temperatures, making it harder to pump through the engine block and start your engine. This creates a situation in which your battery is working much harder to start the engine, while operating with less power. If your battery is over three years old or wasn't completely charged up to begin with, it's even more likely to fail.

What Do Cold Cranking Amps and Reserve Capacity Measure?

Cold cranking amps and reserve capacity measure different things. Here is a brief breakdown of how they're different.

Cold Cranking Amps

Starting batteries work to turn over your engine by delivering a high concentration of electricity for a short period of time. A battery's CCA rating measures the amount of current it can discharge and sustain for 30 seconds at a temperature of 0℉, while still maintaining a voltage of 7.2 volts. That means that a battery with a CCA rating of 250 will produce 250 amps for 30 seconds in a 0℉ environment, while a 400 CCA battery will produce 400 amps of power for 30 seconds at 0℉.

Reserve Capacity

Reserve capacity measures the number of minutes a fully charged battery can deliver 25 amps of power in an 80℉ environment before falling below the battery's minimum voltage. This tells you how well a battery can deliver energy over time independent of the vehicle's charging system. Since it measures how long it can deliver this energy, reserve capacity is measured in minutes. The higher the rating, the longer the battery can provide power. That means that a battery with a reserve capacity rating of 140, will deliver power for 140 minutes.

How Many Cold Cranking Amps Do I Need?

A battery's CCA rating is useful when trying to find the best battery for the type of the vehicle you have and the environment in which you'll be using it. Most car batteries will fall between 300 and 600 CCA. If you live in a particularly cold climate, you may need a battery with a rating between 650 and 800 CCA. Heavy duty trucks typically require batteries in the 800 to 1000 CCA range. In order to find the recommended CCA rating for your vehicle, consult your owner's manual or the manufacturer's website.

What is a Good Battery Reserve Capacity?

In addition to starting the engine, your battery also works to power additional applications like windshield wipers, lights, clocks, radio settings, alarm systems and any other onboard technology. A battery's reserve capacity rating will help you determine how long it can power all of these additional battery drains. If the reserve capacity is too low, your battery won't be able to stand up to these additional power drains and will die prematurely. Reserve capacity also tells you how long a battery can power the vehicle's electrical system if the charging system fails.

Typically, when you buy an auto battery, the emphasis will be placed on the CCA rating, rather than the reserve capacity. Reserve capacity becomes more important for cycling batteries like those used in boats and RVs. While the CCA rating is more important to your battery's everyday performance, it's still a good idea to consult your vehicle owner's manual for the ideal reserve capacity rating.

What is the Best Brand of Car Batteries?

X2Power batteries are engineered to be the longest-lasting, best-performing auto batteries available. They're manufactured using Thin Plate Pure Lead (TPPL) technology, which provides them with optimum CCA and reserve capacity ratings in the same battery. A typical standard flooded Group 31 battery will have an average rating of 925-950 CCA and 190-195 RC. An X2Power battery of the same size has a rating of 1150 CCA with a 220 RC. Shop X2Power car and truck batteries or browse our entire selection of auto batteries either online or at your nearest Batteries Plus location.

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