What Are Car Battery Cold Cranking Amps and Reserve Capacity?

A car battery wears out just like any other battery and eventually needs to be replaced.  But one battery size does not fit all. Indeed, there are a number of factors that determine what car battery you should use in your vehicle. There are a couple of things you should understand when looking for a new battery: one is car battery cold cranking amps and the other is car battery reserve capacity. Let’s take a look at these two important factors when battery shopping.

What Are Cold Cranking Amps?

We’ll start with the cold cranking amps meaning when applied to a car battery rating.  This can be thought of as the potential power output used to start a cold engine.  So how many cold crank amps do I need? The number of cold cranking amps you need depends on your vehicle and where you live, specifically how cold it is where you live.  The two factors are that the colder an engine is, the more power it takes to turn the engine over to get it started.  It has all that cold, sluggish oil to contend with on top of the normal struggle to overcome engine cylinder  compression.  The other factor is that the chemical reaction inside the car battery itself that creates electrical energy is less efficient in the cold.

Basically the colder it gets outside, the more power is needed to start an engine, but the available battery also power drops.

If you live where it’s cold, you need a car battery with more cold cranking amps than you do where its moderate or hot.  You should always get at least as many cold cranking amps as the manufacturer recommends, but may want to upgrade if you live where it gets real cold. Wondering how to increase cold cranking amps? The answer is buy a battery with a higher CCA rating from the start, as the CCA amount can’t be changed later. You will likely never regret buying a battery rated for more cold cranking amps than your vehicle specifies, but you will most certainly regret buying a battery with less.

An important note: Batteries may also list the Cranking Amps – CA – number.  It is the Cold Cranking Amps – or CCA – that is the important number here.  CCA is the number to use in your comparisons.

Now with all this talk of cold temperatures, it’s important to note that heat is the real enemy of long battery life.  In other words, the damage that’s done over the hot summer months shows up with the increased demands on the battery when the weather turns cold. That’s why it is important to have your battery tested often or whenever the seasons change.

What is Battery Reserve Capacity?

What is car battery reserve capacity? It’s a measurement of the number of minutes of reserve power the battery has at a given load.  The number is more important these days because of parasitic drain.  Parasitic drain is the battery energy that’s used when the key is off.  So, the power drawn by the security system, the remote start system, even the power the computers require to maintain their memory. Modern vehicles are crammed full of systems that are still active even when the ignition key is off.

Reserves are also needed when you make very short trips.  If you are not driving long enough for the battery to recover the energy it used to start the engine, you will need that reserve capacity for your next trip.

So when new battery shopping go with the minimum cold cranking amps and battery reserve capacity recommended by your manufacturer then upgrade if you feel like your situation needs more.  Talk with your parts or service advisor about options.  If you need more from your battery, a larger capacity battery may be called for. Just remember that physical battery size also matters so if you do choose to upgrade make sure the new battery still fits in your original battery mounting location.

A car battery is a big ticket item, so the warranty gives piece of mind.  Be sure to ask about the warranty so you know what you’re getting. And finally make sure to check out our Car Batteries 101 Guide for more information on automotive batteries & battery maintenance.

Check out all of the batteries available on NAPAOnline or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on cold cranking amps or CCA battery meaning and answering what does reserve capacity mean on a battery, chat with a knowledgeable expert at your local NAPA Auto Parts store.