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CCA to Ah: A Working Formula to Convert the Values

Why do you need to convert cold cranking amps to amp hours? You don’t unless you are going to buy a new car battery. Car batteries feature plenty of specifications and you have to get them right for the smooth running of all the electronics in your car. The CCA to Ah conversion comes handy to determine whether a battery will be the right fit for a specific car.

What are Cold Cranking Amps (CCA) and Ampere Hours (Ah)?

The CCA rating refers to a battery’s ability in low temperatures, or more precisely, how efficient it is in kicking an engine off when the weather is cold. As simple as it sounds, it’s clear that this rating is more important when you live in a cold region where the temperature often drops beyond zero degrees.

From a technical perspective, this rating indicates the amp number that a 12V battery can deliver for 30 seconds straight under 0°F. The battery has to maintain at least 7.2V of power during this period. A battery with a higher CCA rating means that it provides a greater starting power.

The amp, on the other hand, is the measurement of the electron flow and current within a conductor. One Ampere refers to one coulomb of electrical charge that transmits all across the conducting item within a second.

cold cranking amps to amp hours
CCA rating indicates battery’s performance in cold weather. (Photo Source: car)

The Ampere rating is the battery operation threshold that gives an estimation of the battery charge. From this rating, you can calculate how long the unit will last without recharging. A battery unit will have this rating written out on a label. The measurement unit is either Ampere Hour (Ah) or milliampere hour (mAh).


Why Do You Need to Convert CCA to AH?

If you live in a cold region, the CCA rating is useful in determining the better battery for low-temp conditions. The rule of thumb is the higher the rating, the higher the capacity and power.

You need to convert CCA to amp hours to find a battery’s capacity. A great number of units use the CCA rating to refer to the power of starting an engine at a certain temperature range, typically between 30°F and 32°F.

You can choose a more powerful, better battery by knowing the starting power, but the CCA to Ah conversion is necessary for knowing its capacity.

How to Convert CCA to Amp Hours?

When you purchase a new car battery based on the CCA values, you will need to convert it to Ah. The problem is there is no direct correlation between these values. You won’t get a single formula to make the conversion.

Worry not! You can still get an approximate if not the exact value. The rule of thumb is to divide the CCA by a 7.25 constant. Some manufacturers may provide their own formulae. If you find one in the owner’s manual, use that. Otherwise, the following strategy may work.

For example, you need to calculate the amp hours in a 740 CCA battery. One straight formula is:

Ah x 7.25 = CCA

It means multiplying the Ah value with a constant 7.5 to get the equivalent CCA value. For 200 Ampere hours, the CCA rating will be 1450. But you want to convert CCA to Ah, the opposite given in this formula. In that case, you need to work this formula around to find the Ah value.

Ah x 7.25 = CCA 

Ah x 7.25/7.25 = CCA/7.25

Ah = CCA/7.25

So, if you purchase a 740 CCA battery, its Ah value will be,

Ah = 740/7.25

Or, Ah = 102

This 740 CCA or 102 Ah battery will run 12.75 hours when running at 8 amps of voltage or 10.2 hours at 10 amps of voltage. The higher the CCA rating, the more the Amp value of a battery.

convert cca to amp hours
Ah value indicates how long the battery will run. (Photo Source: practicalmotoring)

The Final Words

Even if there is no direct association between these two values, you can convert the values between each other, if necessary. When you can calculate the Amp hours from a CCA battery, it will be easier to find the correct replacement when your car battery goes bad. Or, you may have a battery showing the Ah rating only, and you need to convert it to CCA to have a better idea about its performance in the cold season. Just use the method mentioned above.

A battery is one of the most important components of the automobile mechanism. All the electronic components depend on it. Also, the battery’s power and efficiency are vital in starting the engine. Both CCA and Ah ratings are important as the former will help you understand if the battery is suitable for cranking the engine in a certain low-temperature condition and the latter gives an idea about the lifespan of the battery.

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