Short on Time? Here’s The Article Summary

The article explains the importance of understanding and converting Cold Cranking Amps (CCA) to Ampere-hours (Ah) in the context of batteries, particularly for solar systems. It defines CCA as a measure of a battery's power output in cold temperatures and Ah as a measure of a battery's capacity. The conversion process involves using the formula CCA = 7.2 x Ah to convert from Ah to CCA, and Ah = CCA / 7.2 to convert from CCA to Ah. Understanding this conversion is crucial for selecting the right battery for a solar system, especially in cold climates where batteries may need to deliver more power to start engines.

The article also discusses different types of batteries, including starting batteries, dual-purpose batteries, and deep cycle batteries, highlighting their differences in terms of CCA and capacity. It concludes by emphasizing the importance of knowing how to convert CCA to Ah for selecting the correct battery for a solar system.

Introduction

If you’ve ever taken an interest in mechanics, you’ve probably run into the term “cold cranking amps” (CCA). Knowing how to use these units and how to convert CCA to Ah is crucial. 

Before we begin with the conversion process, we must understand the units as individuals. This gives us a better understanding of their relationship which can explain to us how to convert them properly.

This one isn’t as simple as knowing how to convert milliamps to amps and requires you to understand the units properly.

What Are Cranking Amps?

Cranking amps rate the output and capacity of a battery. They are measured under a specific environment: 0 degrees Celsius (32 F).

Cranking amps are the number of amperes a lead acid battery at that temperature can deliver for 30 seconds while maintaining a terminal voltage above 7.2 volts or equal to 1.2 volts per cell.

Cold Cranking Amps

A cold cranking amp, or CCA, is the most common way to describe the amount of power that a starting battery delivers.  

To be more specific, it’s the measurement of how much power a battery delivers for 15 seconds at -17.8 degrees Celsius.

It’s easier to start an engine in a warm environment compared to a colder one. Therefore, CCA measurements ensure that the battery has sufficient power to crank the engine during cold climates.

Take an RV solar system as an example.

Let’s say you’ve traveled upwards toward snowy climates and your solar system was already set up using an RV amp calculator. You have some 200W flexible solar panels, a battery, and an inverter.

Everything is going to plan until you need to start your RV’s engine or the battery in your solar system. When batteries are faced with extreme cold, starting them can take longer than usual.

The battery sends electrical energy to your RV’s engine, jumpstarting the electrical circuitry throughout the vehicle.

It keeps the current steady and stabilizes the voltage so that it can keep your engine running.

What Are Ah?

Let’s say we’ve used a house amp calculator to get an idea of how much power is being used in our house. 

We need a battery of the same size or larger to compensate for the electrical usage.

Battery capacity refers to the amount of electricity you can extract from a battery from one cycle of a fully charged battery to a fully discharged one.

You may notice on some batteries, alongside the voltage, have a reading in amp hours.

An amp hour is the amount of energy charged in a battery that gives you one ampere of current for one hour.

Most battery manufacturers don’t use the same measurement for calculating capacity, so this is where it becomes complicated.

If we take a 225 Ah battery measured at a 20-hour run rate, we can divide the Ah by the hours to be left with only amps. This leaves us with a value of around 11.25 amps.

This means that the battery is rated to produce that many amps for 20 hours straight. With this value, you can now convert volts to amps, or vice versa, if needed in an equation.

The more current you draw, the more you decrease the capacity of your battery.

But now that we’re clued up on the two variables in today’s topic, how do we convert one to the other?

Converting CCA to Ah

While the relationship between these two variables isn’t as simple as those used in a VA to amps calculator, the conversion and calculation are still pretty simple.

The formula states that cold cranking amps (CCA) equal the product of amp hours and the standard terminal voltage of 7.2V

This is what that equation looks like in mathematical notation:

CCA = 7.2 x Ah

This equation assumes you know the amp hours of a given device and are looking for the CCA. However, using some algebra, we can swap these terms to figure out the Ah of a device from its CCA. All we have to do is move the standard terminal voltage to the other side of our equation and it looks like this:

Ah = CCA / 7.2

Knowing how many amp hours are in a battery with a CCA rating allows you to find the correct battery replacement and tells you if your battery is suitable for your solar system

CCA in Various Batteries

We mentioned starting batteries, but CCA doesn’t only apply to them. Let’s look at a few other battery types that you may use in your solar system.

Starting Battery

A starting battery is the most common type of battery found in cars and RVs. 

It’s used to crank the engine and provides the power to lights and audio systems in your RV when the engine isn’t running.

What separates these batteries from the ones used in solar systems is that their plates are thin with a larger surface area. This means they aren’t designed to be used in deep-cycle applications.

Dual-Purpose Battery

These batteries can be used as cranking batteries as well as being used to power various loads in a solar system.

They’re common in industrial and residential areas and demand for them is increasing as technology continues to innovate.

Deep Cycle Battery

Finally, we have optimized deep discharge and cycled batteries. These batteries can’t provide strong cranking currents but offer excellent cycles.

After looking at the 3 different batteries, it's safe to say that dual-purpose or starting batteries work well if you’re looking for something with good CCA.

Conclusion

This conversion process isn’t used by many but that doesn’t make it impossible.

It’s still important to know how to convert CCA to Ah as it’ll help you with devising a battery for your solar system.

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