A car battery is typically rated in amp-hours and cold cranking amps, mostly for lead-acid batteries. This is important because knowing your battery’s capacity and starting power will help you determine whether you should get a new one or choose a better car battery charger.
But do you know how much power your car battery has? And do you know what amps are?
Well, if you’re looking for the answer to these questions, you’ve come to the right place!
What Is An Amp?
First things first: What does “amp” mean? Amp is short for Ampere. An ampere (abbreviated as A) is a measurement of electric current. It refers to the amount of current that flows through a circuit or wire. In short: amps are like water flow—the more amps there are flowing through something, the more current there is (and vice versa).
If you’re used to thinking about electricity in terms of volts (like we do with our house power), then amps may sound unfamiliar.
For a simple answer: the average car battery has a capacity of about 40 to 100 amp-hours (Ah). That’s enough to start most cars and power accessories for a while!
To better understand this: If you have a 12-volt car battery with a capacity of 100Ah (Amp-hours) and want to know how much energy it can store, you’d multiply 100Ah by 12V. That would give you 1,200Wh (Watt-hours)—the total energy storage capacity!
How Amps Work
The amp, or ampere, is a unit of current. It’s often measured in conjunction with voltage and power. If you want to know the number of amps your circuit is pulling while it’s operating, use this formula:
Amps = Watts / Volts
So if you’re using 100-watt headlights and you’ve got a 12-volt car battery supplying your circuit, then the current flow through it will be:
Amps = 100 watts / 12 volts = 8.3 amps
How To Locate Your Car Battery’s Capacity and Cold Cranking Amps
Finding the ampere-hour (Ah) rating and Cold Cranking Amps (CCA) on your car battery can be a little tricky, but with a little sleuthing, you’ll be able to do it in no time.
First, look at the label on your battery. You might see “Ah” followed by a number for the capacity, and “CCA” followed by a number for the Cold Cranking Amps. For example, “60Ah” means the battery has a 60 amp-hour capacity, while “600CCA” means it can provide 600 Cold Cranking Amps.
If you don’t have access to the label, you can also look up your battery model online or consult your vehicle’s manual for this information.
If you need a label, try looking on the website for the car manufacturer. Some companies list this information online so that you can see if it’s compatible with your car before purchasing one.
So what about the capacity and starting power of our car batteries?
How Much Capacity Does A Car Battery Have?
The average car battery has a capacity of 40 to 100 amp-hours (Ah). This means it can theoretically provide 1 amp for 40 to 100 hours, or 40 to 100 amps for 1 hour (though in practice, you wouldn’t fully discharge a lead-acid battery). This is important to know if you need to figure out how long your battery can power devices.
For example, if you want to run a 10-amp device on your car’s 60Ah battery, here’s a rough calculation:
60Ah / 10A = 6 hours
This is a simplified calculation and doesn’t account for factors like the battery’s depth of discharge limitations, but it gives you a general idea.
The higher the amp-hour rating, the more energy the battery can store. The higher the Cold Cranking Amps (CCA), the more powerful a car battery will be for starting the engine in cold weather.
What Do Cold Cranking Amps Mean?
Cold Cranking Amps (CCA) measure your car battery’s ability to crank the engine in cold weather. It’s a very important rating because when you start your car on a cold day, there’s no time for your engine to warm up.
A higher CCA rating on your car battery means it will be more powerful for starting. The lower this number is, the less starting power it will have.
Also, the size of a car battery is important because it dictates how much power you need to get your vehicle started. A car with a larger engine and more accessories will need more starting power than one with a smaller engine and fewer accessories. The size of your battery can also depend on where you live because colder climates require more starting power due to the increased difficulty of starting engines in cold weather.
If you drive an electric car, your battery capacity is much larger, typically measured in kilowatt-hours (kWh) rather than amp-hours. The current draw can be very high during acceleration, potentially hundreds of amps.
For internal combustion engines, the amount of current an engine draws depends on the load. An engine running at idle will draw much less power than one at full throttle.
Here are some examples of typical alternator outputs for different types of vehicles:
Smaller cars and hybrids: 70-120 amps Medium-sized sedans and SUVs: 120-150 amps Bigger SUVs and trucks: 150-200 amps
These figures represent the maximum output of the alternator, not the constant current draw of the vehicle.
Conclusion
You now have a better idea of car battery capacity and Cold Cranking Amps. We should note that it’s possible to damage the battery by trying to draw more current than it can safely provide or by deeply discharging it repeatedly.
If you’re looking for something that goes into more detail on the subject, we suggest checking out resources on car battery specifications and their capacities from reputable automotive or battery manufacturer websites.