What Is Reserve Capacity On A Car Battery?

Buying a car battery is one of a hell of a task. You must ensure that you end up with the right battery, and that meets your expectations. Apart from choosing the right brand and a price that matches your budget, there are many other things that you have got to put into consideration.

The battery specifications in this case are relevant as they are what determine if a specific battery is worth the investment or not. One thing that you ought to consider and that can affect your buying decision is the reserve capacity of the cell.

So, what is reserve capacity, and what does it has to do with the battery of your car? As its name suggests, a battery’s reserve capacity can be described as the number of minutes that a fully charged (12 volt) battery can 25 amps at 10.5 volts when the temperature is 80 degrees Fahrenheit.

It’s one vital specification that is usually ascribed on the battery of your vehicle. You will encounter this term when dealing with a 12-volt battery.

Why Is the Reserve Capacity Important to the Battery Owner?

By now, you understand how your vehicle operates. You don’t necessarily need to know the details, but at least you can tell why the car needs a battery. Apart from powering the electronics and your headlights, the battery is what provides the starting power. It’s for this reason that the engine can’t turn over whenever you have a faulty battery.

So, what happens when you insert your key in the ignition knob and turn it on? A lot of things happen here. But, the most important thing is to know how the engine gets to roar. When the ignition is turned on, your fully charged battery pumps about 25 amps at 10.5 volts to the engine. This is the charge needed to power the alternator.

Once the alternator is powered, it takes control of the engine. From that point, the alternator continues to provide the juice needed to keep your car on the road. The battery, on the other end, is left idle, probably powering any electronics that you may have turned. However, the alternator still drives some charge into the battery while you’re on the road. It’s for this reason that you rarely need to charge your car battery manually.

What if the alternator malfunctions? Does it mean that your car can’t run? Well, you must know that alternators are not supernatural. They are components like the others. On some occasions, they are likely to break down. What this means to your car is that they won’t be able to power the engine or top up the battery.

However, this doesn’t mean that you get stranded. You can use the power from the battery to push on with your journey. It’s at this point that the reserve capacity comes in handy. You will need to estimate how long the battery can give steady power to your battery until it’s empty.

The measure of reserve capacity can efficiently deal with those kinds of estimations. Besides, there are times you wish to listen to the radio in your car while the car is off. With the reserve capacity in mind, you can easily estimate how long you should turn on the radio without draining its charge.

Related Article: Does Listening To The Radio Drain Car Battery?

In the recent past, cars are coming equipped with high-end accessories, and that means more power is needed. Many drivers have responded by installing secondary batteries in their vehicles. When installing these auxiliary batteries, you must consider their reserve capacity. This specification can help you determine the type of cell you should connect based on the amount of power that your power needs to run.

Reserve Capacity Vs. Cold Cranking Amps (CCA)

When it comes to picking the right battery for your car, another specification that you ought to consider is the cold cranking amps. If you live in the northern region, especially, you can’t ignore this region. CCA and the reserve capacity of your battery are two different things, and that can confuse you a lot.

People in the warmer regions don’t consider the cold-cranking amps at all. They choose the reserve capacity. The difference between the two terms is that the requirements are based on climate and temperature.

For instance, the cold cranking amps are the discharge that your car battery can give for half a minute while maintaining a voltage higher than 7.2 volts zero degrees Fahrenheit. Therefore, when it comes to the colder regions, the higher the CCA, the more quickly your car is likely to start.

Amp Hours Vs. Reserve Capacity

Another specification that can see you get confused is your batteries Amp Hours. They both revolve around what your battery can give. However, you have to know that they are two different things. For instance, when defining the two, reserve capacity answers the question ‘given a particular current load, how long will a fully charged battery last?’

When it comes to defining the Amp Hours of your battery, it answers the question, ‘what is the optimum current flows that can be produced by the battery steadily and still provide 20 hours of service?’ That’s how different the two specifications are. Each of them defines a unique quality of your battery.

How Can You Measure the Reserve Capacity of the Battery?

As stated earlier, the reserve capacity of your battery is usually indicated on the sticker found on the cell’s top or side. However, the stated figure often shows the amount of reserve capacity of a fully charged battery. So, what if you want to measure the ability of a cell that isn’t full?

Recently, technology has brought with it an advanced tool, Cadex CA-12, and that you can use to figure out the reserve capacity of your battery. The same mechanism can be used to measure the cold cranking amps of the cell, as well as the stage of charge, which are also essential.