I bought a new car battery based on the CCA (cold cranking amps) values, and I didn’t quite understand relationships between Ah (Amp Hour) and cca, I thought it was the same thing, so I did a little research. So how many amp hours in a 600 CCA battery you might ask? I went back to the store and speak with the professionals there and I also look online to confirm answers I get from an experts.
Before I give you the answer let me ask you something. Do you have some dead batteries laying around your house? What if I told you that you can bring those batteries back to life again just with a few simple steps in comfort of your home like I did? I highly recommend you to read my experience on how I recondition my batteries. Now, get back to the cold cranking amps and amp hours.
The quick and short answer on this question is that it depends. While there is no direct correlation between CCA (cold crank amps) and Ah (Amp Hour) some companies tend to give their exact formulas on how they get this relations. But it’s not that simple. I saw some formulas such as this: 100 Ah x 7.25 = 725 CCA. So, as stated in this example formula if u have Ah number which is 100 Ah you simple multiply that number with a 7.25 and u will get CCA value. And I saw even this one: 600 CCA x 0.7 = 420 Ah. Which is opposite one. In this case for the given CCA value you multiply that number with a 0.7 and you will get Ah value. But that is only if certain companies gives that kind of information which is based on their battery design and development. And also the greater the cold cranking amps, the greater amp hours you will get in car batteries. There is no such thing like battery cca calculator in general for you to confidently calculate.
What is a cold cranking amps and why is it so important?
Cold Cranking Amps, or CCA for short is a number value which means how much the car battery is able to start car engine in cold temperatures. This number value refers to amps that 12 volt battery can deliver at 0°F for 30 seconds while keeping a voltage of at least 7.2 volts.
The name alone refers to cold climate, so to speak it is much harder to start car engine in colder climate then in warm climate. So, it is so important to keep in mind, if you are living in colder climate, of cca because this number is most important to you. The batteries with more cca power will give you more confidence as time passes.
And battery will give you lower cca power over time as they age. And you should always replace battery with the same cca specification or grater one. If you replace with the lower cca specs then is specify you will get bad performance.
Why I need to know about the amp hours (ah) of the car battery?
The Amp Hour number value is a number that tells the maximum battery energy capacity under ideal conditions. And determine how long will battery last under certain factory load (how much current will be drawn), and this number is expressed in Ah (Amp Hours).
Car battery capacity of 1 amp hour should be able to continuously deliver current of 1 amp to a load for 1 hour, 2 amps for half an hour and so on, before being completely discharged. This numbers are given by the factory of a car battery and it is really just a simple linear formula. Read this post in case you wonder how much amps are needed for the car to start.
For example if a battery have capacity of 80 amp hour, and it is specify at a current of 4 amps. This means that battery can last for 20 hours at 4 amps of load. And now let’s say that the load is 80 amps, in that case (80 amp hours / 80 amps) will give you total time that battery will last of 1 hour.
And even this will not be true, because with higher current battery will dissipate more heat all over the internal resistance, and it will negatively affect time battery can last under greater load.
How to calculate amp hours from reserve capacity?
Ampere-Hour (AH) or Reserve Capacity or Reserve Minutes are mostly tight correlate with deep cycle batteries. That term refers to rating of requirements and how much weight you can handle.
Majority of deep cycle batteries have 100h, 20h and 8h discharge rates. Internal resistance of the battery will determine how much the capacity and discharge will be. The higher the capacity, the lower the discharge.
Reserve Capacity is the value of minutes a fully charged battery at 26.7 o C is discharged at 25 amps before the voltage drops below 10.5 volts. To get Ampere-Hours at 25 amp, from converted Reserve Capacity, multiply RC by .4167.
All you need to know about Voltage (V) of the car battery
Volts or (V) is a measure of electrical pressure inside the battery, and it refers to volts direct current or volts (DC). Voltage can vary and it depends on a electrochemical reaction inside the battery. When you buy a new car battery it should be 12.7 volts at 21 Degrees fully charged.
If you live in colder climate this number should be slightly lower and opposite, if you live in warmer climate this number should be slightly higher. Readings should be taken without any load and some time allowing surface charge to be dissipate.
If you don’t follow this instructions you will get false readings. When time passes the temperature in the car battery also drops, so does the capacity of the car battery drops too. Also. check this article if you want to know more about what is the voltage in your car battery while driving.
When you start measure with the multimeter when starting engine and voltage drops to 9.6 volts or lower, this could be sign that battery getting weak and losing performance. This will be very inconvenient especially if you live in colder climates. If you encounter problem that battery won’t hold charge it may be the alternator problem.
You can also measure alternator current at cranking and it should give you anywhere from 13.79 volts to 14.20 volts. On some cars it can go as high as 15 volts. When you measure alternator voltage and it’s shows higher number it may be that Alternators voltage regulator is going bad.
Anyhow if it shows lower number it may be that the serpentine belt is worn, and it needs to be replace, or there is not enough tension on the belt so it can’t give enough rotation for the alternator to generate required charging voltage. If battery doesn’t take charge from alternator it might be just simple cleaning of the battery terminals.
How to tell if a car battery is bad?
This part will be helpful for anyone trying to decide if they need to replace their car battery. You will read about some common symptoms of a dead or failing car battery.
First of all you’ll need to look for some obvious problem before even decide anything, and make sure to check my article whether the magnets can damage the car batteries.
Check to see if battery is clamped down the way it should be, then check and make sure that both of the terminals are tightly secured.
Look up for terminal connections and make sure that they are not dirty or corroded, that my cause the charging wont work properly. If that’s the case clean terminal with the solution of baking soda and water.
Also if the top of the car battery is dirty you should clean that too, because dirt on the top of the battery can cause a parasitic drain. Check the age of the battery. Batteries can last anywhere from 3 to 7 years depending of the quality and the conditions in which the car is driven in.
If you’re buying a used car, please check under the hood if clamps are are connected correctly to the battery terminals, because if they are loosely connected you must know whether the car can run without a battery once it starts.
If you hear a squealing belt that is an indicator that a belt is loose, so you must tighten the belt. Also see if the belt is worn and replace it. If it’s worn out it will be slipping and wont charge properly. One of the indicator is that car is cranking but wont start. The chances are that starter is bad, or may be something else.
To see if the car battery is bad jumpstart the car and let it run for 30 to 40 minutes to recharge the battery. Then turn it off, wait for several minutes and restart it. Repeat starting 2 more times and if it fails again then you will probably need a new car battery.
If your battery just sits, for too long and without a charge once in a while it’s 99% dead. Read here to see what happens to the lead-acid car battery that has not been used over time.
Check in the auto-parts store with their battery load tester and verify if battery is bad or not. If it’s bad it’s obvious you should replace it. Another symptom of dead battery is if the car won’t start and headlights won’t come on, there is a good chance that battery is dead.
Go to your mechanic or the local mechanic store to load check the battery. If the battery is good then you should visit your professional mechanic to check your car, or what you certainly must do is to check my best maintenance tips for car batteries.
How should I choose a new car battery for my vehicle?
Unfortunately car batteries eventually goes bad. So choosing one by your own could be so frustrating process. And before you read about how to choose a new one, read my article of how to prolong the service life of a car battery.
Let’s hear some history first. Back in a days car batteries didn’t come with the acid pre-filled. Batteries was naked and vacuum sealed.
So when you buy one, before installing it in a car you’ve break the seal and fill it up with acid before use. That kind of batteries have indefinite shelf lifespan.
This days they already come with acid factory filled in. And they start to deteriorate the minute they put acid inside. So always check the date of manufacture before buying the battery. Some of them come with the removable top and some come with sealed top.
If you choose with the removable top you could add up distilled water over time and expand battery life that way.
With the sealed one you can only buy a new one as a replacement. So choose wisely. But that’s not all, if you are kind of person that will never check the battery water buy sealed battery exclusively.
Of course they are not sealed perfectly, they have smaller vents to vent a gas, and they lose water but a lot slower than a non sealed one. There are other factors too. It has to be 12 volt battery for sure but how many CCA and how many Ah it depends on your car battery specifications.
If you want to know how many amp hours in a 600 cca battery, please read this article from the beginning. And also a battery size, cause they are not all the same dimensions.
What is alternator and how it works?
An alternator is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. Electricity is produced in alternators by electromagnetic induction. There are two types to produce electricity in alternators:
- Rotating magnetic field with a stationary armature and
- A rotating armature with a stationary magnetic field
Most alternators uses rotation magnetic field with a stationary armature. Main parts of the alternator are:
- Outer Cover,
- Slip Ring and
- DC Generator.
Rotor produces a rotating magnetic field, armature and coils are stationary and rotating magnetic flux associated with the rotor induces electricity in the armature coils. For better understanding let’s consider a rotor with just four poles. Rotor coils are excited with a DC power source, magnetic field are produced around.
The rotor is made to rotate using the shaft, this makes the rotor flux also rotate along with it at the same speed, such revolving magnetic flux now intersect the armature coils which is fitted around the rotor, this will generate an alternating EMF across the winding since four polar rotor has got two pairs of NS pole.
When the rotor turns a half revolution the induced EMF takes one complete cycle, so it is clear that frequency of the induced EMF is directly proportional to the number of poles and rotor speed, it can be easily established that frequency of induced EMF, rotor speed and number of poles are connected through the following relationship:
f(Hz), N(rpm), P
It is clear from this relationship that frequency of electricity produced a synchronized with mechanical rotational speed for producing three-phase AC current to more such harmony coils which are an 120 degree phase difference with the first is put in a state of winding.
Generally one end of these three coils are star connected and three-phase electricity is drawn from the other ends. Neutral cable can be drawn from the star connected end from the equation above, in order to produce 60 Hertz electricity.
A four pole rotor should run at following speed of 1800 rpm. Such huge rpm will induce a tremendous centrifugal force on poles of the rotor and it may fail mechanically over time, so salient pole rotors are generally having 1040 poles which demands lower rpm or salient pole rotors are used when the prime mover rotates at relatively lower speed 120 to 400 rpm, such water turbine and Dick’s engines.
DC current is supplied to rotor via a pair of slip rings, this is the reason why rotating magnetic field approach is used in alternator. If rotating coil method were used slip rings have to fit it along with the armature coils in order to collect electricity but transferring such high voltage electricity via slip ring is rather impractical.
It is quite possible to transfer low voltage DC excitation current via slip rings, this DC current is supplied either from an external source or from a small DC generator which is fitted on the same prime mover. Such alternators are called self excited.