How many Amps is a Car Battery?

A person should have knowledge about the various component of the car so that in case they have any problem they can deal with it easily. So this article will guide you about one of the main components of the car which is the battery the car. The below information will explain to you how many amps is s car battery, the specification of the battery, how to measure the battery amps of a car, and What is an Amp-Hour Chart a Car Battery.

How many Amps is a Car Battery?

Most people only know about the volt a battery belongs to which is 12 volts but nobody knows about the ampere a battery draws to run a car.

A battery with an average of 12 volts is able to draw the amount of 48 amps-hours to run a car effectively. 

Car Battery
Car Battery

But there are many other factors that provide more power to a car such as the age of the battery and the condition. As when we compare a brand new car or a car with an older battery then the older battery of a car will have less capacity to hold the charge. The battery of a car that provides an amps hours rating is not only the rating by which you can determine how much power it can provide, there are many other ratings. There is a difference between the amps used by a car while running and to start of a car.

What is an ampere hour of a car battery?

Ampere hour. Amount of the energy charged in the battery of the car by which it enables 1 ampere of current which flows for 1 hour. In simple words, we can say that ampere hour is the rating that shows the capacity of the battery of how much amperage it can provide for one hour. The Abbreviation of ampere-hour is AH. The vehicles which have larger batteries are rated in ampere-hours but the standard batteries which are used in the devices test personal vaporizers, notebook computers,  etc those AA and AAA battery the rating are provided in milliampere hours.

Milliampere hour:

It also refers to how much print a battery of a car discharges over a period of time that is 1 hour. 

1 mAh is 1000th of 1 aH

A device that has a higher Milliampere value refers to either the battery of the device having a long run time or having higher storage capacity.

What is meant by the ampere rating of a car battery? 

Ampere rating is the rating that shows the maximum amount of current a battery is able to provide for a short period without any damage or disturbance. The ampere rating of a car is also called cranking amps or CA rating. The rating can be seen on the battery and it is higher than the amp hour rating.

An ampere Is the rate of current that flows in a form of an electrical conductor. In physical terms, 1 ampere of current defines or represents 1 coulomb of an electrical charge that is moving fast from a specific point in 1 second. And in more simple terms we can say that one ampere of a current is flowing for one hour. 

Car Battery
Car Battery

Mathematical representation,

Amp hour Ah = current I * discharge time T. 

Let’s understand by an example, Suppose a battery of a car draws 35 amps which are discharged in 40 minutes than 

Here current = 35 A, the discharge time = 40 mins (0.6 hours) 

Ampere hour = 35*0.06 = 21 Ah for 1 hour.

For example, if a CA rating of a car is 800 then the amp hour rating will be around 70.

The difference between the amp hour rating and ampere rating of a car battery:

An ampere rating of a car battery is the ability of the battery to provide power for a short period of time. And the amp hour rating is used to measure the capacity of a car’s battery for storing power over time.

There are various battery specifications on which the CA rating or amp hour rating depends such as:

  • Amp hour
  • Cold-cranking amps
  • Reserve capacity
  • Chemistry
  • Voltage

Amp hour:

It is the most common rating in order to check the power of a car battery. Amp hour rating does measure the ability of a battery to store power over time. The rating of amp hour is visible or printed on the battery of the car itself. A battery of a car that is showing a higher AH rating does have a longer battery which is able to power the battery. For example, a battery of a car has a rating of 100 AH and that is able to provide a current of 0.50 amps for 200 hours in more simple words we can say that it is able to provide a current of 20 amps for 5 hours.

Cold cranking amps:

The cold cranking amps show the measurement of the amount of current a battery of a car can deliver for 30 seconds at 0 degrees Fahrenheit. It is the amount of rating showing how well a battery is able to perform in cold weather. If a person is living in a cold winter area then having the highest CCA rating will help the car to start easily in cold temperatures than a battery having a lower CCA rating. On average a battery of 12 volts has a CCA rating of around 800. But the larger vehicles do have CCA rating which ranges from 700 to 1000 such as SUVs and trucks. 

Reserve capacity:

A reserve capacity rating of the battery of a car shows the amount of time a car can provide power at 25 amps. This is the power when the battery needs to be recharged again and the Reserve capacity shows the time the car can be used at that time. As with the reserve capacity rating a person can have an estimate of how long a fully charged battery will last. On average a reserve capacity of a car with a 12-volt battery ranges from 100 to 120.


Chemistry refers to the material which is used in composing the battery. the most common material which is used in car batteries are lead-acid and absorbed glass mats.

When we compare the lead acid of a battery they are the most common type found in the car and it is the least expensive and has a shorter life compared to the absorbed glass mat of a car’s battery. And the absorbed glass mat (AGM) batteries are the most expensive as they are made up of glass mats that easily get soaked in acid and tightly rolled and they do have a longer life span. 


Voltage in a car battery shows the amount of electrical pressure in a circuit which means that the amount of force the battery pushes is electron through a conductor. On average a standard voltage of a car battery is 12 volts but it may be higher in some high-performance vehicles which have 24v electrical systems.

Car Battery
Car Battery

List of lead acid batteries:

The following table shows the list of 12-volt sealed lead acid batteries which explains the terminal, voltage, ampere, length, width, height, Lbs, and price:

 Modelsterminal voltage amps  length width height lbs cost 
Set of 2
Set of 8
Set of 16
Set of 2
Set of 8
Set of 2
Set of 4
Set of 2
Set of 2
Set of 2
Set of 2
Set of 2
Set of 2

How to measure the amps of the car battery? 

We can easily major the amps of a battery by using a battery tester or a digital multimeter to measure it. If a person is using a multimeter then they need to measure the voltage of the battery. Then they need to know the ohm rating of a battery to measure the amps using Ohm’s law we can easily find the ampere by dividing the voltage of the battery by the Ohm rating which is measured by the car

The following table shows the reading of a multimeter voltage and the percentage of charge remaining in it.

Multimeter Reading(Volt)Percentage of Charge Remaining
11.9 and belowDead


A person should know all of this information so that they can ensure that they do not overcharge the battery and damage it. By the above-mentioned specification, they can easily calculate the amps of a car battery and the time they need to charge a battery fully. 


What ampere should we charge the battery of a car 2 amps or 10 amps?

use 10 amperes on a car battery and use 2 amperes on a smaller battery such as a motorbike etc.

Rick Costa

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