Car batteries are found in virtually every gas or diesel vehicle. They provide power to start the car and power to run accessories from everything from power windows to auto driving electronics in today’s modern vehicles.
An average car battery can provide up to 1 amp for 48 hours, 2 amps for 24 hours, 4 amps for 12 hours, 8 amps for 6 hours, and so on. Their most challenging function is to provide sufficient power to crank the engine in all types of environments.
Extremely cold weather, as well as hot weather, can severely damage and lower the power capacity of the battery regardless of the electrical storage capacity. This is the requirement for the standard 12volt car battery.
It should be noted that the type of battery discussed in this post is the traditional 12v car battery found in gas or diesel vehicles. Keep reading to understand how many amps does a car battery have.
What are amp ratings?
Several different amp ratings tell us how good or powerful a battery is and how well it will provide power in various situations.
CCA – Cold Cranking Amps is a car measure of how much power a battery can provide over 30 seconds at an ambient temperature of zero degrees F. this measurement is particularly important if you live in cold temperatures that make starting engines difficult.
CA – Cranking Amps is a car measure of the battery’s capacity. CA is the value of current the car battery can provide for 30 seconds at 32 degrees Fahrenheit, and the voltage stays above 7.2 volts.
RV – Reserve capacity is a measure of how long a battery can be discharged at a rate of 25 amps and measured at an average temperature of 80 F. if a car battery has a rating of 120, it means that the battery can provide 25 amps for 120 minutes.
How do ampere ratings work?
Consumers purchasing a new battery should follow the manufacture’s recommendations for their vehicle. However, if you live in a cold climate or have added various electronics to your vehicle, a more powerful battery may be needed.
CCA is important since this measures the Cold Cranking Ampere. A higher-rated battery may be needed in cold climates when starting a car engine. The car battery must provide power to the starter to crank the engine while at the same time providing power to all of the car’s systems, including the computer, ignition, fuel pump, dash lights, and much more.
RV – if you like to run video or music systems with the car engine off, pay attention to reserve capacity. A higher value means you can run these systems longer before draining the car battery and not being able to restart your vehicle.
CA – if you do not live in areas that have cold temperatures, you may want to pay closer attention to CA since this measurement is taken 32F and measure car battery amps provided for 30 seconds with the voltage remaining above 7.2 Volts
How many car battery amps are in a 12-volt car battery?
CCA, CA, and RV are measures of how much power a battery has under specified conditions, e.g., temperature and static amp delivery. It does not tell you how long the car battery will last without being recharged.
AH or ampere-hours measures or indicates how long a new battery that is fully charged can provide a specified number of amps. For example, a car battery with 48 AH can provide 4 amps over 24 hours. Using the same ratio, it could provide 2 amps for 48 hours. Many people refer to AH as the storage capacity of your battery to provide a specified current over time.
The larger an ah number, the more battery amperage it can provide over a longer time. AH is another important number to take into account when purchasing a battery, depending on the application. E.g., starting the car in cold weather, running the lights and electronics with the car engine off, trolling motors in marine situations, etc.
How many amps do car batteries produce?
The number of amps produced by a car battery depends on the design and the internal chemistry of the battery. Car batteries amperage ranges between 550 and 1000 amps, and the size of the battery for each vehicle is specified to meet the needs of the vehicle.
The voltage and the internal resistance of the battery determine the maximum amps that can be produced by the car battery performance from each battery cell.
However, cold crank amps are an important indicator since this is the number of ampere ratings provided by the battery that is available to start the engine in temperatures at 0F. This is a better indicator of the type and power of the battery needed for your vehicle.
Before purchasing a battery, check your owner’s manual for the specified battery type and amp ratings to ensure that you purchase a battery with appropriate CCA and CA ratings.
Car Battery Amp Hours Chart Explained
Amp-hour charts are useful to review when purchasing a battery. They tell you the rating capacity percentage at a given discharge rate over time. For example, a 100 AH rating indicates that the battery can provide 5 amps of power for 20 hours and will be 100% discharged.
The capacity of a battery is not linear. After 10 hours with a 5-amp power draw, it will be 90% depleted, even though it has provided only half of the power it is rated to provide. These measurements and power capacity levels are for batteries that are new and fully charged.
As they age, go through many charges and discharge cycles, their capacity declines. If you are relying on an older battery to provide amps for an extended period, such as a trolling motor in a boat, your expectations may need to be adjusted to something less than the specifications given.
Different Cranking Amperes Explained
The specifications do make a difference for many people depending on the application, the size of the motor, the environment, and the accessories you have in your vehicle.
Most can follow the specifications provided by the vehicle manufacturer. However, if your situation differs from the norm, you may want to take the time to understand CA, MCA, CCA, HCA, and PHCA. Technicians at your car battery supply store can also help select the right battery for your vehicle.
Cranking Amps (CA)
Cranking ampere or CA is the amount of current provided by a battery measured at 32F for 30 seconds at a voltage of 7.2 or above. This number is important since it indicates the power the battery can provide while cranking the vehicle and running all of the electronics until the engine starts.
Marine Cranking Amps (MCA)
Marine cranking ampere or MCA is a measure of the current a battery can provide at 32F. They are used on boats and garden equipment where the colder temperature variants are usually not a factor for many applications.
Cold Cranking Amps (CCA)
Cold Cranking Amperes or CCA is the current a battery can deliver at 0F for 30 seconds and maintaining a voltage of at least 7.2 volts. Modern cars are designed to start almost instantly and are not as reliant on CCA in cold temperatures. CCA is important with older vehicles and in severe cold environments.
Hot Cranking Amps (HCA)
Hot Cranking Ampere or HCA is the amount of current the battery can deliver at 80F for 30 seconds and maintain a battery voltage of at least 7.2 volts. If you are predominantly in a warm climate, drivers may want to pay attention to his measurement for their batter’s health and ability to deliver power at these temperatures.
Pulse Hot Cranking Amps (PHCA)
Pulse Hot Cranking Ampere or PHCA is a measurement assessing the maximum current a battery can deliver. The measurement is indicated in amps and seconds, e.g., 200 amps for ten seconds, etc. It applies to a new battery and is measured over 3 to 5 seconds at 80F.
How do you measure a car battery amp?
One of the simplest ways is to measure the voltage of the battery using a digital multimeter. A good battery should indicate 12.6 volts with the engine off and approximately 13 to 14 volts with the motor running.
At 12.6 volts, there is 100% of the capacity remaining in the battery. At 12.4 volts, there is only 75% and below 11.9 volts, which means the battery is pretty much dead as far as being able to provide sufficient cranking power.
Attach the red lead to the positive terminal and the black lead to the negative terminal of the battery to measure the voltage. If the meter goes negative, switch the leads. Multimeter battery testers should be set to read DC volts at the 20-volt level. Read the number of volts on the meter to assess the health of your battery.
How long does a car battery last?
The capacity of a battery does change as it ages and also how it is used. Modern batteries last between four to seven years. The huge variance in age longevity depends on how the battery is taken care of, and this, in turn, reduces the amp hours and amp rating.
Heat, vibration, deep discharges, and age affect longevity along with normal wear and tear. Batteries that experience deep discharges do not charge fully and often discharge easily compared to when it was new. In turn, crank amps and cold crank amp measurements will reflect a decline in the ability of the battery to meet original specs.
Another factor during discharges in weather below freezing places the battery in danger of freezing, potentially causing cracking of the case and support structures inside the battery. Replace a cracked battery immediately. It will not hold a charge.
What is the car battery reserve capacity RC?
There are three main categories in terms of ratings for a battery, Cold Cranking Amperes, Cranking Amperes, and Reserve Capacity. Reserve capacity measures how long a battery can be discharged at a standard rate of 25 amps.
RC is usually measured at a normal temperature of 80F, and the measurement is in minutes at the rate of 25 amps. If the discharge period is 130 minutes, it means that the battery can discharge at a rate of 25 amps for 130 minutes.
At this point, the battery typically would not have sufficient reserve remaining to start your vehicle. Reserve capacity is important if you plan to run accessories off the battery with the motor OFF and not charging the battery. Always ensure that you do not exceed this number.
Do car batteries charge while driving?
Once the vehicle starts, the alternator begins generating sufficient electrical power to recharge the battery and all of the lights, accessories, and other electrical components in your vehicle.
While driving, the engine’s RPM is sufficient to recharge the battery and provide power to all of these other components. Even a vehicle that is idling should generate sufficient power to recharge the battery. However, it may take more time to recharge the battery completely.
If you notice the lights dimming when the motor is idling, the battery may be failing, or the alternator may need to be checked. The check engine light may be illuminated, indicating that the battery or the alternator may need servicing.
Is it better to charge a battery at 2 amps or 10 amps?
It is generally accepted that slow charging a battery is better than fast charging. With that said, a 2 ampere rating battery charger will take longer to fully charge the battery but will leave it in better condition than a fast charge at 10 ampere ratings or higher. Lower amp ratings to charge a battery take longer but is better for the battery.
Repeated fast charging of a battery can sometimes lead to overcharging a battery which can reduce its performance significantly. A brand new battery has CCA, CA, and RV ratings to help drivers select the correct type for their vehicle and the environment the car is driven in. However, with repeated fast charging, these ratings are no longer valid and may cause starting and operating problems later on.
A fully discharged 48-amp hour battery will take 24 hours to fully recharge with a 2-amp hour charger. A 10-amp hour charger takes just under 5 hours to recharge the car battery. Circumstances and requirements often dictate which charger is used.
How many amps is enough to start the engine of a car?
Most small and mid-size engines can be started with a car battery capacity of 400 amp CCA rating. However, there are a variety of factors that may increase or even decrease the requirement. You may need to consider these elements if you are replacing a battery or using jump starters to start your engine after your engine failed to start.
- The viscosity of the oil
- Diesel or gasoline engines
- Motor condition and maintenance level
- Condition of the wiring and corrosion
- Age and condition
Most car batteries perform well during normal weather conditions. If you need to jump-start your engine, always connect a 12-volt source to the car battery and ensure that the proper connections are made. It is always good to have on hand a car battery charger in case you need quick charging.
The source must have sufficient CCA and CA ratings to properly start your engine. For example, if you are trying to start an engine that requires a 1000 amp rating, a 400 amp jumper is not going to be able to do the job. Most battery chargers nowadays are compact and can be simply hooked into the negative and positive battery terminal.
Average Car Battery Amperage Charging Time
Most batteries come in various capacities and types. Lead-acid batteries, deep cycle batteries, sealed and unsealed. All are 12 volts, but many different capacities different loads. When buying any given car battery, you need to check amps, ampere hour, electrical load, battery terminals, battery plates, and overall lifespan.
Small engines to large diesel-driven trucks, environment – cold vs. hot are among some of the variables to consider. Pay attention to CCA rating – Cold Cranking amperes, CA rating – cranking amperes, and RC – reserve capacity are the main specifications.
Review your car’s manual for the recommended car’s battery amps and specs and adjust if you add accessories or are driving in extreme environments. We recommend getting a jump starter in case you need to charge a car battery for either compact cars or even larger vehicles. Now you know how many amps you need to charge a car battery.