When your old OEM battery gives way, you may not be a to find an exact replacement, one with the same CCA rating or battery capacity (Ah) as the OEM battery.
Therefore knowing how fitting a battery with a higher or lower CCA or Ah rating affects the car alternator is useful to make the right buying decisions and saves you a lot of time and frustration.
So, in this post, I discuss whether fitting a large capacity battery CCA, Ah rating or a different battery group is bad for your car.
Quick answer: When fitting a new battery, aim to get one with the same or high CCA rating. The CCA rating basically determines how well the car battery performs in cold weather.
So, in essence, a higher rating handles extreme cold weather better than one with a lower one.
What’s the Danger in fitting a Battery with a Higher CCA rating than the Original?
You can use a battery with a higher CCA rating than the original. The CCA rating is an indication of how many amps the battery can deliver in extreme weather at 0° F for 30 seconds before the battery voltage drops to 7.2V or 1.2V per cell.
So in essence a batter with a higher CCA rating battery handles car starts during extremely cold weather better than one with a lower CCA raring.
What CCA size should you Select for the Car Battery?
Aim for an exact or slightly higher capacity (CCA rating ) as a replacement. Check the battery specifications imprinted on the original OEM battery for the battery specifications.
Note, that it is common for new batteries to read a higher CCA than is indicated on the battery.
How CCA is Calculated?
The general rule of thumb is for every cubic inch (0.016 liters) of engine displacement for petrol and two for diesel engines.
So, the larger the engine (liters), the higher the CCA should be.
Consult your vehicle’s manual for recommended CCA rating.
This can be particularly useful if you’re using a stock battery.
Is Bad to fit a Battery with a lower CCA battery than the Original?
No, this is not advisable to use a battery with a lower CCA rating more so if the car is used in very cold weather.
Doing so increases the likelihood of the car failing to start during extreme weather and as the battery ages.
The risks of Fitting a Battery with a Lower CCA rating
When a battery with a small CCA is fitted into the car, in cold weather, and as the battery ages, there is a higher likelihood of the battery failing to start the car compared to using a battery with a higher CCA. As the battery ages, its CCA reduces.
Related posts: What can damage the car’s alternator?
Is it Bad to Fit a Battery with a Different Battery Group than The Original?
Battery groups help identify batteries according to their physical sizes and terminal locations.
So, you can buy another manufacturer’s battery with confidence that it will fit in your car as long it has the battery group specified for your car model.
To know what battery group to use, you can check the car owner manual for the recommended battery group size or the battery group inscription on the battery being replaced.
Does Fitting a Battery with a Larger Capacity (Ah) Pose a Problem for the Car?
Not necessarily, much as you should aim to fit a battery with the same capacity as the original OEM battery sometimes it is not possible because the desired capacity is not available.
So, it is advisable to err on the side of using a battery with a high capacity (Ah).
A larger capacity Ah or C20 rate provides more runtime for the car’s accessories and electrical system when running on battery.
The battery capacity C20 rate (Ah) is a measure of how much energy is stored in the car battery(Ah).
It gives you an indication of how much energy the battery can deliver continuously for 20 hours at 80° F before the voltage drops to 10.5V.
The Problem with Fitting a Battery with a Lower than Recommended Battery Capacity (Ah)
Using a battery with a lower capacity (Ah) reduces the runtime or reserve capacity of the battery compared to the original battery.
This can also affect the battery’s lifespan faster, for example, if you make repeated attempts to start from it because of the lower available capacity.
Final Word
Fitting a larger capacity battery capacity (Ah), CCA does not damage the car’s alternator or electrical system.
If fact it is generally advisable to use a battery with a slightly higher Ah or CCA rating if that is what is available.
Using a battery with a different battery group than specified in the owner manual may result in a return of the different physical dimensions of the available mounting space or may require that your purchase cable extensions for example make up for shortages in battery cable length because of the different battery post locations.
So, always aim to get a battery of the same battery group as the original or specified in the car owner’s manual.
