The motor vehicle battery is responsible for two major jobs – starting the engine and powering your other electrical gadgets and gizmos. This includes everything from your radio to the wipers and any aftermarket additions.
Inside your car battery are cells that contain lead dioxide and lead plates submerged in sulfuric acid, creating ions and electricity. The alternator recharges your battery as you drive and supplies electricity to your electrical equipments.
Battery Voltage
The battery is the powerhouse of a vehicle’s electrical system. Understanding and keeping track of its voltage is vital to maintaining a smooth and functional drive.
A resting voltage of 12.2 to 12.6 volts is typical for a car battery. This indicates that the battery has a sufficient amount of energy to start the engine. However, it gets drained over time, especially if left unrun for several weeks. To avoid this, a trickle charger that plugs into household current is recommended.
Using a multimeter set to the DC (direct current) setting, connect one probe to the positive terminal of the battery and the other to the negative terminal. Be sure to remove any surface charge on the battery before testing. This is usually done by shining a flashlight on the case for a couple of minutes before attempting a reading.
Cold Cranking Amps (CCA)
CCA, sometimes called CC or CA in battery marketing terms, is a common metric for measuring the power capacity of automotive batteries. However, it shouldn’t be the sole factor driving your vehicle battery purchase decisions. You should also consider other important ratings like peak current, amp-hour (Ah) and battery reserve capacity.
In the battery industry, CCA is a measure of the amount of current a fully charged 12V battery can deliver for 30 seconds while maintaining a voltage of 7.2V at 0degF. This is a crucial rating for reliable engine starting in cold climates.
You can determine the CCA rating of your battery by using a multimeter capable of measuring high currents. Make sure the battery is disconnected from any power source and connect the multimeter to the terminals, observing the correct polarity. Once the meter is connected, slowly crank the engine while monitoring the readings. The meter will indicate when the battery is reaching its limits.
Reserve Capacity (RCC)
If you ask people what to look for when buying car batteries, they might suggest looking for the lowest price, a long warranty or a battery with the highest cold cranking amps. But rarely do they mention that reserve capacity is also an important metric to consider.
RC is the number of minutes a battery can sustain a 25-amp draw before its voltage drops below 10.5 volts in an emergency. This is a great indicator of the battery’s ability to power electrical accessories with the engine off.
Batteries are grouped into categories, or groups, based on their case size and terminal position. Each group has a two-digit code that identifies its physical dimensions. This helps to ensure that batteries of the same group physically interchange. Moreover, most of these batteries have a date code, a string of numbers or letters that indicates the month in which it was made. This information is usually stamped on the battery.
Battery Life
The battery’s lifespan is dependent on a number of factors. Frequent short trips can prevent the battery from fully charging, causing it to sulfate and reduce its capacity and lifespan. In contrast, consistent longer drives allow the battery to charge more thoroughly and promote a healthier life.
For this reason, if your car is frequently left unused for extended periods of time, it’s recommended to keep a trickle charger or battery conditioner in the vehicle to help maintain its life and prevent overcharging. It’s also important to avoid leaving your battery in a discharged state, as this can significantly shorten its lifespan.
To ensure that your battery is not fully discharged, it’s best to have the battery tested at least once a year. Often, this can be done during an oil change. If the battery tests low, having it replaced can help to prevent a dead start at an inconvenient time. However, even with proper care, batteries have a limited lifespan and will eventually die.