Car batteries supply electricity to keep your car’s accessories running and starts the engine when you turn on the ignition. It also helps stabilize voltage spikes when the alternator is working too hard.
Inside a battery are rows of cells that have lead dioxide and lead plates submerged in sulfuric acid. A chemical reaction between the plates produces ions that creates electricity.
Type of Battery
The type of battery used in a motor vehicle varies. Some batteries are designed for power generation while others are designed for engine cranking. It is important to understand the different battery types so that you can select and stock the correct ones for your customers’ vehicles and needs.
The most common battery is the lead-acid SLI battery (Starting – Lighting – Ignition). It uses a chemical reaction to produce the electric current needed to start your car’s engine and powers the lights and accessories after it is started.
Other battery types include flooded, gel cell and absorbent glass mat (AGM) batteries. Gel cells use a thicker electrolyte solution that is less likely to spill if the battery is accidentally knocked over. They also have a longer cycle life and are more resistant to vibration and shock than flooded batteries. Li-ion batteries are growing in popularity for their high power density and ability to hold a charge for long periods of time.
Terminals
Battery terminals are the conductive contacts that connect battery cables to your vehicle’s power source. They are essential for ensuring that electrical current flows smoothly between the battery and the rest of your car’s electrical system. The best battery terminals for your vehicle are made from a corrosion-resistant material and feature a design that allows for easy connection and disconnection of the battery cables.
Lead is the most common terminal material, though some are made of brass or zinc. Zinc terminals offer the advantage of being protected from corrosion by a layer of zinc, which helps protect them from moisture and humidity.
There are also specialty terminals like marine terminals, which are designed to withstand high humidity and saltwater. They feature a wing nut or stud design, which makes them easier to connect and disconnect. There are also side post terminals, which are found in some GM vehicles and are a space-saving alternative to traditional top post terminals.
CCA (Cold Cranking Amps) Rating
CCA is the measure of a battery’s power for cranking your engine. A higher CCA rating means a stronger, more powerful battery. It’s important to balance CCA with your vehicle’s size and needs. Always consult your vehicle’s manufacturer, our battery finder or a trusted auto pro to ensure you select a replacement with the correct CCA for your car.
CCA is especially important for people who live in cold climates. Cold temperatures slow down the chemical reactions inside batteries, resulting in weaker electric currents. Additionally, low temperatures cause engine oil to thicken and create more resistance during startup. A higher CCA rating compensates for these challenges and ensures your vehicle’s engine will start reliably despite the weather conditions. In general, a gasoline engine will need one CCA per cubic inch of engine displacement and diesel engines require twice as many CCAs. Lithium batteries offer exceptional starting capabilities even in the most extreme temperature ranges, while also offering long lifespans and shorter charge times.
Group Size
Historically there were many different car battery sizes in use, but when the Battery Council International created group size designations to standardize battery physical dimensions and power demands it became much easier to choose the correct battery for your vehicle. Of course, as with everything automotive, the battery industry likes to complicate things and you may see the exact same battery referred to by two different names. For example, a BCI “Group 48” battery may be called an H6 by European manufacturers.
With modern vehicles cramming more and more technology into tighter spaces getting the right size is vital to ensure that the battery fits securely and has adequate power capacity. A quick glance at a BCI group size chart or your owner’s manual can help you determine which battery is best for your vehicle. Once you know which BCI Group Size you’re looking for, you can then start to focus on other specifics such as terminal type and polarity, cold cranking amps, and lead-acid design.