What types of car batteries are there?
Graham Reynolds | 18th Aug 2023 | 7 minutes to read
Many people think of car batteries as one-size fits all, but there are actually major differences between batteries that mean they aren’t all interchangeable.
If you’re planning to perform a car battery replacement, putting the wrong battery in your car can not only cause major issues for your vehicle, it can also be dangerous, so understanding the different distinguishing features of these batteries is crucial.
With help from our friends at Mechanic.com.au, we’ll take a look at the different types of batteries on the market and what they are generally best suited for:
What Does a Car Battery Do?
It is often said that the battery is the main source of electrical power on any vehicle, but this is not correct. While the entire electrical system on a vehicle draws electrical power from the battery, the alternator is the primary source of electrical power.
The alternator replaces the battery’s “stock” of electrical energy as it is used up by all the systems that make the vehicle work. If the battery is in a good condition, it will supply sufficient electrical power to all the vehicles’ electrical systems.
It is important to mention that a faulty alternator can often masquerade as a faulty battery to the uninitiated, as the most common symptoms are that their car won’t start or a battery warning light appears on their dash.
Instead of taking their vehicle to a professional mechanic for proper investigation, many motorists will often go ahead and purchase a new battery, which at first, appears to solve their problem. Unfortunately, after a couple of days of driving, they find themselves back in the same scenario because the faulty alternator isn’t replenishing what the vehicle’s electrical systems are taking out.
How Many Types of Car Batteries Are There?
Also known as “LSI” batteries (Lights, Starting, Ignition), car batteries are different from the high-voltage battery packs that power hybrid and electric vehicles. Also, LSI batteries comprise a wide range of technologies, chemistries, and constructions to meet different power demands on different types of vehicles.
Batteries are also made in a wide range of sizes, capacities, and different terminal configurations to meet car manufacturers’ design specifications. Here are some details on the three main types of LSI batteries that are in common use today.
Built by Century batteries, the Repco range of vehicle batteries suit thousands of vehicles
Flooded Lead-Acid Batteries
“Flooded” means that the battery’s lead plates are all fully submerged in a mixture of distilled water and sulphuric acid. Flooded batteries produce electricity when the electrolyte reacts with the lead and other metals in the plates. Flooded lead-acid batteries are the most widely used type of battery today, although they are the least efficient of all common battery types.
Enhanced Flooded Lead-Acid Batteries
An enhanced flooded LSI battery is a car battery in which the plates are thicker than in a standard flooded LSI battery. The plates are also separated by porous insulators. Enhanced flooded car batteries also feature polyester sheets between the separators and the plates to improve contact between the plates and the electrolyte. These enhancements increase the useful life of an enhanced flooded battery and nearly double its efficiency when compared to a simple flooded battery.
Enhanced flooded batteries can also endure more charging cycles than a simple flooded battery, and they can be discharged more deeply. However, an enhanced flooded battery cannot be discharged completely without damaging the battery.
Because of their high efficiency and long service lives, enhanced flooded LSI batteries are used in vehicles with simple start-stop systems that operate automatically. Simple flooded batteries can sometimes be replaced by enhanced flooded batteries, but both types of batteries must have the same capacities and ratings.
AGM (Absorbent Glass Mat) Batteries
AGM batteries are designed to meet the high-power demands of high-end luxury vehicles that feature a large number of electrical systems and in-car tech.
However, unlike flooded batteries that use liquid electrolyte, the electrolyte in an AGM battery is contained within a woven mat of glass fibres. This is to ensure a large contact area between the lead plates and the electrolyte. This construction method translates into a vastly increased efficiency and power output as compared to even the most advanced flooded lead-acid batteries.
AGM batteries can withstand almost three times the number of charge/discharge cycles than even the most advanced enhanced flooded batteries can. Therefore, AGM batteries are typically used in vehicles with advanced stop-start systems, which are common in high-end luxury vehicles.
AGM or stop-start batteries are now commonplace as more vehicles share this technology
What Is a Gel Car Battery?
Although gel batteries are spill-proof like AGM batteries, the electrolyte in a gel battery is mixed with powdered silica (sand). This mixture has a thick, gel-like substance, hence the name “Gel” battery.
Gel batteries are more efficient than flooded batteries and compare favourably with AGM batteries in terms of power output and durability. However, the "jellified" electrolyte mass is extremely fragile. This means that the electrolyte mass can be easily damaged by vibration and high temperatures.
Also, gel batteries are very sensitive to overcharging, as well as quick and/or deep discharges. Therefore, gel batteries are extremely prone to premature failures, which makes them the least suitable battery for everyday use in cars and trucks.
What Is a Deep Cycle Car Battery?
Normal LSI car batteries are designed to deliver short bursts of high amperage current to start the car. Deep cycle batteries, on the other hand, are designed to deliver steady currents over longer periods. One example would be running loads over long periods such as might be found in a caravan or recreational vehicle.
Because deep cycle batteries have thicker plates than conventional LSI car batteries, deep cycle batteries can supply more power over longer periods than conventional batteries can. Therefore, unlike conventional batteries that usually do not discharge more than about 15% during normal use, deep cycle batteries can be run flat completely without suffering damage.
In practice, deep cycle batteries have about three times more RC (Reserve Capacity) than normal batteries, but only 50% to 75% of a normal battery’s CCA (Cold Cranking Amp) rating.
As the second battery in a dual battery setup, a Repco deep cycle battery is a great option
What Are Car Battery Size Groupings?
Size really does matter — especially when it comes to car batteries. Therefore, the BCI (Battery Council International) has developed a standard system to classify batteries into different size groupings. Essentially, size groupings are based on the physical dimensions, as well as on the CCA (Cold Cranking Amp) and RC (Reserve Capacity) rating of batteries.
This makes it important to know what the recommended size grouping for your particular vehicle is when selecting a car battery. Here are some examples of common size groupings-
- Group 75: Most General Motors vehicles
- Group 65: Large-bodied Ford vehicles
- Group 35: Most late model Honda, Nissan, and Toyota vehicles
- Group 34: Most Chrysler vehicles
- Group 34/78: Some Chrysler and General Motors vehicles
As mentioned previously, physical dimensions are only one defining characteristic of a particular battery size grouping. Other and perhaps more important aspects are the ratings and pole configurations of batteries within a size grouping. Therefore, fitting the wrong battery could mean the premature failure of the replacement battery. Fitting the wrong battery could also damage the charging system, starter motor, and other electrical components.
Battery specifications and sizes are critical to the function of your vehicle
Why Are Only Some Flooded Car Batteries Sealed?
Although some flooded car batteries appear to be sealed, they are in fact, not sealed airtight. The chemical processes that create electricity generate large amounts of gas, so unless a battery can vent some of the gas pressure, it will explode.
To prevent this, battery cells are fitted with pressure relief valves to vent excessive gas pressure. The valves also allow hydrogen and oxygen to be absorbed back into the electrolyte. This process is necessary to maintain the battery’s state of charge, but the process depends on a certain pressure within the cells being present.
Fitting pressure relief valves on a battery prevents the loss of electrolyte. This means you do not have to keep on topping up the electrolyte throughout the battery’s useful service life.
Repco Has You Covered for Batteries
Repco’s battery range covers deep cycle batteries, stop-start, 4x4 & SUV batteries, as well as batteries for lawn and garden equipment and marine applications. If you’re in need of a replacement car battery, then you can use our online Rego Search to make sure you get the correct fitment or head into your nearest Repco store to receive help from our friendly staff.
