When starting a stock vehicle, almost any battery with the correct cranking amps and voltage can suffice. However, when said vehicle is expected to fulfill multiple roles — as the family hauler, race car tow pig, and recreational camping or overlanding home base — a basic battery falls short. The increased demands from video monitors, stereo systems, wrenches, refrigerators, and more call for a battery capable of deep cycling. Deep cycling is a term used to describe when a battery can be discharged significantly and then recharged to completely the cycle. While Optima Batteries is a familiar name among enthusiasts, the company’s batteries are distinguished by a color-coded product placement system indicating their specific applications that you may or may not know. We sat down with Jim McIlvaine at Optima to get the full rundown on which battery is best for deep cycling in automotive applications and the best way to charge them.

Optima Yellow Top Versus Red Top

Like all automotive batteries, they are initially classified into a group size, established by the Battery Council International (BCI) to indicate physical dimensions. We’ll assume you can locate the appropriate group size for your needs, enabling us to concentrate on the distinctions between battery designs and intended uses of the Optima Yellow Top and Red Top.

“The Yellow Top battery is designed and warrantied for both starting and deep cycling use, while the Red Top is specifically designed and warrantied for starting use,” McIlvaine explains. “If you’re planning to incorporate car audio, monitors, overlanding equipment, or any heavy electrical accessories, the Yellow Top is the better choice. Although the cranking amps of the Red Top are actually greater in the same group size as the Yellow Top, it’s not recommended for deep cycling.”

We chose the Optima Yellow Top for our full-size SUV. As a family of six who frequently tows and camps, it’s reassuring to know that our electronic systems will be well looked after.

While noting what might constitute a deep cycle application seems straightforward, it often exceeds what most people consider. “Car audio modifications, wrenches, plows, refrigerators, or even a car alarm should be considered to need a deep-cycle battery,” McIlvaine says. “Some alarm companies say it’s like having a 100-watt light on, but people leave the glove box open, and the small light drains the battery. A 100-watt light will quickly deplete a battery.”

Charging Forward

At this point, you’ve likely determined which battery best suits your needs. But how do you charge a unique battery such as Optima’s absorbed glass mat (AGM) line? The answer is surprisingly simple. McIlvaine explains, “Contrary to common belief, you don’t need a special battery charger for Optima batteries’ unique design; almost any battery charger will suffice.” However, you may encounter issues if you use a gel-specific battery charger or set a charger to ‘gel’ mode. Gel cell batteries use sulfuric acid mixed with fumed silica to create a gel-like substance, unlike AGM batteries, which have the battery acid absorbed into fiberglass mats. Unfortunately, a gel battery charger may not fully charge a regular Optima AGM Battery, potentially causing damage.

Recognizing the use of the deep cycle or regular charging setting leads to McIlvaine’s next technical point. “People often assume that a battery reading 12 volts is fully charged and ready to go, but in reality, it’s significantly discharged. The Yellow Top, for example, is fully charged at 13.0 to 13.2 volts, whereas the Red Top reaches full charge at 12.6 to 12.8 volts,” explains McIlvaine. “It’s crucial not to be misled into thinking that 11.8 volts is acceptable.”

While Optima says that traditional battery chargers set to AGM or lead acid can charge its Yellow Top battery, we chose the Optima Digital 1200 12-volt charger for its advanced features. This charger, featuring microprocessor controls, charges, conditions, and maintains 12V AGM and flooded batteries, while also offering additional benefits such as recovery of deeply discharged batteries, an LCD battery charging gauge, and quick set selections for easy operation.

Although an Optima-specific battery charger is not necessary, it does offer significant benefits. “Most returned batteries are usually just discharged; people don’t have a charger, or their battery is too discharged for their charger to deliver current because it thinks it’s a bad battery,” McIlvaine explains. “The Optima battery charger will work with batteries discharged to 1.25 volts, but for safety reasons, not any lower. After all, you don’t want to deliver current to a coat hanger.”

“AGM batteries are very efficient in their operation, especially with Optima’s line, which feature two long pure lead-tin plates wound into a spiral, as opposed to traditional lead-acid batteries that use stacks of thick lead plates suspended in acid,” explains McIlvaine. “AGM batteries accept current faster than traditional flooded lead-acid batteries and deliver current faster and for longer durations.”

Your first instincts might be to jump start a car with a discharged battery, and while this method is okay for temporary use, McIlvaine cautions not to over use this practice. If you do, your alternator will bear the brunt of recharging the battery and can quickly cause it to burn out. Think of jumper cables as the electric equivalent of a 1 gallon can of gas, its enough to get you to where you need to be, but once you arrive, consider putting a battery charger or tender on it.

Bigger Is Better

In modern vehicles, the available space for larger-than-factory batteries might be limited. However, in the case of tow vehicles or overlanding setups, space constraints under the hood are typically not an issue. McIlvaine suggests purchasing the largest battery that will fit. “The larger the battery, the longer it will last. In the same application, you won’t cycle it as deeply.”

If you find yourself immersed in the depths of a massive overlanding build or the ultimate race car hauler equipped with lighting, radio, power tools, and refrigerator, you might want to consider installing a secondary battery. By isolating the starting battery, you ensure a reliable ride home once the party’s over, while the alternator setup can then recharge the secondary battery.

What Is The Best Battery?

The best battery for your application will depend on what you want it to do. Whether you have two kids watching Bluey while you’re hot lapping at the drag strip, or you’re taking the family camping and need electricity for your remote campsite, the Optima Yellow Top makes a much stronger candidate than the Red Top. After all, they color-coded these for a reason.