Hot rodders have always paid close attention to auto-related technical developments and that includes Optima batteries in both Redtop and Yellowtop varieties. Typically out of sight and out of mind, a car battery isn’t the kind of thing average folks think about too much, but when problems arise a car battery can become the biggest roadblock of your day. When that happens, the battery comes to the forefront and you’re suddenly faced with having to make an expensive choice. That’s when having a knuckle-dragging hot rodder at your elbow might just benefit you, and it’s likely a hot rodder is going to tell you to check out an Optima battery. The big question is, should you get a Redtop or a Yellowtop? We’re going to answer that, but first some important background on lead-acid battery technology that makes either a potential choice.
These days, virtually every automotive battery manufacturer makes some type of absorbed glass mat (AGM) battery, a technology that is rapidly replacing the flooded electrolyte batteries most folks are familiar with. This technology replaces the liquid acid electrolyte with a glass mat embedded with a paste electrolyte that allows a denser arrangement of plates or, in the case of both the Redtop and the Yellowtop Optima battery, the windings of a spiral cell. Besides having a higher energy density, AGM batteries can be mounted in any orientation including upside down because there’s no danger of spilling the electrolyte or accidentally bridging the charge plates and creating an internal short. This makes them physically robust and able to take a lot of punishment.
Hot rodders are familiar with Redtop and Yellowtop Optima batteries because Optima has been working with gearheads on the battery and charging issues faced by racers a lot longer than anybody else. Failure due to vibration, physical damage, electrolyte depletion/sulfation, and continuous deep cycling made Optima a popular choice despite its higher price. Racers often run without an alternator, choosing to charge up between rounds or heats. Between these episodes, batteries are stored for long periods and ignored for months on end. If you’re wondering if a Redtop or a Yellowtop is best for you, this is the kind of real-world experience you need to draw on.
What We’ve Learned So Far
Over the years, we’ve promoted various batteries besides the Optima. We get it. Everybody wants to build a better mousetrap and our hat is off to any company that leads the charge to make cars better. In regards to the many AGM plate-style batteries that have popped up since the Optima came out, this author has tried a couple of these, the Odyssey Extreme and the O’Reilly Autoparts Super Start Platinum AGM, with the expectation that they would perform about equally to the spiral-cell Optima—a tall order. We’re not pulling any punches here: Both failed within three years despite commanding a premium price for the AGM technology, and in the case of the Odyssey, the battery had even been placed on a trickle charger designed for AGM batteries.
Why did they fail? It’s just an educated guess, but the biggest and most obvious difference between these batteries and the Optima is the spiral-cell arrangement. Even though the Optima’s spiral cells take up as much as 15 percent more volume than a flat-cell battery of the same cold-cranking amperage (giving plate-based AGM batteries a theoretical advantage), the spiral-cell container of the Optima case seems to do a better job of holding the plates tightly together and maintaining that integrity over time. Observation: There’s less edge length available for out-gassing of hydrogen sulfide with spiral cells, and intuitively, spiral plates resist swelling better than stacked plates. That’s just a guess based on hard-won experience, but feel free to duplicate our results. We gave other AGM batteries a shot, they failed, so now this author is a fan of the Optima, barring any future technology breakthroughs. With that disclosure in mind, your results may vary.
The Optima Redtop Battery
The Optima Redtop is what the battery industry calls an SLI battery, for starting, lighting, and ignition. SLI batteries are by far the most common type of OE battery, and they are designed to maintain a charge that’s near full and that seldom reach a discharge state greater than about 3 percent. Beyond that amount of discharge, the battery begins to break down chemically in a process called sulfation, in which lead sulfate crystals form and the battery’s capacity deteriorates. Fortunately, most cars never find themselves putting that kind of demand on a battery because they’re constantly being charged by the car’s alternator and only demand battery power for short, occasional bursts like starting a high-compression V-8 engine.
Those looking to replace a battery in a daily driver or commuter car will want to check out the Optima Redtop, the company’s primary SLI offering. That’s the model this author selected for a 1968 Plymouth Valiant with a high-compression 500ci big-block Chrysler. This car is ordinarily stored for long periods of time on a trickle charger, but it also sees long weekends at the drag strip, or car shows with long road trips on either end. Hot rods like this are generally the worst clients for any kind of standard SLI battery, AGM or otherwise, because they are often subjected to discharge levels greater than 3 percent simply based on being driven so seldom. The Optima Redtop can take a lot of this type of neglect—the silent, evil twin of abuse. Nevertheless, even an Optima Redtop may not be the right choice for your car.
The Optima Yellowtop Battery
Originally, Optima only offered the Redtop, but began offering Yellowtop batteries when the market started changing; technology had improved, and accessories became more popular and pervasive. Off-roading, refrigerators, winches, lights, big stereos, alarms, and satellite-based systems pushed normal SLI batteries and even the Optima Redtop beyond the limit. To support the rising electrical demands of cars, Optima introduced the Yellowtop. Optima’s Jim McIlvaine explained the basis for designing a deep-cycle Yellowtop Optima battery to HOT ROD: “Sulfation forms in the plates when the battery discharges. It’s corrosion that happens over time and one way to reverse that to some degree—you know, batteries are consumable items with finite lifespans, they’re always moving closer to their end—is to recharge them at a higher amperage rate.”
Sulfation—the Great Battery Killer
Optima Yellowtop batteries are specifically designed to handle that higher amperage rate during recharging and the critical difference from competing deep-cycle batteries is the Optima Yellowtop’s ability to better cope with accidental overcharging, hard sulfation, and the reduced life expectancy that results. Says Optima’s McIlvaine: “That high amperage rate can help break up some of that sulfation and restore some performance to a battery, but what sometimes happens is people use too high of an amperage rate whether their battery sulfates or not. And because all batteries are sealed—as are most modern batteries—if they get overcharged, they’ll vent electrolyte and once that leaves the battery it’s never going back in, so the performance is reduced as a result.”
Cranking Power vs. Deep Cycle Ability
For users with a high demand for power when continuous charging capability (like a trickle charger or alternator) isn’t practical, the Yellowtop Optima is the better choice over the Redtop. The deciding factor may be as simple as having an alarm system in a city street environment that sees a lot of triggering overnight, a stereo system that generates a high sound pressure level (SPL) at car shows for hours on end, or an off-road 4×4 that regularly uses a winch to pull disabled vehicles—or itself—out of the mud. The Yellowtop doesn’t have quite the cranking power of a Redtop but has more reserve capacity and an ability to be deep cycled at high amperage repeatedly without chemically breaking down from sulfation.
Optima Redtop vs. Yellowtop
If your car’s charging system and ground circuitry has checked out fine and you need to make a quick decision about whether to get an Optima Redtop or Yellowtop battery, there’s only one major question you need to answer. Take a moment to imagine the worst conditions that made your battery fail in the past. Was it sitting in the garage after a long spell of sitting unattended and not on a trickle charger, or was it away from home after you used it continuously to power a stereo, alarm, air bags, or a winch? If you said yes to the first question, we recommend an Optima Redtop, designed for high-amperage jobs like starting, lighting, and ignition (SLI). If you’ve ever trashed your battery due to a love for electronic devices, then the Optima Yellowtop gets our recommendation.
Whether you pick an Optima Redtop, an Optima Yellowtop, or some other flooded or AGM battery, we want to recommend that you check out Optima’s line of battery chargers. These units have digital processors that assess a battery’s condition and select the proper rate of charge. They can even recondition a partially sulfated battery over time, bringing back some of its lost storage capacity due to “soft” sulfation while preventing an overcharge condition that can damage a car battery. If you’ve got an older “dumb” charger that easily overcharges a battery when unattended (like my old 25-year-old roll-around Die Hard charger) you’d do well to replace it with a unit like the Optima Digital 1200 seen above that you can read about here.
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