The best way to keep the batteries at full charge is by putting miles on the vehicle and allowing its charging system to work as it was designed. It’s certainly the most enjoyable way to keep each of those cells topped off, but not always feasible. Right now, a large portion of the nation is covered in the white fluffy stuff and many of our beloved rides are safely stored inside. During this extended storage, maintaining batteries is still vitally important, even if they are not being used regularly. This keeps the battery fully charged, which greatly enhances the performance and life expectancy of the battery.

We spoke with Optima Battery’s Jim McIlvaine about why keeping a full charge in those batteries is so important. He also shared with us how properly maintaining batteries is more important now than ever before. This is important, not only during extended storage, such as during the winter months, but even if our vehicles are used sporadically or started only occasionally.

Why Do Batteries Need Maintaining?

The importance of properly maintaining batteries can be attributed to several factors. One of the most common reasons to put a battery on a maintainer during storage is that batteries can simply lose their charge over time. It doesn’t matter if they are connected to a vehicle or not, batteries self-discharge. The rate of self-discharge can vary depending on the type of battery, as well as other factors, such as the age of the battery and the environment where it is being stored.

If a battery is being stored in a vehicle, that only exacerbates the issue by adding what is known as a parasitic draw, or “key-off loads.” Even during extended storage, many vehicles still draw a minute amount of energy from a battery. You’ll see this more pronounced as you include niceties such as radio presets, car alarms, Wi-Fi, and even key fob transponders or other forms of communication. All of these modern amenities constantly draw energy from the batteries in our rides, even if they are safely stored under a cover during the winter months.

Modern vehicles are far more demanding from an electrical perspective than vehicles from even the early-2000s. – Jim McIlvaine, Optima Batteries

Even if the vehicle is driven sporadically and for short distances, its charging system may not have enough time to fully charge the battery. When you couple a parasitic draw with the additional task of starting the vehicle (especially vehicles with Start/Stop technology), it’s easy to see how a short run to the store is not enough time for the charging system to maintain proper voltage. The cumulative effect over time, is a battery that slowly gets discharged with each use.

What Happens When A Battery Is Discharged?

The key to a long and healthy life of a battery is making sure battery voltage is properly maintained. One of the major differences between regular automotive batteries and “deep-cycle” batteries, such as the Optima Yellowtop, which is designed for both starting and deep-cycle use, is the amount of discharge they can safely tolerate.

Peukert’s Law states that the more deeply you discharge a lead-acid battery, the fewer cycles you are going to get out of that particular battery. So, when is a battery considered discharged? A 12-volt car battery that measures 12.1 volts is considered 50- to 60-percent discharged. Any 12-volt lead acid automotive battery that gets discharged below 12.4 volts and is left that way for any significant time will begin to experience sulfation of the plates inside the battery. This will greatly diminish both the battery’s capacity and lifespan.

What’s The Voltage Of A Fully Charged 12-Volt Battery?

EVs and other oddities aside, it’s safe to say that most modern automotive batteries are of the “12-volt” variety. But what is the voltage of a fully charged 12-volt battery? In this case, an Optima Redtop battery is fully charged between 12.6 to 12.8 volts and a Yellowtop battery is considered fully charged when its voltage reads 13.0 to 13.2 volts.

That is of course the voltage of the battery alone, without the engine running. In a charging state with the engine running and the charging system working properly, you will typically see a voltage between 13.5 and 14.8 volts. Frequent drives, given enough time with the engine running, are typically sufficient to keep batteries fully charged. In the case of show vehicles or weekend drivers, this may not be sufficient to keep batteries fully charged and a maintainer would be a great investment in giving your battery a long, healthy life in your ride.

Battery Maintainers Vs. Chargers

Not all battery chargers or maintainers are alike. That is why Optima offers units classified as either maintainers or chargers. Of course, chargers are more focused on charging a battery, while maintainers, still quite capable of charging a battery, are more closely designed for keeping a battery fully charged for longer periods of time. Let’s look at a few Optima offerings to find out why.

If you’re looking specifically for a battery charger, Optima recommends a charger’s output be in the range of 13.8-15.0 volts with a 10-amp maximum to restore a discharged battery. For float or trickle charging to simply maintain a battery, Optima recommends a lower 13.2-13.8 volts with a maximum of one amp of output.

If looking to restore a deeply discharged battery, you would do well to consider either Optima’s 1200-series or 400-series charger. These units will vary both voltage and amperage, depending on the needs of the battery. The 400-series charger can supply up to four amps of current and the 1200-series can provide either 12 or 15 amps respectively.

Both of these chargers will regulate the level of charge provided, depending on the needs of the battery, so they can also be great options to keep a battery maintained. In the case of properly maintaining a battery during extended storage periods, the Optima D200+ may be the best choice. The D200+ charges at a maximum rate of two amps, and will still charge a battery, but will take longer than the 400- or 1200-series chargers.

Optima chargers and maintainers come with a quick disconnect so you can easily change between the provided spring clips or the terminal-mounted leads with ease.

As mentioned, driving is the most enjoyable way to keep those batteries fully charged. But, if we’re trying to keep the odometer from spinning like a Las Vegas slot machine, or protecting our beloved machines from the elements or distracted drivers, it’s nice to know that there are battery maintainers available. That way, those batteries will stay fully charged so our rides are ready whenever we are.