How To Bring an AGM Battery Back From the Dead

It is a well-known fact that once they have passed away, they do not accept responsibility for their actions, despite the fact that you admire their capacity to tolerate punishment and their paint-friendly disposition.

To our good fortune, there is a method that can return them back to life.

Let’s begin with some background. The majority of the spill-proof batteries that are now available on the market are AGM batteries, which is an abbreviation for absorbed glass mat.

Gel batteries are a common name for these batteries. Examples of typical batteries are the Optima and Odyssey brands.

In contrast to a gel battery, which results in the formation of a semisolid with the addition of a silica agent to the electrolyte, an AGM battery makes use of a typical sulfuric acid solution, much like any other regular automobile battery (about 60/40 water and acid when the battery is fully charged).

In contrast, the electrolyte is absorbed and kept in place by layers of boron-silicate glass matting that are sandwiched between the lead plates in this instance.

While it is true that both types of batteries are capable of being regarded leakproof and spill-proof, the AGM technology is now considered to be the superior technology, particularly for usage in automobiles.

A number of AGM batteries make use of cylindrical cells that are spiral-wound (Optima), while others make use of flat plates and box cells (Odyssey), just like traditional batteries.

It is also important to note that the term “sealed” is rather misleading because lead-acid batteries are often able to vent when it is required.

Batteries are put through a lot of stress thanks to hot-rodders, but the intense heat and vibrations that we put them through aren’t even the worst of it.

We frequently allow our automobiles to remain idle for lengthy periods of time, such as in the intervals between race events or cruise evenings, or even for the entirety of the winter season. Examples of such instances include.

A further point to consider is that the electronic devices found in modern automobiles, such as engine and body computers, entertainment and security systems, and so on, frequently make use of keep-alive memory operations.

These functions cause a minor but consistent current drain on the battery.

What is meant by the term “hard sulfation”?

When it comes to automobile batteries, this is a terrible thing to happen because they all self-discharge over time, even the more costly deep-cycle types (just at a slower rate).

At ambient temperature, a normal battery loses roughly 5 percent of its capacity every month simply by lying on the shelf.

Furthermore, once the voltage of the battery drops below around 1.75 volts per cell, a process known as hard sulfation begins to take place, which results in the battery suffering irreparable harm. In essence, the plates become coated with muck, which is composed of thick lead sulfate crystals, which results in a reduction in the capacity of the battery.

A battery is considered to be a dead player if it is left to drain for an extended period of time or if it is not properly recharged in between discharges.

This is because the plates of the battery become fully sulfated, and nothing can bring it back to life. To be honest, hardly much at all.

We bought two new Optima AGM batteries, a conventional RedTop model and a deep-cycle YellowTop one, and subjected each of them to a steady 2.2-ampere load in order to recreate these devilish circumstances. Over the course of many days, we removed the load and attempted to recharge the batteries by utilizing a conventional roll-around charger that was designed for the repair business and had a capacity of 2/10/40 amps.

This type of charger is commonly referred to as a bulk charger in the industry. At no time did we experience any difficulty in getting either battery to accept a charge; that is, until the discharge that occurred around the clock brought the batteries down to a voltage of around 4.2 volts on average.

The batteries then refused to charge, which is a typical complaint that is repeated frequently: “it won’t take a charge.”

On the other hand, the problem is not actually coming from the battery, nor is it necessarily coming from the charger.

To get to the heart of the matter: In the event that the voltage of the battery drops below a particular threshold, the charger will no longer be able to detect the existence of the battery and will thus refuse to supply the current.

In rare instances, this can take place at any voltage that is lower than 10.5 volts. This hangup is more likely to occur with older and more fundamental chargers as opposed to more modern and sophisticated versions, which are comprised of control circuitry that is designed to address these concerns.

So, there are two options accessible to us: either we can get a whole new charger that is very pricey and comes with the additional brainpower, or we can use a straightforward approach that the developers at Optima have given us.

Procedures for Charging an AGM Battery

This is all that is required of you: You should get another car battery that has a good charge on it (at least 12.4 volts), and then use a set of jumper wires to connect it in parallel with the battery that is giving you trouble on your vehicle.

After that, turn on the charger and charge the battery in the usual manner, being sure to carefully adhere to the recommendations provided by the manufacturer regarding the maximum current and voltage. That is the simplest explanation.

The second battery is responsible for giving the voltage that makes the charger believe that it is receiving the required current. After approximately one hour, you are able to remove the second battery and proceed with the charging process.

To our satisfaction, it is effective. Regardless of the extent of the drain that we applied, we were able to restore the battery to a fully charged state by utilizing our bulk charger, which is not only inexpensive but also reliable.

You may now discover chargers that are designed exclusively for AGM batteries and are available for purchase.

Even while they are pleasant, they are in no way required. Recently manufactured chargers, on the other hand, include a switch position on their control panels that is labeled “AGM/gel.” Several makers of AGM batteries have said that this stance is somewhat erroneous due to the fact that the charging needs for gel batteries and AGM batteries are quite distinct from one another.

The standard switch settings are the ones that they recommend picking while using these chargers.

Using a float charger is, of course, the best way to prevent all of these issues that are associated with deep discharge and parasitic loads in the first place.

These devices, which are often referred to as battery tenders, provide the battery with a slight but consistent charge of between 500 and 800 milliamperes, so ensuring that it remains completely charged and in good condition. When you are not using your vehicle, all you need to do is connect the float charger to a power socket then connect it to your battery.

After that, you are ready to go. We have seen basic versions of these chargers on sale for as low as twenty dollars, which is the deal of the century, especially when compared to the hundreds of dollars that you would pay to replace an AGM battery that has died.

As an additional advantage, you will be able to rest certain that the battery will be ready and waiting for you whenever you decide to drive your rod.

The good chargers and maintainers that are manufactured by firms like as Optima have a greater number of bells and whistles as well as improved electronics that can diagnose problems.

As part of the HOT ROD torture test, this Optima AGM battery was purposefully subjected to a discharge that was both lengthy and sluggish, with a current of 2.2 amps, until it displayed a voltage of less than 4 volts across the terminals.

The common complaint that an AGM battery “won’t take a charge” is caused by the fact that many conventional battery chargers will fail to offer an effective charge when the voltage level is decreased. It is simply not possible for the charger to “see” the battery in the circuit since the battery does not have adequate potential.

If I want to recharge an AGM battery, what voltage do I need to use?

Here’s the secret to success: When a dead AGM battery cannot be charged using conventional methods, just connect a second battery that is fully charged and has a voltage of 12.4 volts or higher in parallel with the dead unit.

The connection should be positive to positive and negative to negative. Make sure that the charger is connected to the pair. Because of this, the charger will be tricked into giving the required current to the battery that has been discharged effectively.

By employing this technique, we were able to revive a number of batteries that had been severely drained. In addition, this method is also applicable to traditional batteries, but with a degree of effectiveness that is not nearly as high.

Optima recommends that the regular charging current be restricted to 10 amperes in order to get the longest possible battery life.

Other manufacturers recommend limitations that are comparable. Batteries that are referred to as sealed batteries might be particularly sensitive; therefore, it is imperative that no vehicle battery be permitted to experience substantial heating while it is being charged.

An excessive amount of charging current and temperatures will cause a battery to age before its time and may even be hazardous; when you overcharge a battery, you are effectively producing hydrogen that is potentially explosive.

As a result of the usage of spiral-wound plates in cylindrical cells, certain AGM batteries, such as the Optimas that are seen here, have the look of a six-pack.

Since spiral-wound cells do not have to support their own mass, it is claimed that they make it possible to employ purer lead in the plates.

This is only one of the many benefits of spiral-wound cells. Conventional architecture, according to other manufacturers of AGMs, is preferable because it provides a higher plate area for a given case capacity.

While the YellowTop is a dual-purpose battery that may be used for both performance and deep-cycle applications, the RedTop is the highest-performance model in the Optima range of batteries. (A race vehicle that does not have a charging system seems like the perfect use for this.)

A regular Optima battery is represented by a case that is dark gray, while a deep-cycle variant is represented by a case that is light gray. Batteries that are designed for deep cycles have a lower peak current but are able to tolerate deeper discharges.

Applications in the maritime industry call for a BlueTop Optima. It is capable of starting your vehicle, however it is not designed for usage in automobiles.

To Determine Which Battery Terminals Are Appropriate to Use

Many aftermarket batteries come with both top and side terminals, and there is no reason why you can’t use all of them.

This is done to ensure that the battery can cover the widest possible range of models. In point of fact, battery manufacturers advise that you connect the primary cables of the car to the side terminals when you are working with high-load applications.

Instead, you should use the top posts for high-current add-ons such as winches, inverters, and other similar devices. You should not dispose of the plastic terminal caps; rather, you should keep them in case you decide to store the battery at a later time.

It is not a good idea to just run a bolt into the fragile side terminals of a GM-style battery while you are bench testing and charging it. Due to the fact that there are just a few threads within, they are susceptible to being stripped or scorched as a result of arcing.

Additionally, the terminal lug might be loosened in the event when the bolt reaches its lowest point. If you want a connection that is both secure and tight, you should always use a washer and jam nut on the bolt.

Additionally, make sure that the terminals are kept clean. Corrosion of the battery terminals is the single most common cause of unneeded battery replacements, in addition to a multitude of other electrical issues.

Keeping a float charger attached to the battery throughout extended periods of time when the vehicle is not being used will completely eliminate the risk of experiencing problems with deep discharge and sulfation.

A battery tender, which is another name for a float charger, is a device that applies a very little but consistent current to the battery in order to keep it charged to a nearly full level at all times.

How To Bring an AGM Battery Back From the Dead – careerscholars.com