AGM Deep Cycle Battery Review: AGM Battery

Technology Used: Advanced battery technology

Perfect fit: AGM battery is a reliable upgrade to any flooded lead acid battery

Excellent value: AGM deep cycle battery lasts up to two times longer than conventional batteries

Reliable: They are extremely heat and cold tolerant

Robust: A deep cycle AGM battery is best for vehicles equipped with lots of electronics

Worry free: Slower discharge in storage

Durable: AGM has an outstanding vibration resistance

Safer: AGM batteries are sealed deep cycle batteries with no spill hazard or free-flowing electrolyte

Powerful: AGM batteries have high performance alternative

Resilient: They have excellent ability to tolerate deep cycling

 

Some of AGM Striking Benefits you can’t afford to let go by:

Vibration resistance due to sandwich construction

Stands up well to cold temperature

AGM battery is less prone to sulfation if not regularly topping charged

Battery is spill-proof through acid encapsulation in matting technology

AGM battery has less electrolyte and lead than the flooded battery version

Deep cycle AGM battery has high specific power, better responsive to load, with low internal resistance

AGM battery have better cycle life than the flooded systems

AGM battery is up to 5 times faster charge compare to flooded technology

Water retention (hydrogen and oxygen combine to produce water)

 

Quick Summary of Deep Cycle AGM Battery

AGM battery, also known as absorbent glass mat is a class of lead-acid deep cycle battery in which the electrolyte is absorbed into a fiberglass mat. They generally have flat plates like wet cell lead-acid battery, or may be wound in a tight spiral plate. The internal resistance of AGM deep cycle batteries is lower than traditional cells; they self-discharge more slowly and can handle higher temperatures.

These batteries have a valve which activates when the battery is recharged at high voltage. This valve activation allows for the escape of some of the active thus decreasing the overall storage capacity of the battery. The vents/lids typically have gas diffusers built into them that allow safe dispersal of any excess hydrogen that may be produced during charging.

AGM batteries are maintenance free; and they can often be oriented in any manner. This is in direct contrast with normal lead-acid batteries which must be kept upright to avoid acid spills and to ensure the plates are sitting in the electrolyte.

The deep cycle AGM battery is totally sealed and are safe and easy to transport

A deep cycle AGM battery never needs topping up with water

Deep cycle AGM battery can be safely mounted inside a boat, Motorhome, car, caravan, etc.

AGM batteries do not need to be in a sealed box vented to the outside like wet batteries. They are sealed batteries which only need to be vented to atmosphere. They can be mounted at any angle (on their sides or ends if needed).

While most deep cycle batteries will get destroyed if deeply discharged, deep cycle AGM batteries remain the only batteries that can be deeply discharged without major damage.

AGM deep cycle batteries have low internal resistance, hence they will generally accept a much larger charge current, and fully charge at a lower voltage, thus when charging from a standard car/truck alternator, an AGM deep cycle battery will become fully charged, quickly and in less than 3 hours.

AGM batteries have slower discharge rates, usually, they only self-discharge at the rate of up to 3% per month, and even after 12 months sitting idle they can still be recharged and put back into full service without any major damage. This cannot be said to conventional deep cycle battery. A standard deep cycle battery if allowed sitting idle for 12 months would destroy itself and no longer hold a good charge.

AGM batteries were originally developed for the military, they are very robust.

 

AGM Deep Cycle Battery Review: Deep Cycle Battery

When we talk of battery in the context of renewable energy, we are mostly referring deep cycle batteries. Deep cycle battery gets its name from the ability to be discharged up to 20 percent (deep cycled) repeatedly without causing damage to the battery. True deep cycle AGM batteries have the thickest plates and are primarily used for solar power plants or in industrial applications for backup, where extended discharge times are most important. The AGM battery versatility potential makes them better deep cycle battery for cranking a motor. The only catch is for the selected battery to have an ampere hour rating at least 20 percent above what is recommended for starting that particular motor

A deep cycle battery is an energy storage unit in which a chemical reaction occurs that produces electrical energy or electricity for short. These batteries are designed to be discharged and recharged many times, hence the name Deep Cycle Battery.

A deep cycle battery is similar to a car battery in that they are lead acid battery, but they differ in many aspects. For example, while a car battery is designed to deliver a high burst of energy for a short time, a deep cycle battery provides a more constant (steady rate) charge or power over a long period and is thus commonly used with golf carts, motor homes, boats and other recreational vehicles.

While a starting battery has thinner plates and is more prone to warping and pitting when discharged, a deep cycle battery is designed with thicker plates, have less instant energy, but greater long-term energy delivery or discharge time. Their thicker plates make them capable of storing huge electrical energy (charge) and thus can survive a number of discharge cycles.

Deep cycle batteries after being heavily discharged over longer periods, recover fully. This is thanks to their thicker plates with a high content of antimony design features.  When used overnight, their use might deplete about 50-70 percent of the battery capacity. The energy depletion rate largely depends on the house loads of the boat. This call for the need to recharge which again re-deposited energy in the bank, and the cycle, or process, starts over. Generally, the selected deep cycle batteries should be sized to store three to four times the expected amount of energy to be used between recharge cycles.

There are different types of deep cycle batteries such as AGM batteries (Absorbed Glass Mat), flooded batteries, gel batteries and recently lithium-ion. All of which are made differently.

The flooded battery is the most commonly used deep cycle batteries. It is made up of lead acid similar to the standard lead acid battery in car batteries. The gel batteries, also famously has a gel-like substance in them while the AGM batteries consist of acid suspended in a glass mat separator. The next generation lithium-ion battery systems are projected to experience significant uptake among grid-connected and off-grid households in the future.

 

AGM Deep Cycle Battery Review: Deep Cycle Battery Ratings

They are basically two ways to rate batteries, volts and amps.

Amp hour (Ah) is the measure of the capacity of chemical energy available in a battery that is converted into electrical energy. It also refers to as the discharge rate. The discharge rate is a measure of the time it takes to discharge a battery before it needs recharging. In other words, it’s the amount of energy that the battery can store.

The capacity of the battery is reduced if the battery has a faster discharge rate or if it takes a shorter period, for instance over 1 hour to completely discharge. Thus, the amp hour capacity will be reduced by about 50% and so will the amount of cycles.

When a battery is discharged at a constant rate of current over many hours, it’s referred to as the “C” rating. For instance, many small batteries are rated at the C20 rate. This implies, the battery will deliver its amp hour capacity if discharged (in used) over 20 hours. Lager batteries in large stand-alone power systems are rated C100 rate, meaning they are designed to discharge (used) over 100 hours or 4 days with a life span typically of about 15 years.

More recently, batteries for residential applications are often referred to by their kilowatt-hour (kWh) capacity.

 

AGM Deep Cycle Battery Review: Discharge Cycles

Selecting the right battery for a particular use can be confusing. While all batteries claim to be particularly well suited to an energy storage purpose, all deep cycle batteries are not designed or created equal, even within their own type such as Gel, Sealed Lead Acid or AGM.

The goal of most deep cycle battery users is to select one that will last many years since purchasing a deep battery is quite an investment. The cycle rating is one of the best ways to determine a battery life span. This is the measure of the number of times a battery can be discharged and recharged during its life span. IEC 896-2 discharge cycle, based on a 100% discharge, is the best benchmark.

The IEC 896-2 provides a good baseline for drawing comparisons between different brands and also different battery lines from the same manufacturer, although discharging a battery 100% is not recommended because it significantly decreases the life of any deep cycle battery.

 

AGM Deep Cycle Battery Review: Battery Charging

The battery sulfates or its performance and life span decreases if it’s not recharged thus charging a battery immediately after being used (discharged) is of almost important. Again, you won’t be able to reuse it once discharge since it won’t also supply enough energy (if any at all) to drive the system. 

The alternator, which is the battery charger, works well if battery is not deeply discharged. If an alternator is used to charge a deeply discharged battery, it tends to overcharge it which may intern damage the batteries. This is the more reason why they are never used to charge an engine-starting battery as they quickly destroy the battery, reducing its life span by about 50% each time they are charged with an alternator.

Deep cycle batteries are charged in a special way, especially when they have been deeply discharged. This special type of charging is called 3-step regulated charging. Only special smart battery chargers using computer technology can perform 3-step charging techniques.

Step 1: Bulk Charging

This is where up to 80 percent of the battery energy capacity is replaced by the charger at the maximum current amp rating and the voltage of the charger.

Step 2: Absorption Charge

This phase sets in when the battery voltage reaches 14.4 volts. At this stage, voltage is kept constant at 14.4 volts and the current (amps) declines until the battery is 98% charged

Step 3: Float Step

The last step where the battery is fully (100%) charged or close to it. This is achieved by regulating the current at less than 1 amp and the voltage at not more than 13.4 volts. The float charge will not heat or boil batteries, but will maintain the batteries at 100% readiness and prevent cycling during long term inactivity.

Some AGM and gel cell batteries may require special settings or chargers for better charging.

 

AGM Deep Cycle Battery Review: Battery Testing

A battery can be tested in several ways with the most accurate method being the measurement of battery voltage and specific gravity. The battery voltage is measured with a digital D.C. Voltmeter and the specific gravity with a temperature-compensating hydrometer. A quality load tester may be best to test sealed batteries.
Before using any of the testing methods, start by getting the battery to full charge and then remove the surface charge. To surface charge is removed by discharging the battery for several minutes usually with the use of a headlight (high beam). After turning off the light, you’re ready to test the battery.

Charged State	Specific Gravity	Voltage
		12V	6V
100%	1.265	12.7	6.3
75%	1.225	12.4	6.2
50%	1.190	12.2	6.1
25%	1.155	12.0	6.0
Discharged	1.120	11.9	6.0

 

Another method of battery testing is Load testing. Load test removes amps (current) from a battery in much the same way as starting an engine would. You can get a load tester at most auto parts stores. A load test can only be performed on a battery that is near or at full charge.

Most battery companies label their battery with the amp load for testing. This number is generally half of the CCA rating. For example, a 400 CCA battery would load test at 200 amps for 15 seconds.

The following are some tips from the results of your testing:

Hydrometer readings should not vary more than 0.05 differences between cells.

Digital voltmeter readings for the voltage should be as shown in this document. The gel cell and sealed AGM battery voltage at full charged will be slightly higher in the 12.8 to 12.9 range. A shorted cell is usually indicated by voltage meter voltage readings within 10.5 volt range.

The volt meter and load test are the only possible ways to test a maintenance-free wet cell.  Maintenance-free batteries that come with a built in hydrometer (green/black window) generally give the condition of 1 of 6 cells. The problem with such reading is that, you may get a good reading from 1 cell but have a problem with other 5 cells in the battery.

 

What is a Deep Cycle AGM Battery?

Absorbent glass mat (AGM) is a class of lead-acid deep cycle battery in which the electrolyte is absorbed into a fiberglass mat. There are also known as SLA (seal lead acid) and VRLA (valve regulated lead acid). Designed and built as a long life, reliable, durable and safer battery solution, these batteries have proven to be an outstanding upgrade from the traditional flooded lead-acid battery.

Known for their enhanced electrical reliability, AGM deep cycle batteries are ideal for vehicles that are heavily equipped with electronic devices, including car audio systems and navigation, stop-start technology and electric parking brakes. To be able to sustain the load that sophisticated electrical systems require, the AGM battery must-have higher voltage to reliably maintain this sophisticated equipment.

Manufactured with highly absorbent fiberglass mat separators or polyester, batteries benefit from the fact that the battery acid (electrolyte) cannot flow freely and is evenly distributed across the active plate surfaces. They operate by using recombinant chemistry. This is the process whereby Oxygen recombines through the separators which live between the positive and negative plates. Additionally, the plates and separators are held within their cells under compression. This result in up to 20 times better resistance to vibration. Another AGM benefit is that they discharge much more slowly when the car is not operated for a very long period of time (up to 12 months). The deep cycle AGM battery is safer because there is no free electrolyte (battery is sealed). The AGM batteries eliminate the spill hazard that characterizes most lead-acid batteries. This resulted in an increased level of safety to its user.

The greatest advantage of AGM is product life, up to twice as long as compared to most other batteries. From a performance perspective, the AGM deep cycle battery boasts better recharge capability while allowing up to 3 times more starts per cycle and produces more power per cycle. This AGM battery construction, cycle-ability and design work to greatly enhance its lifespan than the traditional lead acid.

It’s important to you to do your research and familiarize yourself with the available options. If you are selecting a new car battery, seat cover, or tire, its best to start by verifying what options are available which will go a long way to help you make the best possible choice.

 

AGM Deep Cycle Battery Review: Brief History

As Absorbed Glass Mat (AGM) battery technology quickly took the frontline in battery production in 1980 mainly for used in aircrafts. It wasn't long before it fully replaced production of the gel technology and flooded lead acid batteries. Concorde Company, also known as one of the worlds’ top AGM battery manufacturers quickly carved out a niche in many industries. There are a number of processes and materials that contribute to the overwhelming success of the Concorde AGM batteries. One of the biggest contributors to quality is the lead-oxide paste that Concorde engineers have developed. Concorde goes the extra distance to fully seal the edges of the poly ethylene separators to prevent the most common failure in other AGM batteries. They make all inter-cell connection welds extra robust and over the top of the partitions so all welds can easily be inspected for quality.

Concorde has developed an industry leading AGM battery that is marketed throughout the Recreational Vehicle (RV) and Marine industries, aside from its aviation, solar and mobility AGM batteries. For more than two decades the Lifeline Battery brand name has become synonymous with absolute top quality AGM battery technology.

As part of the same families that run Concorde Battery Corporation are the Lifeline Battery distribution, marketing and sales. Lifeline Batteries overwhelming success in the RV and Marine industries is a direct result of the top performance of the batteries themselves. Lifeline RV and Marine batteries are constructed using the same technology and manufacturing processes that Concorde employs in the production of its' aerospace aviation batteries.

The RV and marine industries have benefitted over the years from several AGM battery technology enhancements as well as the advent of numerous battery groups sizes. Lifeline Batteries have established themselves as the top quality AGM battery in the RV and marine markets and are known to be a top performing battery.

Concorde's aerospace industry batteries are distributed to many branches of the US Military and Armed Forces networks. Lifeline Batteries are also marketed to a long list of other industries that includes photovoltaic, stand by and back up powers applications, electric vehicle, mining, oil & gas, and the list continues to grow.

 

AGM Deep Cycle Battery Review: Less Recharging But More Power and Longer Life

Deep cycle AGM marine batteries are sometimes referred to as non-spillable batteries, dry cell batteries, maintenance free batteries or regulated valve batteries. They are often interchangeable with gel cell batteries.

An AGM battery typically doesn't require a special battery charger. The technique is to recharge it before the battery discharge below 50%. AGM batteries are safe for indoor use and maintain low discharge rates during long term storage. These premium batteries were first marketed to the aviation industry.

Over the years, and with numerous technological advances in hardware and chemistries, Concorde stood as the manufacturer of one of the highest quality batteries in the industry (the AGM battery). It never took long before Concorde began marketing multiple brand named batteries into an array of industries around the world.

 

Advantages of AGM Battery as lead acid battery
AGM has a special glass mat designed to wick the battery electrolyte between the battery plates. They contain only enough liquid to keep the mat wet with the electrolyte and if the battery is broken no free liquid is available to leak out.
AGM technology incorporates sulfuric acid which is absorbed by a very fine fiberglass mat, making the battery spill-proof. This property allows for handling and shipment without hazardous material restrictions. The AGM battery plates can be made flat, similar to a standard flooded lead acid pack in a rectangular case or can also be wound into a cylindrical cell.
AGM deep cycle battery has very low internal resistance, which rendered it capable to deliver high currents on demand and offers a relatively long service life, even when deep cycled. Deep cycle AGM battery is maintenance free, lighter than the flooded lead acid type, and provides good electrical reliability. While regular lead acid batteries may need regular topping charge (six months monthly) to prevent sulfation buildup, AGM batteries are less prone to sulfation and can sit in storage for longer before a charge becomes necessary. AGM battery stands up well to low temperatures and has a low self-discharge.

The leading advantages of AGM are a charge that is up to five times faster than other batteries, and the ability to deep cycle. AGM battery offers a depth-of-discharge of 80% whereas others specified 50% DoD to attain the same cycle life. Their disadvantages lie in the slightly lower specific energy and higher manufacturing costs. 

Most AGM batteries are mid-sized and range from 30 to 100Ah, commonly built to size and are found in high-end vehicles to run power-hungry accessories such as steering wheels, heated seats, windshields and mirrors. Most vehicle manufacturer and other auto racing leagues choose AGM products because they are vibration resistant.

AGM battery is the preferred battery for upscale motorcycles. They are sealed batteries which help to reduces acid spilling in an accident, allow installation at odd angles and lower the weight for the best performance. AGM batteries are used for marine, robotic and motor home applications due to their good performance at cold temperatures.

AGM battery is making inroads into the start-stop function of modern cars. The classic flooded battery type is simply not robust enough and repeated discharging and charging (cycling) causes a sharp drop in its capacity after just two years of use.

AGM battery is sensitive to overcharging (charge to 2.40V/cell (and higher) is just fine). However, the float charge should be dropped to between 2.20 and 2.30V/cell. Automotive charging systems for flooded lead acid often have a fixed float voltage setting of 14.40V (2.40V/cell); a direct replacement with a sealed unit could overcharge the battery on a long drive.

AGM and other sealed batteries do not like heat and should be installed away from the engine compartment. Battery manufacturers recommend halting charge if the battery core temperature reaches 120°F (49°C).

AGM Batteries traits includes being non spillable, deep cycle, safe for use in limited ventilation areas, may be mounted in any position, low self-discharge, and may be transported via Air or Ground safely without special handling.

An AGM deep cycle battery is preferred when a high burst of amps is required. Recharge can be accomplished by using a good quality standard battery charger or engine alternator. Their life expectancy; measured in years or as cycle life remains excellent in most AGM batteries if the batteries are not discharged less than 40% between recharge.

They have low internal resistance. This means they will become fully charge at a lower voltage, and accept a much larger electrical energy. Thus when charging with standard car/truck alternator, they become fully charge in about 2 to 3 hours.

 They can occasionally be discharged much deeper than conventional deep cycles without major damage.

These AGM valve regulated batteries offer very good value, and when compared to standard deep cycle batteries in a dollar per usable amp hour format, they come out miles ahead, plus all the added advantages that I have already outlined, but there is still more.

 

AGM Deep Cycle Battery Review: Battery Limitations

They has a higher manufacturing cost compare to the flooded (but cheaper than gel)

AGM batteries are more sensitive to overcharging (gel has tighter tolerances than AGM)

Their capacity gradual decline (gel has a performance dome)

They have lower specific energy

AGM deep cycle battery must be stored in charged condition (less critical than flooded)

They are not environmentally friendly (has less electrolyte and lead than flooded)

 

AGM Deep Cycle Battery Review: Battery Maintenance

A properly maintained battery is important for the ultimate in service life. Deep cycle batteries, including AGM batteries should never really be discharged to below 20% of their full capacity. This is because they have lower internal resistance that can easily be destroy by heat and damage when they are recharged.

Deep cycle battery generally require a significant amount of monitoring or oversight, but the next generation of energy storage (lithium-ion) features highly automated management systems; with basically zero need for maintenance and monitoring.

To better maintain and improve performance and life of your AGM deep cycle battery, consider the following points on a regular basis:

The battery should be kept cleaned using a baking soda and water solution; a couple of tablespoons to a pint of water.

A serviceable battery needs to have the fluid level checked. Use only distilled water; distilled is best as all impurities including those that could contaminate the cells have been removed and there is nothing left that could contaminate your cells.

Cable connections should be cleaned and tightened to prevent battery problems. Most battery problems, including explosion are often caused by dirty and loose connections.

Never overfill battery cells, particularly in warmer weather because the natural fluid expansion in hot weather can push excess electrolytes from the battery.

Corrosion of cables on top-post of batteries can be prevented by using a small bead of silicone sealer at the base of the post and place a felt battery washer over it. Coat the washer with petroleum jelly (Vaseline) or high temperature grease, then place cable on the post and tighten. Cover the exposed cable end with the grease. The most cause of corrosion is gases released from the battery which condensed on metal parts.

Renewable energy systems usually use a low-voltage cut-off switch, low voltage or low-charge warning light to prevent the type of damage that will shorten the battery’s life.

Battery shelf life may be extended by storing them at lower temperatures; because lower temperature reduces the chemical reactions in the batteries. However, in order to obtain highest voltage, AGM battery must be returned to room temperature. This explained why most deep cycle battery manufacturers don’t recommend refrigerating batteries.

 

How to Recover a Deeply Discharged AGM Deep Cycle Battery

Resuscitating a deeply discharged AGM battery simply means being able to recharge an AGM battery that has been discharged to below 10.5 volts. The main problem here is that most battery chargers have built-in safety features that function mainly to prevent chargers from recharging deeply discharged batteries. Generally, batteries that are at 10.5 volts or less are considered defective, having a short circuit, a bad cell or some other defect. Most chargers are binary (analog) and are either off or on. They don’t come on; when the charger thinks the battery is “bad.” Forcefully turning on to charge a “bad” battery could create an unsafe condition or act. But AGM deep cycle battery may be just fine. This is because it has a simply slipped below the minimum voltage threshold of the charger to turn on, and the charger may do nothing since it may not know what to do with the battery.

Below are three simple techniques for bringing a deeply discharged AGM battery back to its normal performance.

OPTION 1: USE ONLY AGM SPECIFIC CHARGERs

The best method for recharging a deeply discharged AGM battery is simply to use a modern charger that has kept up with battery technology. Most new chargers have desulfation steps and AGM-specific settings that allow reconditioning and recovery of deeply discharged AGM batteries. These chargers also have the additional capability of doubling as a battery "maintainer" for storage batteries. Some also come with additional ring terminals to permanently attach to your battery leads. This makes it easy to hook up when you store your boat, RV car or truck.

The OPTIMA Chargers Digital 1200 12V Performance Battery Charger and Maintainer enhances the performance of AGM and OPTIMA batteries, extends battery life and recovers deeply discharged batteries. This charger is optimized when used with high-performance AGM batteries, and it also enhanced charging capabilities that can also be used with all conventional types of automotive batteries

This is the best and preferred method of charging a deeply discharged battery.

 

OPTION 2: THE DIY Technique FOR CHARGING A DEEPLY DISCHARGED BATTERY

This recovery technique involves you tricking the traditional charger into recharging a deeply discharged AGM deep cycle battery.

You will use the following:

• Battery charger (under 15 amps)
• A good battery, preferably above 12.2 volts fully charged
• Jumper cables
• The seemingly dead, deeply discharged AGM battery
• A watch or timer
• A voltage meter

How to go about the recharging process:

Connect the good battery and deeply discharged AGM battery in parallel negative to negative and positive to positive. Do not have the charger turned on at this stage or connected to the battery.

Now, connect the good battery to the charger and turn on the charger. This will enable the charger to detect the voltage of the good battery (connected in parallel), and start charging.

After the batteries have been left connected for an hour or so, check to see if the AGM battery is slightly warm or hot to the touch. Batteries generally become warm during charging, but excessive heat is an indication of bad battery or wrong connection. Discontinue charging immediately if the battery is hot to the touch or if you hear the battery "gassing" a hissing sound coming from the safety valves. If it's gassing or too hot, STOP CHARGING IMMEDIATELY!

Use your voltage meter to frequently check back if the AGM battery has charged to 10.5 volts or above (generally takes less than two hours with a 10-amp charger). Disconnect the charger from the wall outlet and remove the good battery from the charger. Then, connect only the deeply discharged AGM battery to the charger and turn on the charger to continue charging the AGM battery until the automatic charger completes the charge process or until it reaches a full charge. In most cases, the AGM battery will recover.

ROPTION 3: ENLIST THE PROFESSIONALS

This option is for those who don't own a battery charger, who doesn’t want to make the investment or who not the do-it-yourself kind of person.

Contact the service of a professional battery specialist who knows AGM technology. Most specialists do provide "charge and check" procedures for a small fee or free of charge. Auto parts stores are typically not capable of accurately determining an AGM battery's condition and many use conductance testers that don't provide correct readings. Battery specialists are experts who can help determine if your battery is recoverable or not.

 

AGM Deep Cycle Battery Charging Tips

Let’s take a look at some of the important tips to properly charge an Absorbent Glass Mat (AGM) battery for best performance and longer life.

Most new battery chargers, including the OPTIMA Charger, Digital 1200 12V Performance Battery Charger and Maintainer, are endowed with microprocessors that collect information from the battery and adjust the voltage and current accordingly. Some have different settings for charging different batteries (flooded, gel and AGM batteries).

All lead-acid batteries might experience the formation of lead sulfate crystals (sulfation) upon discharge. Hence it’s better to go for a charger that is endowed with a desulfation mode to help condition your battery and keep it performing at its best.

Low and slow chargers are the best. A low amp charger (1 to 12 amps) is generally the best choice for charging any lead-acid battery, including AGM batteries. If charge with higher amp chargers, they get full quickly, but also can generate a lot of heat. This may reduce the life of a battery, similar to the effect of summer heat.

Alternators are NOT chargers. Never rely on your alternator to charge your deep cycle AGM battery. If your battery is deeply discharged to the level where it cannot start your vehicle, use a charger (not an alternator) as soon as possible to make sure your battery gets fully charged.

Note that, alternators are meant to maintain a battery, not charge it.

If your batteries eventually die (batteries are a consumable product, none will last forever) get a new replacement. The goal is to consistently maintain your battery charge to get the most life out of it.

Different chargers have different capabilities. Generally, most 12-volt automatic battery chargers will work on a deep cycle AGM battery under normal conditions and many other newer battery chargers have settings specifically for AGM batteries. Some (such as the OPTIMA Chargers Digital 1200 12V Performance Battery Charger and Maintainer) even go as far as having separate settings for OPTIMA YELLOWTOP and REDTOP batteries.

AGM and gel technology differ. Keep in mind that the technology of a deep cycle AGM battery system is not the same as a gel battery. Thus if your charger offers different modes, you must endeavor to select the matching settings for best charging experience and maximum performance. If on the other hand you use the gel setting to charge an AGM deep cycle battery, it won't fully charge and it can actually damage your AGM battery over time.

The magic threshold voltage is 10.5 volts. Avoid letting your AGM battery discharged below 10.5 volts. The charging scenario for a deeply discharged AGM battery, especially one that's dipped below 10.5 volts, may be slightly different. Such AGM batteries can only be recover with the OPTIMA Digital 1200 charger as they can possibly recover batteries that have been discharged deeply to 1.25 volts.

 

Battery Safety, Explosions and other Hazards

Most battery explosions are caused by the misuse or malfunction of a battery, such as short circuiting a battery or attempting to recharge a non-rechargeable battery.

Explosions often occur when a short circuit resulted to or generates very large currents. In addition, deep cycle batteries release hydrogen when they are overcharged. Normally the gas dissipates quickly but also easily be ignited by a nearby spark (e.g. when removing the jumper cables). On the other hand, hydrogen gas isn’t a problem with lithium-ion batteries.

By attempting to charge a battery beyond its electrical capacity (overcharging), may lead to a battery leakage, irreversible damage, or explosion of a deep cycle battery. Not only that, it may also cause damage to the electrical components in which the overcharged battery is used.

When a conventional battery (car starting battery) is recharged at an excessive rate, an explosive gas mixture of hydrogen and oxygen may be produced faster than it can escape from within the walls of the battery, leading to pressure build-up and the possibility of the battery case bursting (exploding).

In extreme cases, the acid may spray violently through the casing of the battery, cause severe injury.

Deep cycle batteries may also explosions in maintenance if the valves are blocked or fail. This cause pressure rise within the cells until maybe a short circuit ignites the hydrogen-oxygen mixture. The resulting explosions can cause severe injury. Such problems can be detected in most batteries if the battery feels hot to touch or if the sides appear swollen.

 

Battery Tips for Best Performance

The following tips are true for all battery types and should be regarded as the tool for best practise and improved battery performance, not forgetting your safety.

• Stay with one battery chemistry (gel, AGM or flooded). Each battery type requires specific charging voltages. Avoid the mixing battery types which can result in under- or over-charging. Also, its best practice to change all batteries at the same time.
• Regulate charge voltages based on battery acceptance and temperature (manually or automated) to maximize battery life and reduce charge time. Make sure the charging system is capable of generating sufficient amperage to charge battery banks efficiently. This means using an alternator with 25% to 40% as many amperes as the capacity of your entire battery bank.
• Keep batteries clean, cool and dry.
• Never mix new batteries with old ones in the same bank. This may seems like there would increase the resulting capacity, old batteries instead tend to pull down the new batteries to their deteriorated level.
• Regularly check terminal connectors to avoid loss of conductivity.
• To flooded lead acid batteries, add distilled water as needed and keep them charged.
• Clean corrosion with a paste of water and baking soda.