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Start-Stop AGM Battery Applications

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Absorbent Glass Mat (AGM) Technology

AGM or Absorbent Glass Mat is an advanced lead-acid battery that provides superior power to support the higher electrical demands of today’s vehicles and start-stop applications.

AGM batteries are extremely resistant to vibration, are totally sealed, nonspillable and maintenance-free. AGM offers better cycling performance, minimal gassing and acid leakage when compared with conventional lead-acid batteries.

The end result of all of the features of AGM technology is superior life performance.

AGM Battery Applications

Start-Stop Vehicles, Large Audio Systems, Heated Seats and Other Electronic Accessories

If you’re looking to power a vehicle with numerous electronic features or plug-in accessories, you should consider a deep-cycle battery or a battery made with advanced technology like AGM.

AGM batteries are a great premium choice for high-end and advanced fuel-efficient vehicles with large power demands, and for people who seek greater reliability and longer life in auto batteries. Electronic features such as DVD players, GPS, heated seats and audio systems all add to the demands on a battery.

Start-Stop Vehicles

AGM batteries are also the preferred solution for start-stop vehicle technology, which rapidly gained popularity in Europe and entered the U.S. market in model-year 2013 vehicles.

Start-stop vehicle technology automatically shuts off the engine when your vehicle stops, such as at a traffic light or in stop-and-go traffic, and restarts it quickly and quietly when the clutch is engaged or the brake pedal is released. When the engine is off, the battery is the sole source of power to all the car’s electrical devices, such as air conditioning, the radio and the navigation system. And, in advanced start-stop systems with features like regenerative braking or passive boost, the battery is stressed even more.

In order to power electrical loads during engine-off periods and to support a high number of starts per trip, these vehicles need a battery that is more robust than the typical lead-acid battery. With superior cycling capability, charge acceptance and the ability to operate at a low state of charge, AGM is the technology of choice.

AGM Battery Construction

In AGM batteries, the positive and negative plates are separated by an absorbent glass mat that absorbs and holds the battery’s acid and prevents it from flowing freely inside the battery. The plates are tightly compressed into each cell and held under pressure in the plastic case. The internal compression limits the shedding of plate material caused by cycling and allows for significantly longer life. The element compression also lowers internal resistance and maximizes pulse power output. A rigid container maintains the necessary compression throughout the battery’s life.

The basic design also includes relief venting to release pressure from minor gassing that occurs during charging. The valves open at low pressure and close automatically to prevent air from leaking into the battery.

AGM Battery Benefits

  • Up to 2x longer life than standard flooded batteries
  • Designed for harsh climates and demanding conditions
  • Handles high electrical loads
  • Quickly recharges and extends cycle life
  • Ideal for start-stop applications
  • Vibration resistance
  • Nonspillable and maintenance-free
  • Greater mounting flexibility

If you have a vehicle which has the stop start feature then it is crucial you replace the battery with a specific AGM stop start car battery. These batteries are different than standard wet lead acid batteries which are fitted to vehicles without stop start functionality. Due to the greater demand on the battery caused by regular stop starting standard batteries will wear out very quickly as they are not designed to operate under those circumstances. AGM car batteries are and will last much longer than conventional wet lead acid batteries even if the lead acid battery is of premium quality and specification.

You can check if your vehicle has a Stop Start AGM battery fitted by looking in your owners manual or checking your existing battery. Your battery fitted should say AGM on the top or side specification label. Please contact us if you are unsure

Essential for Modern and Premium marque vehicles such as Mercedes, Land Rover, BMW, AUDI & Porsche with high onboard power demands and stop start technology. AGM car batteries offer fantastic value for money and reliability; this is because they have low self discharge and more starting power than other car batteries with up to 50% more starting power. So when choosing an AGM car battery you can be assured of power, quality and reliability. It is essential you replace your existing AGM battery with the same type of AGM technology as your vehicle will have been designed to have one.

Instead of using normal lead acid constrcution they use a fibreglass type material that makes them spill proof, vibration resistant and holds the electrolyte in place. Our selection of AGM car batteries come mainly made by Bosch, offering you a wide choice of specifications and something for all budgets too.

AGM battery mainly uses its high performance combined with Auto Start-stop technology. However, even if the car does not have a start-stop system, the advantages of the AGM battery can be used: Auto Start-stop technology provides a greater power reserve, and traditional vehicles can also benefit from it, for example due to the longer battery life.

Advantages of Auto Start-stop technology

In addition to the advantages already mentioned, there are other reasons to upgrade to AGM batteries. It is recommended to replace the AGM battery in the following situations:

  • Large short trips of less than 10 kilometers or annual mileage of less than 10,000 kilometers do not allow the alternator to have enough time to fully charge the battery. Every time the battery is not charged to the full SOC (state of charge), the more difficult it is for the battery to start the vehicle next time.
  • If the vehicle is only used on a seasonal basis, the old traditional starter battery may discharge prematurely. This is especially true if there are unfavorable conditions in the storage location and the battery charger is not being used to keep it charged. AGM batteries can better withstand long downtime, because with Auto Start-stop technology, the electrolyte isolated in the diaphragm will not be stratified, thereby reducing sulfide. This means that AGM batteries are easier to charge than wet batteries after a long period of shutdown.
  • AGM batteries can also withstand extreme external temperatures and have high power reserves. The traditional starter battery’s response to extreme heat and cold causes a rapid decrease in capacity and a faster discharge.
  • If the vehicle is equipped with a large number of non-standard electrical equipment, these equipment will increase the power consumption, for example: AGM battery is a complex audio system that can provide the necessary power for the vehicle that cannot be provided by traditional wet batteries.

AGM Batteries – The first choice for light commercial vehicles

In commercial use, vehicles are often used for multi-shift operations. AGM batteries can withstand higher loads during multi-shift operation better than ordinary starter batteries.

City trucks are usually also equipped with electric parts and special equipment. Due to the decomposition of active materials related to its capacity, conventional starter batteries quickly reach their limits and deteriorate. Due to the special design of the battery and the special mixture of active materials, AGM batteries can withstand more and deeper charging cycles than traditional batteries.

City trucks are usually also equipped with electric parts and special equipment. Due to the decomposition of active materials related to its capacity, conventional starter batteries quickly reach their limits and deteriorate. Due to the special design of the battery and the special mixture of active materials, AGM batteries can withstand more and deeper charging cycles than traditional batteries.

Automatic start-stop systems are more effective with an AGM battery

Vehicles that are equipped with a simple start-stop system and do not need to reclaim braking energy (recovery) are usually equipped with EFB batteries. However, even in this case, it is worthwhile to replace the AGM battery: Auto start-stop technology is reliable and trouble-free. Last but not least, the high load capacity of AGM batteries is impressive: During their entire service life, AGM batteries have better charge acceptance than EFB batteries.


AGM eliminates acid spilling in an accident because it is sealed. They can be installed at odd angles.

Have you noticed that more batteries are moving under the trunks and seats of some vehicles? If the battery is not under the hood, it is most likely an absorbent glass mat (AGM) or gel battery. Since AGM is sealed, it can avoid acid spills in accidents. They can be installed at strange angles.

These batteries are powerful due to their size and weight, which allows manufacturers to reduce the weight of the vehicle by several pounds. This is an important reason why they are increasingly appearing on new vehicles. In addition, these batteries have a larger backup capacity to support stop/start systems and flameout functions.

Here are the four AGM myths that you may have heard.

1)You can use your regular battery charger on AGM or gel cell batteries.

Due to the difference in internal resistance, these batteries like to charge slowly.

Many AGM battery chargers have a microprocessor that collects information from the battery and adjusts the current and voltage accordingly. Some have different settings to charge flooded batteries or AGM batteries. Overcharging will kill these batteries. In addition, the alternator is not a charger. Do not rely on the alternator to complete the work of the charger. If the battery is discharged to the point where the vehicle cannot be started, please use the charger as soon as possible to ensure that the battery is fully charged.

2)AGMS and gel cells can be tested the same way as conventional batteries.

These types of batteries have lower internal resistance than flooded batteries. Older capacitor battery testers/analyzers may not be able to accurately read these batteries. Most new battery analyzers have a special mode of AGM/gel battery. Old-fashioned load testers may not  provide conclusive results.

Using a multimeter to measure the state of charge is different from using a traditional flooded battery. After removing the surface charge, the voltage of an AGM with a 100% state of charge may be 13.0 volts. A battery filled with water may only have 12.6 volts.

3)AGM or GEL cell battery replacement is the same as flooded battery replacement. 

Although the battery installation of the two battery types may be the same, some vehicles require additional steps to tell the vehicle that the battery has been replaced.

Newer GM vehicles have a battery sensor module on the negative battery cable. Ford has a battery monitoring system (BMS). Other manufacturers have similar systems. If the battery is replaced, these systems need to be recalibrated using the scanning tool. If the system is not recalibrated, the alternator may overcharge the new battery and cause the replaced battery to quickly fail.

Some vehicles can self-learn the battery by measuring the internal resistance of the battery. But usually the scanning tool can enforce the program, so you know there will be no problems battery.

4)You can’t upgrade a customer to an AGM battery if the vehicle originally came with a flooded battery.

You can install AGM batteries into flooded battery applications. AGM batteries will provide vehicles with greater cold start power and greater heat resistance and vibration resistance. However, you never want to downgrade a vehicle equipped with AGM batteries to flooded batteries.

AGM battery can be said to be a kind of storage battery manufactured for start-stop system. Different from ordinary lead-calcium batteries, the adsorption type glass fiber board of AGM battery can ensure that the electrolyte is absorbed around the plates, so that the battery has more powerful charging and discharging capacity, faster charging and discharging speed and longer long-term deep cycle life. Effectively reduce the hidden danger of power loss and provide strong support for the start-stop system. Of course, the AGN battery without hydrogen system can also be used as an ordinary battery, but this will shorten the life of the AGM battery.

Tag in this article:#AGM #Start-Stop #Starter Battery

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