Battery AGM: characteristics, pros and cons, how to charge
When choosing for my own car, each owner would like her to serve as long as possible and not need any maintenance. These requirements are largely consistent with AGM-batteries, made by a special innovative technology. In addition, these products have a higher starting current, which is so necessary in winter to start the engine.
Features of the internal device
In conventional acid batteries, the free space between the lead electrodes is filled with liquid electrolyte. The principal feature of the AGM battery device is that the so-called absorbent mats made of special porous fiberglass (Absorbent Glass Mat) are located between the plates. The electrolyte inside such batteries is in a “bound” state. In the manufacture it fills the pores of the gaskets in which the liquid is retained during the entire period of operation.Fiberglass mats, tightly located between the lead electrodes, simultaneously perform two functions:
- sponge separator that holds the electrolyte;
- the insulator preventing electric closing of plates.
Since electrochemical reactions occur during the operation and charging of AGM batteries, which are accompanied by the release of oxygen and hydrogen, some of the pores are left empty. Gases fill the free space and, over time, are regenerated back into the water and mixed with the solution with which the mats are soaked. Such internal recombination of the electrolyte ensures the maintenance of its quantity and chemical properties almost unchanged during the entire period of battery operation.
The use of such an innovative technology has significantly improved the technical characteristics and performance of batteries. Among products of a similar purpose, they are by right the best, albeit the most expensive ones.
Varieties of technological performance
Manufacturers of modern AGM batteries use two main technologies (depending on the shape and location of lead electrodesinside the sealed enclosure):
- spiral (orbital).
In the first case, the electrodes are made in the form of rectangular plates. Between them, the mats are filled with electrolyte. Inside the elements are interconnected using special conductive tires. This is the method of manufacture used by most manufacturers.
In the second case, the electrodes are tapes that twist into a “roll”, with fiberglass padding laid between them. The rolls are placed in separate cylindrical containers (into which the product body is divided) and are interconnected by lead plates. Technically, this method is more complicated than the first, which leads to a significant increase in the cost of the battery.
On a note! Due to the fact that this technology is patented, not a very large number of manufacturers are eager to use it.
Regardless of the production method used, only very high purity lead is used for the manufacture of electrodes - up to 99.99% (unlike conventional acid batteries, where requirements are significantly lower).
Important! In order to ensure safe operation in the event of an emergency, the case is equipped with an emergency release valve for overpressure of gases.
The main technical characteristics of batteries are:
- nominal capacity (A / h);
- operating voltage (V);
- maximum starting current (for AGM-batteries it is much more, compared to conventional analogues);
- internal resistance;
- self-discharge current;
- the number of permissible recharging cycles (when the battery is completely discharged), which in the top models of AGM products reaches 400-500;
- service life - up to 7 years or more.
Advantages and disadvantages
Compared to classic counterparts, AGM batteries have a number of advantages:
- For such devices there is no need for any preventive maintenance during the entire life cycle.
- High resistance to vibration loads allows them to be used on any vehicles.
- Absolute operational safety. Due to the fact that the electrolyte is internally in a bound state, that is, even with mechanical damage to the body, its leakage does not occur.
- Products are well tolerated deep discharge, after which they can be easily charged to full capacity.
- They can be installed in almost any position (vertical, horizontal or at an angle).
- Significantly less time is needed to charge the product (compared to liquid analogues).
- Long service life (subject to all rules recommended by the manufacturer).
- When using AGM-batteries, it is necessary to regularly monitor the health of the electrical equipment of the car. For example, a faulty relay-voltage regulator can significantly reduce the lifetime of such a battery (and in the worst case, bring it to a completely inoperative state).
- The need to use for charging special devices equipped with current and voltage regulators.
- Higher cost (compared to standard models).
- Batteries should only be stored in a charged state.
- Reduced starting efficiency (according to AGM batteries) at very low ambient temperatures (minus 30 degrees and below).
Almost all battery manufacturers offer AGM technology to users. Among the most famous in our country and enjoying the proven reputation of reliable companies should be highlighted:
- German - Bosch, Varta and Deta;
- American - Exide, Optima, Deka and Energizer;
- Turkish - Mutlu;
- Austrian - Banner;
- South Korean - Atlas BX and Alphaline;
- Italian - Fiamm;
- Polish - Zap;
- Luxembourgian - Tudor;
- Russian - "Energy" and "Source".
All of the above manufacturers provide a 2-year warranty on AGM-batteries.
Models and prices
The lineup of the model range of innovative AGM-batteries is presented on the Russian market very widely (both in terms of manufacturers, as well as in terms of technical characteristics and field of use). As a comparative material, we present an overview of several models that motorists will be interested in. After all, they are almost daily faced with the use of batteries when starting the engine.
The Varta AGM D52 Silver Dynamic battery (with a capacity of 60 A / H, with a maximum starting current of 680 A and overall dimensions of 242 X 175 X 190 mm) currently costs 11,200 - 11,500 rubles. Warranty period is 2 years.
South Korean Atlas AGM AX S55D23 (worth 8,100 - 8,300 rubles),possessing more modest technical characteristics (capacity 55 A / H, cold scroll current 550 A and dimensions 220 X 170 X 220 mm), it is quite suitable for small or medium-sized cars, stuffed with additional devices that consume a significant amount of electricity.
The cost of the battery AGM Start-Stop Exide EK508, made by orbital technology, is about 16 500 - 16 700 rubles. With a nominal capacity of 50 A / H, the starting current is 800 A! Impressive, given the very small size (260 X 173 X 206 mm).
How to charge AGM-battery
Before you start charging the battery, you should carefully study the manufacturer's recommendations, which are listed in the accompanying documentation. Batteries manufactured by AGM technology completely “painlessly” carry a deep discharge (even reusable), but they have a very “negative attitude” to exceeding the magnitude of the charging current and voltage. How to charge the AGM battery correctly? To date, use two basic algorithms:
- Two-stage, in which the current is set at the first stage - from 10 to 20% of the capacitance value; as well as voltage (as a rule, it is about 14.4-14.8 Volts), which in the second stage is reduced to 13.2-13.6 Volts.This mode is considered the most useful for extending the "life" of the battery.
- Single-stage: voltage - 13.4-13.8 Volts, current - 10-30% of the nominal capacitance value. This option to restore the energy characteristics of the battery can be recommended only to owners of the simplest charging devices.
Since it is correct to charge the AGM battery using the simplest devices intended for servicing ordinary liquid batteries (not so sensitive to exceed the recommended charging current and voltage), it is almost impossible for many manufacturers of AGM products to offer users special chargers manufactured under their own brand (Bosch, Optima and so on).
Users also give good feedback on universal chargers, the release of which has been successfully mastered by numerous domestic firms.
The main requirements for storage for AGM-batteries:
- the ability to adjust the current and voltage;
- maintaining the set values, regardless of line voltage spikes;
- Pre-installed automatic charging modes.
Since it is possible to charge an AGM battery in a short period of time, naturally, they are intended primarily for use in vehicles equipped with an automatic “Start-Stop” system.
These products are also irreplaceable for motorists who use their “iron friend” mainly for short-term daily trips. There will not be enough time to restore the capacity of a standard liquid battery.
Modern cars equipped with numerous additional devices that consume electricity (for example, pre-start engine heaters, powerful multimedia systems, multifunctional security alarms, and so on) also need to be equipped only with high-performance batteries. The best solution is to install AGM-batteries.
These products are also widely used in uninterruptible power supplies for computers, fire alarms and security alarms.
What to look for when choosing
When choosing an AGM battery (12V) for a car (in the case of a replacement product), you should pay attention to a few highlights:
- Overall dimensions (they must correspond to the compartment for mounting the battery) and the location of the terminals (direct or reverse).
- Capacity, the value of which must comply with the parameters specified by the manufacturer in the instructions for a particular car.
- Starting current required for confident start of the engine. Although the value of this indicator for products made by AGM-technology, far exceeds the same characteristic of standard acid batteries.
Important! Before installing a new AGM battery, you should check the condition of the electrical equipment of the car, which is responsible for the charging process while driving.
Despite the fact that AGM batteries need to be charged only with the help of special devices, and the price of the batteries themselves (as compared to conventional liquid analogues) is higher (approximately 1.5-2 times), they are becoming increasingly popular. First of all, this is due to improved technical characteristics (among the products for this purpose), as well as convenience and long term uninterrupted operation.