What are EFB batteries, what are their differences and advantages?

Not so long ago, a new type of battery made using EFB technology has appeared on the market. These batteries have improved characteristics and features that are worthy of attention. Often, many drivers confuse EFB with AGM, so we will try to understand the distinctive features and advantages of this type of battery.

EFB technology

These batteries work on the same principle as all lead acid batteries. The current is generated by a chemical reaction between lead dioxide and acid. EFB stands for Enhanced Flooded Battery, which stands for Enhanced Flooded Battery. That is, it is the liquid electrolyte that is poured inside.

Lead plates are a distinctive feature of EFB technology. For their manufacture, only pure lead without impurities is used. This allows the internal resistance to be reduced. Also, the plates in EFBs are twice as thick as conventional lead acid. The positive plates are wrapped in a special microfiber material that absorbs and retains liquid electrolyte. This prevents intensive shedding of the active substance and significantly slows down the sulfation process.

This arrangement made it possible to reduce the proportion of electrolyte and make the battery practically maintenance-free. Evaporation occurs, but very little.

Another difference is the electrolyte circulation system. These are special funnels in the battery housing that provide mixing due to the natural movement of the vehicle. The electrolyte rises through them, and then again falls to the bottom of the can. The liquid remains homogeneous, which increases the overall service life and improves the charging speed.

Difference from AGM batteries

AGM batteries use fiberglass to separate the plates in the battery cells. This fiberglass contains an electrolyte. That is, it is not in a liquid state, but sealed in the pores of the material. AGM batteries are completely sealed and maintenance free. There is no evaporation unless a recharge occurs.

AGMs are significantly inferior in terms of price to EFBs, but surpass them in some characteristics:

• self-discharge resistant;
• stored and operated in any position;
• withstand a large number of discharge / charge cycles.

It is most relevant to use AGM batteries for storing energy from solar panels or in various portable stations and devices. They give out high starting currents up to 1000A, but 400-500A is enough to start a car starter. In fact, such capacities are needed only when there are a large number of energy-consuming consumers in the car. For example, heated steering wheel and seats, powerful multimedia systems, heaters and air conditioners, electric drives and so on.

Otherwise, the EFB battery handles day-to-day tasks just fine. Such batteries can be called an intermediate link between conventional lead-acid batteries and more premium AGM batteries.

Scope

The development of EFB batteries pushed engineers to the spread of cars with a start-stop engine start system. When the vehicle is stopped, the engine is automatically shut off and started when the clutch pedal is pressed or the brake is released. This mode greatly overloads the battery, since the entire load falls on it. A conventional battery simply does not have time to charge while driving, as it gives up a large share of the charge to start.

Deep discharges are detrimental to lead-acid batteries. EFBs, on the other hand, do a good job in this mode, since they have a large capacity and are resistant to deep discharges. The active material in the plates does not crumble.

Also, EFB batteries perform well in the presence of powerful car audio systems in the car. If the voltage is less than 12V, then the amplifiers will emit only weak wheezing. EFB batteries provide a stable and constant voltage for all systems to function properly.

Of course, improved batteries can also be used in middle class cars. They cope well with temperature changes, they are not afraid of deep discharges, they give a stable voltage.

Charging features

EFB charging conditions are similar to AGM. Such batteries are “afraid” of overcharging and short circuits. Therefore, it is recommended to use special chargers. The voltage is supplied proportionally, and should not exceed 14,4V. Manufacturers usually place information on battery characteristics, operating conditions, capacity and allowable charging voltage on the battery case. These data should be adhered to during operation. This way the battery will last longer.

Do not charge the battery in an accelerated mode, as this can lead to boiling of the electrolyte and evaporation. The battery is considered charged when the indicator drops to 2,5A. Special chargers have current indication and overvoltage control.

Advantages and disadvantages

The advantages of improved batteries include:

1. Even with a capacity of 60 A * h, the battery delivers a starting current of up to 550A. This is quite enough to start the engine and significantly exceeds the parameters of a conventional 250-300A battery.
2. The service life is doubled. With proper use, the battery can last up to 10-12 years.
3. The use of thicker pure lead and microfiber plates increases battery capacity and charging speed. The EFB battery charges 45% faster than a regular battery.
4. The small electrolyte volume makes the battery virtually maintenance-free. Gases are not absorbed. Minimum evaporation rate. Such a battery can be used safely in a car or at home.
5. The battery works well in low temperatures. The electrolyte does not crystallize.
6. The EFB battery is deep discharge resistant. Recovers up to 100% capacity and is not destroyed.
7. The battery can be stored for up to 2 years without a large loss of capacity.
8. Suitable for use in vehicles with the Start-Stop Engine system. Withstands a large number of engine starts during the day.
9. It can be operated at an angle of up to 45 °, therefore such batteries are often used on motor boats, boats and off-road vehicles.
10. With all these characteristics, the price for improved batteries is quite affordable, much lower than for AGM or gel batteries. On average, it does not exceed 5000 - 6000 rubles.

The disadvantages of EFB batteries include:

1. The charging conditions must be strictly observed and the voltage must not be exceeded. Do not allow the electrolyte to boil.
2. In some respects, EFB batteries are inferior to AGM batteries.

EFB batteries have emerged against the backdrop of increased energy requirements. They do their job well in the car. Expensive gel or AGM batteries are more powerful and deliver high currents, but often such capacities are not needed. EFB batteries can be a good alternative to conventional lead acid batteries.