Accumulators for backup sources

  Station batteries (backup accumulators) are the most often lead-acid sealed batteries based on the VRLA (Valve Regulated Lead Acid), which is a system of pressure control in batteries with use of a pressure relief valve. During operation, the pressure in the accumulator increases due to the formation of gases on the electrodes, and this pressure is maintained and regulated by means of valves (rubber cap). The valves are necessary, because the hydrogen produced increases the pressure inside the accumulator. When a certain overpressure is reached, the gases are released and the pressure inside the accumulator drops. The release of overpressure through the valve is repeated periodically and the frequency depends on the operating conditions (especially the temperature and voltage during charging). When the overpressure is released, the water vapor currently present in the gases inside the accumulator is also released, causing a gradual drying out of the electrolyte. Thanks to this technology, the accumulator is suitable for enclosed spaces (backup sources), is safe (there is no risk of leakage of hazardous substances such as sulfuric acid), and has an extended shelf life.

VRLA batteries are divided into two subgroups - AGM batteries and GEL batteries

  The AGM (Absorbed Glass Mat) lead-acid battery is a type of VRLA battery in which the electrolyte (sulfuric acid with a density of 1.3 g / cm³) is soaked in a nonwoven fabric made of glass microfiber. AGM batteries are almost 100% hermetic and maintenance-free, characterized by low self-discharge (1-3% of capacity in Ah per month) and the ability to deliver high currents. They are used for applications in uninterruptible power supplies (UPS), electronic fire protection systems (EPS), electronic security systems (ESS), and telecommunications.

  GEL accumulators are a subset of lead VRLA batteries with the electrolyte solidified in the form of a gel - sulfuric acid is mixed with a very fine glass powder with a particle size in the order of micrometers, which causes the electrolyte to gel. It can be operated in any position due to the non-liquid nature of the electrolyte. Thanks to this technology, however, they are more expensive than AGM batteries.

  Another type of lead-acid batteries with liquid electrolyte are EFB (Enhanced Flooded Battery) batteries, which are also maintenance-free. They have a special polyester fiber separator and thicker electrode plates. However, you will not find EFB batteries on our website - they are mentioned here for information only.

  The average service life of standard VLRA / AGM lead-acid batteries is 3 to 5 years depending on the conditions in which they are operated (discharging and charging currents, frequency of charging and discharging cycles, ambient temperature, etc.). Accumulators of Long Life or Deep Cycle series (eg YUASA, Goowei, Ultracell, CSB) have this average lifespan double - 8 to 12 years. However, they are usually significantly more expensive.

  The optimum service life is given in cycles at a temperature of + 20 ° C and with a regular discharge to 50% D.O.D. (D.O.D. - depth of discharge, 50% of the stored energy is taken from the battery). After 50% of the capacity discharge, immediate charging to the full capacity of the battery in Ah should follow. This is important especially in cases where the battery is operated at low temperatures, especially around the freezing point (0 ° C and below). A fully charged battery withstands frost up to the manufacturer's guaranteed temperatures, usually -20 ° C (the electrolyte does not freeze), although it has a reduced capacity in Ah.

  UL94 - standard for safety of (non) flammability of plastic materials. This standard is published by Underwriters Laboratories, USA. The standard specifies the tendency of the material to either extinguish or spread the flame after ignition of the sample. It is harmonized with IEC 6070, ISO 9772, and 9773.

  UL94-V0: burning stops within 10 seconds on a vertical sample; drops of particles of molten material are allowed if they are not ignited.