Valve regulated lead acid battery (VRLA battery) utilizes a dilute sulfuric acid electrolyte which is immobilized so as to eliminate the hazards of spills and leakage and which facilitates an oxygen recombination cycle. The oxygen combination cycle eliminates the need to add water throughout the battery's life and improves its safety of operation. VRLA battery doesn't require regular addition of water to the cells, just different from the general lead acid battery. However, how long does the VRLA battery last for? The purpose of this article is to review the life expectancy of VRLA batteries.
The majority of VRLA batteries used in Uninterruptible Power Supply (UPS) applications have a five year design life. This design life is the basis for the manufacturer's pro-rated warranties.
The service life of a battery is the actual time span from the date of installation until the battery capacity drops below 80% of its rating. VRLA batteries that are well maintained and are installed in a properly conditioned environment, typically have a service life = 70%-80% of their design life.
Factors that adversely affect the life expectancy of a VRLA battery include:
- a. High Ambient Temperatures:
The optimum temperature for a VRLA battery, upon which most manufacturers' warranties are based, is 77℉（25℃）. For a battery maintained at constant charge, there is a 50% reduction in life expectancy for every 15℉ increase in ambient temperature above 77℉. The batteries must also be installed with the proper spacing per the manufacturers' recommendations in order to maintain the necessary ventilation.
- b. Discharge Cycles:
VRLA batteries are rated for a certain number of deep discharges and shallow discharges. The load during discharge, length of discharge, rate of discharge, rate of recharge and recharge time all factor into the affect on life expectancy. Manufacturers rarely publish specific data on the number of discharges for which a battery is rated; however, VRLA batteries are typically designed for 2-3 deep discharges per year and several hundred shallow discharges per year.
- c. Charging Characteristics
VRLA battery in UPS applications should be maintained at a float voltage that does not exceed the maximum set by the battery manufacturer. Overcharging the batteries will cause degradation and eventual failure. Constant overcharging can lead to Thermal Runaway, in which a continuous cycle of rising temperature and rising current result in venting of gases and a possible rupture of the case. If hydrogen gases are allowed to escape in a large enough concentration, a source of ignition could cause a fire.
If you want to know more about VRLA battery, you can just visit Leoch International, which is an excellent manufacturer of lead acid battery. The company is a public company which has over 10 year's history and it is very reliable and dependable. If you are interested in the company, you can search for more information in the internet. The office website is http://www.leoch.com.
About the AuthorHi, this is lissa, and I am try to tell something about leoch battery, such as lead acid battery, GEL battery, VRLA battery, UPS battery, motorcycle batteries, golf cart battery, car battery, etc, hope you like it. And if you currently have some suggestions or advices, I am really appreciate if you tell me.
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