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About VRLA Battery

Technology Manual

2V Battery Installation

6V&12V Battery Installation

About VRLA Battery

A battery is an electricity storage device which can be found in any number of shapes, size, voltage and capacities.
When two conducting materials (often dissimilar metals) are immersed in a solution, an electrical potential will exist between them is connected together through a closed circuit, a current will flow. The value of this potential (or voltage) is dependent on the materials used, giving rise to a whole family of battery types each having benefits and restrictions in use. Examples are: - lead acid, nickel cadmium ( NiCad ), lithium, silver alkaline.
This manual is concerned only with one battery technology ?C the most successful ?C lead acid (lead and lead oxide immersed in sulphuric acid). Each cell has a 2 volt potential.
A battery is simply a number of cells connected together with a given voltage and capacity. The more cells the higher the voltage, the large the plates the higher the capacity (in general).
Purely for convenience, batteries are made in 12 volt blocks with 6 cells but are also available in 6 volt, 4 volt and even 2 volt, single cell blocks.
Batteries can be connected in series to achieve whatever voltage is required (add the number of 2 volt cells) and in parallel to achieve the capacity required (add the capacities of each parallel battery or string of batteries) . For larger systems, a number of series connected strings maybe connected in parallel with each other. This achieves both a higher voltage and capacity.

VRLA Sealing Principles:

The charge/discharge reaction of the non VRLA battery can be expressed by the following equation:

In the case of the traditional open-type lead-acid battery overcharge after completion of the charge causes electrolysis of the water content of the electrolyte, which generates O2 gas at the positive plate and H2 gas at the negative plate. These gasses are discharge to the outside. Since a drop in the electrolyte levels results, adding water is occasionally needed.
The VRLA battery is designed so that the negative plate does not have to be fully charged even when the positive plate is fully charged. Further, no H2 gas generates from the negative plate although O2 gas generates from the overcharged positive plate. O2 generated from the positive plate then reacts with the charged sponge lead (Pb) of the negative plate and turns into lead monoxide (PBO). The lead monooxide in turn reacts with sulfuric acid (H2SO4) in the electrolyte to turn into lead sulfate (PbSO4), allowing the negative plate to discharge. In other words, O2 from the positive plate is absorbed by the negative plate without being expelled to the outside. Since the negative plate develops discharging with the help of O2, there always exists portions free from discharging. As a result, the negative plate never generates H2. This completely prevents the loss of water.

The sealing principle of a VRLA battery maybe expressed as a reaction equation:

CAUTION: ALWAYS USE A BATTERY BEST DESIGNED FOR THE APPLICATION.
This guide is focused on Industrial Standby applications and NOT Automotive or Traction use.
Industrial Batteries
Industrial batteries are available from two distinct groups with the following features. Note: VRLA have superseded open-vented in many applications

OPEN-VENTED	VRLA/SEALED
1. Older technology 2. Require separated battery room 3. Regular routine maintenance 4. Separate safety requirements 5. Store/use in vertical position 6. Can require extensive cabling	1. Environmentally friendly 2. Use directly in office environment 3. Low maintenance-"maintenance free" 4. Self-contained. Safe 5. Store/use in any orientation 6. Can be used internal or adjacent to load
VRLA has in many instances replaced the open-vented type.

Note: The term sealed lead-acid SLA is an old acronym Considered misleading and is now replaced by Valve Regulated Lead Acid VRLA.

VRLA Battery Applications

Cycle Use:
• Portable VTR/TV, tape recorders, radio and so on
• Power tools, lawn mowers, vacuum cleaners
• Cameras and photographic equipment
• Portable personal computers, word processors, portable terminals, and so on
• Portable measuring equipment
• Portable telephone sets
• Various power toys and hobby equipment
• Lighting equipment
  Standby Use:
• Communications and electric equipment
• Emergency lighting equipment
• Fire alarm and security systems
• Various telemeter equipment
• Office computers, microcomputers, and other office automation equipment
• Robots, control equipment, and other factory automation equipment
• UPS power supply
• Emergency power supply in power generation plants and substations
  Solar Cell Power Generation:
• Street lighting
• Water pumping system
• Portable power system
• Small town power system
  Product Applications:

BATTERY DISPOSAL/RE-CYCLING
Finally, when a battery has reached the end-of-life it must be returned to the point of sale or to a licensed battery dealer for recycling. Please observe the following points.