Battery knowledge

Battery knowledge

Typical VRLA battery applications

Typical Applications
It is vitally important to define your priority before size of battery. These include:
CHARGING
Correct charging of a VRLA battery is essential in optimizing battery performance and life. Although a constant voltage charge should be applied, optimum charging also depends on temperature (Nominally 20 degree), charge current (max 1/4 battery capacity) and ripple current (minimum) . Two basic categories of charging exist.
To find the size of battery you require you generally need two pieces of information, battery load and back-up times. (Note: other factors may also have an effect).

Float/Standby
This charging method is used in applications such as emergency back-up when the battery is required only upon mains failure e.g., continuously on charge and consequently the recommended voltages are slightly lower than cyclic charging so as not to damage the battery.

Cyclic
Cyclic charging is used in applications where the battery is repeatedly discharged then charged, e.g. Portable equipment, Wheel Chairs, Golf trolleys etc.

A higher charging voltage is used but should NEVER be left on indefinitely since is will overcharge and destroy the battery.
Note: For optimum performance always recharge a battery immediately after discharging. Consult the individual battery specification for the correct charging voltage or contact CSP Power Technical Department
BATTERY STORAGE, CARE & MAINTENANCE
The Storage or shelf life of a VRLA battery is usually between 12 and 18 months at 20 degree starting From a charged condition.
Warning :
Battery Care
Warning :
Note : The applied voltage will exceed the normal recommendation and so the battery must be monitored (not left unattended) and removed from charge if excess heat is dissipated. The voltage required to «force» this maximum current into the battery will reduce as the battery recovers until normal charging can take place.
In extreme circumstances a battery may never fully recover from sulphation and must therefore be replaced.
Overcharge
As mentioned in Section 4 optimum charging relies mainly on voltage, current and temperature factors which are interrelated and all of which can cause overcharge.
Excessive charge voltages will force a high overcharge current into the battery, which will dissipate as heat, and may cause gas emission through the safety valve. Within a short period of time this will corrode the positive plate material and accelerate the battery towards end-of-life.
Under these conditions the heat produced inside the battery can lead to thermal runaway due to the increased electrochemical reaction within the battery. The battery may swell before failing and will be irrecoverable from this state. This situation is potentially dangerous.
Temperature
Warning – Heat Kills Batteries.
The recommended normal operating temperature is 20°C.
HIGH TEMPERATURE will reduce battery service life often quite dramatically. In extreme cases this can cause Thermal Runaway, resulting in high oxygen/hydrogen gas production and battery swelling. Batteries are irrecoverable from this condition and should be replaced.
GLOSSARY
Abbreviations
Definitions
ABS RESIN – A Plastic material largely used for the case and cover of batteries.
ACTIVE MATERIAL – The substance which electrochemically reacts in the electrode of batteries. Lead-acid batteries adopt lead dioxide for the positive electrode and spongy lead for the negative electrode.