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Figure 4

 

 

 

Two stage of constant voltage charging is a recommended method for charging valve regulated lead acid battery in a short period of time and then maintain them in a fully charged float or 
standby condition. Figure 3 illustrates the characteristics of a two stages constant voltage charging. 

 

Taper Current Charging 

This method is not recommended for VRLA batteries for it has somewhat harsh on battery 
performance. However, because of the simplicity of the charger circuit and its low cost, taper 
current  charging  is  often  used  to  charge  a  number  of  series  connected  batteries  that  are 
subject  to  cyclic  use.  If  this  method  is  to  be  used,  it  is  suggested  that  the 

FULI

  technical 

department should be contacted. 

 

Effect of Temperature on Charging Voltage 

 
As  temperature  rises,  electrochemical  activity  in  a  battery  increases.  Similarly,  as 
temperature falls, electrochemical activity decreases. Therefore, conversely, as temperature 
rises,  charging  voltage  should  be  reduced  to  prevent  overcharge  and  increased  as 
temperature falls to avoid undercharge. In general, to assure optimum service life, use of a temperature compensated charger is recommended. The recommended compensation factor for

 

DC

  batteries

  is  -3mV/

/Cell  (standby  use)  and-5mV/

/Cell  (cyclic  use).  The  standard  center  point  for  temperature  compensation  is  20

.  Figure  4  shows  the  relationship

 

between 

temperatures and charging voltages in both cyclic and standby applications. 
 

Effect of Voltage on Battery Gassing 

Although the batteries are of the recombination type and the amount of gassing at normal operating voltages and temperature are 
negligible, if the charging voltage is increased, gassing will occur despite the recombination design of the product. Gassing does 
not normally occur while the battery is operating under float conditions and normal constant voltage recharge of 2.27-2.30 Vpc at 
20

. Very little gassing occurs when the battery is recharged under normal cycling recharge procedures. However, it can be seen 

on the accompanying graph the higher voltages that this especially under conditions of constant current charging will substantially 
increase the volume of gas. 

 

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The discharge capacity of a lead acid battery varies and is dependant on the discharge current.

 FULI

 VRLA battery capacity is 

measured at  the  20-hour  rate. 

The  standard  industry  practice  to  determine  the  nominal capacity  of  a  valve  regulated lead  acid 

battery is to discharge the battery under test at its 20-Hour rate to a final voltage of 1.75 volts per cell. The curves in Figure 5 show 

the different currents that can be drawn at various discharge capacity rates at an ambient temperature of 20 

.The rated nominal 

capacity of a battery is reduced when it is discharged at a value of current that exceeds its 20-Hour discharge rate. This should be taken into consideration when a battery is being selected 

 

Figure 3

 

Summary of Contents for Deep Cycle series

Page 1: ...te leakage can occur from the terminals or case of any FULI battery This feature insures safe and efficient operation of FULI batteries in any position FULI batteries are classified as Non Spillable and will meet all requirements of the International Air Transport Association I A T A Dangerous Goods Regulation Long Service Life Float or Cyclic The FULI VRLA battery has a long life in float or cycl...

Page 2: ...RLA batteries It is necessary to closely control the actual voltage to ensure that it is within the limits advised Float Service 2 25 2 30 Vpc at 25 Cycle Service 2 4 2 45 Vpc at 25 FULI suggests that the initial current be set within 0 2 C Amps Figure 1 shows one example of a constant voltage charging Constant Current Charging This method of charging is generally not recommended for VRLA batterie...

Page 3: ...p between temperatures and charging voltages in both cyclic and standby applications Effect of Voltage on Battery Gassing Although the batteries are of the recombination type and the amount of gassing at normal operating voltages and temperature are negligible if the charging voltage is increased gassing will occur despite the recombination design of the product Gassing does not normally occur whi...

Page 4: ...oximately 3 per month when stored at an ambient temperature of 25 The self discharge rate will vary as a function of ambient storage temperature Figure 4 shows the relationship between storage times at various temperatures and the remaining capacity Shelf life In general when lead acid batteries of any type are stored for extended periods of time lead sulphate is formed on the negative plates of t...

Page 5: ... current of 0 1C Amps or 15 to 20 hours at constant voltage of 2 45Vpc Within 12 months after manufacture 8 10 hours at constant current of 0 1C Amps or 20 24 hours at constant voltage of 2 45Vpc In order to successfully top charge a battery stored for more than 12 months the open circuit voltage must be checked to ensure that it is higher than 2 0 volts per cell Therefore ALWAYS check the open ci...

Page 6: ...an be performed once or twice per year Safety When carrying out any work on the battery the applicable safety standards should be followed Note it is recommended that a battery log be maintained and that records should be kept of the total voltage measurements any mains failures major battery discharges current and time etc The main factors causing reduction in the life expectancy of FULI DC Serie...

Page 7: ...ts into contact with your skin or eyes generously wash the affected area with clean water and consult a physician immediately 4 Batteries explode if put into the fire Never dispose of batteries in the fire 5 Mixed usage of batteries differing in capacity type manufacturer or history of use charge discharge operation must be AVOIDED for this may damage the batteries and the equipment due to the dif...

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