· 5.1 Two Stage charging (Constant current to Constant voltage)
This is the recommended method of charging SLA batteries.It is necessary to strictly control the actual charging voltage to ensure it is within the appropriate safeguards.

Fig 5.1 shows the charge characteristics at a constant current (0.1C(A))and a constant voltage 2.40V/(cell)after discharge of 50% and 100% of the 20HR rated capacity.

The time required to complete the charging varies by the amount of the previous discharge, initial charge current and temperature.

As shown in Fig 5.1 if a fully discharged battery is charged by constant current and constant voltage of 0.1C(A)and 2.40V/cell respectively at 25℃, it will regain more then 100% of the previous discharge within 24 hours.

Since the battery does not restrict the initial charge current, this shortens the charging time .

· Fig 5.1 Charging characteristics(25℃)

· 5.2 Floating Charge
Floating charge voltage must be kept at a value high enough to compensate the battery self-discharge so the battery can be in a fully charged condition at all times.

The optimum charge voltage for Double Tech Battery is 2.25V per cell under normal temperature conditions (25℃)

· 5.3 Supplementary Charging
Part of the battery capacity will have been lost due to self-discharging during transportation or storage. Give the battery a supplementary charge before putting it into service.

The supplementary charge should be given by every six months according to the charge conditions in Table 5.1.

· Table 5.1: Supplementary Charge Conditions

· 5.4 The Charging Voltage And Ambient Temperature Relationship
The charging voltage should be 2.40 volts per cell at 25℃. However, as the average ambient temperature rises, the charging voltage should be reduced to prevent overcharge. As the average ambient temperature is reduced, the charging voltage should be raised to prevent under-charging. Accordingly, the recommended compensation factor is-3mV, per cell at 25℃ of the standard point.

· Fig 6.0 Difference rate discharge curves(25℃)
The higher the discharge current, the shorter the discharge time. Double Tech Batteries have an excellent high discharge capacity. The relation between discharge current and time is shown in fig 6.1

· Fig 6.2 Self-Discharge Characteristics
The self-discharge is affected by ambient temperature and storage time. The higher the temperature and longer the storage time the greater the self discharge. See Fig 6.2.

  · Fig 6.3 The Open Circuit Voltage And Residual Capacity Relationship
Residual capacity can be estimated by measuring the open circuit voltage as shown in Fig 6.3.

 

· Fig 6.4 Effect Of Temperature On Capacity
The battery capacity is affected by ambient temperature and discharge current as shown in Fig 6.4.




· Fig 6.5 Life Characteristics Of Cyclic Use
The battery life is influenced by usage methods, discharge depth, charge condition and so on , The relation between difference discharge depth and cyclic use life is shown in fig 8.1.




· Fig 6.6 Life Characteristics Of Float Use
The float life at room temperature 6V12V series is 3-5 years, 2V series is 10-15 years. See Fig 8.2.

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