Samlex America SCC-30AB - Manuel (Page 26)

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4
PRINCIPLE OF OPERATION & FEATuREs
(evolution of Hydrogen and Oxygen due to electrolysis of water in the electrolyte) and
hence, it is necessary to exit this stage as soon as 100% capacity is restored. If this over
voltage condition is allowed to continues after 100% recharging, the battery will be
damaged due to effects of overcharging like overheating, loss of water, corrosion of
the Positive plates and excessive build up of pressure resulting in acid spillage due to
opening of pressure activated relief valves (sealed batteries). The balance of 20% of
the battery capacity is restored in this stage. As the battery capacity rises from 80% to
100%, the PWM control tapers the current by continuously reducing the Duty Cycle
from < 100% to > 0%.
Note: Change over to the next Float Voltage Regulation Set Point “Vf” is possible only after
the battery voltage is held at the selected Absorption Voltage Regulation Set Point “Va”
for continuous or cumulative period of 1 Hour. If “Va” cannot be maintained continuously /
cumulatively for 1 Hr, transition to Float Stage will NOT take place (the periods during which the
battery voltage falls below “Va” are not counted towards 1 hour time period).
During this stage, LCD Screen 4 (Fig 5.3) displays “ State: Absorption”. LCD Screen 5
(Fig 5.3) shows the programmed Absorption Voltage Regulation Set Point (Displayed
on the screen under “Bulk”).
The Status LED will blink GREEN 5 times.
NOTE: During Absorption Stage, if the load current is more than the current from
the solar panel, the battery voltage will drop. If the battery voltage drops around
1V below the Absorption Voltage Regulation Set Point “Va” for around 1 min, the
controller reverts to Bulk Stage. PWM DUTY Cycle is changed to 100% and the LCD
Screen 4 (Fig 5.3) changes to “State: Bulk”.
Stage - 3: Float Stage. The controller enters this stage from the previous Absorption
Stage at point “D” after the battery voltage is held at the selected Absorption Voltage
Regulation Set Point “Va” for continuous or cumulative period of 1 Hour.
During this stage (Curve portion “D” to “E”), the Switch operates under PWM control
by feeding pulsing Short Circuit Current “Isc” with very low Duty Cycle of 0% to < 10%
to keep the battery voltage constant at the Float Voltage Regulation Set Point “Vf”.
During this stage, the battery is 100% charged and a very low “Trickle Charge” of
around 0.1% of the Ah Capacity is required to be fed to the battery to compensate for
self-discharge. The battery can be left at this stage for prolonged period of time.
During this stage, the LCD Screen 4 (Fig 5.3) displays “State: Float”. Screen 5 (Fig 5.3)
displays the programmed Float Voltage Regulation Set Point (Displayed on the screen
under “Float”)
The Status LED will be steady GREEN.
NOTE: During Float Stage, if the load current is more than the current from the solar
panel, the battery voltage will drop. If the battery voltage drops around 1V below