User manual

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ABSORPTION CHARGE TIME - FLOODED
Where: T = 0.42 x C /I T = ABSORPTION CHARGE TIME
C = 20 hr RATED CAPACITY (total AH capacity of battery bank)
I = Charging Current (Amps) (*see Note: CHARGING CURRENT below)
0.42 = (factors in assumed current loss during Absorption charge phase)
EXAMPLE:
2 strings of 6 Volt 6 CS 25P models
C = 20 hr AH rate = 853 AH x (2 strings) = 1706 AH
I = 10% (recommended) of 1706 AH = 170 Amps
T = 0.42 x 1706/170 = 4.2 hrs
However, if actual measured current is less (~160 Amps), or maximum charger output
is limited to 160 Amps, 160 is used. (Ex. 2 x 80 Amp controllers)
T = 0.42 x 1706/160 = 4.48 hrs
NOTE: CHARGING CURRENT - Actual measured current output (Amps) to the battery
bank should be used in this calculation. Recommended charge current for Flooded
models is 10% of the 20 Hr AH rating of the battery bank (C/20) (min 5%, max 20%)
Charge source(s) and chargers should be properly sized, based on the rated capacity
of the battery bank, to ensure adequate charge output. Maximum charger output
applies when the generated output meets or exceeds this threshold.
FLOAT CHARGE
When the Absorption charge phase has completed and the batteries have reached
100% SOC, the charger will continue to output at a lower voltage setting known as
Float. Float voltage maintains the battery bank at a constant 100% SOC until the
charge output diminishes (Ex: solar) and/or a load is applied which begins to discharge
the battery bank. To prolong battery life, the Float settings on the power supply
should be adjusted to the voltage indicated in Table 2 (a) & 2 (b) Flooded Charging
Parameters. Higher or lower voltage settings may result in unnecessary overcharge
or sulfation buildup.
END AMPS OR RETURN AMPS
As batteries near full capacity, charge current decreases. End Amps, Return Amps or
Tail Current refers to the lowest output of current (Amps) flowing to the batteries as
they have reached full capacity. Some chargers will determine this set point has been
reached by monitoring current output to the battery bank. If the charge current drops,
reaching the End Amps/Return Amps/Tail Current set point before the programmed
Absorption time has completed, this will trigger the charger to shut off or switch to
the Float voltage phase which holds the battery bank at 100% SOC. The charger will
complete the full programmed Absorption time if this set point is too low or
programmed at 0%.
The recommended End Amps/Return Amps/Tail Current set point for Rolls Flooded
models is 2% of the 20 Hr AH rating (C/20) of the battery bank. Typically, when
current drops to the 2% set point for 1 hour, the battery bank has reached 100% SOC.