User Manual

ABSORPTION CHARGE TIME - FLOODED

Where : T = 0.42 x C /I

T = ABSORPTION CHARGE TIME

C = 20 hr RATED CAPACITY (total battery bank)

I = Charging Current (Amps)

(recommended 10-20% of C/20 discharge rate for Flooded models)

0.42 = ( 20%/50%) + 5% (5% is added due to losses)

EXAMPLE:

2 strings of 6 Volt 6 CS 25P models

20 hr AH rate = 853 AH x (2 strings) = 1706 AH

I = 10% of 1706 AH = 170 Amps (10-20%, 170-340 Amps)

T = 0.42 x 1706/170 = 4.2 hrs

However, if maximum charger output is 120 Amps, 120 is used.

T = 0.42 x 1706/120 = 5.97 hrs

NOTE: Actual Amp output from the charge source(s) should be used. 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 or Return

Amps refers to the lowest output of current (Amps) running to the batteries once

they have reached full capacity. Some charges will measure the actual current

output. If the charge current drops to the End Amps or Return Amps set point before

the programmed Absorption time has completed this will trigger the charger to shut

off or switch to the Float voltage phase, maintaining the bank at 100% SOC.

End Amps or Return Amps for new Series 4000 Flooded models should be set at

2-3% of the 20 Hr AH rating (C/20) of the battery bank.

NOTE: Rolls 4500 & 5000 Series models with Advanced NAM carbon additive may

see higher End Amps or Return Amps values as the cells are less resistant to charge

and current output will remain slightly higher at 100% SOC. A set point of 2-5% may

be used with these models. Adjustments may be required when these are used to

replace other Flooded models.