Rolls Surrette User Manual

VRLA AGM ABSORPTION CHARGE TIME

Where : T = 0.38 x C /I

T = ABSORPTION CHARGE TIME

C = 20 hr RATED CAPACITY (total battery bank)

I = Charging Current (Amps) (recommended 20% of C/20 discharge rate)

0.38 = ( 20%/50%) + 5% (5% is added due to losses)

EXAMPLE:

2 strings of 6 Volt S6-460AGM models

20 hr AH rate = 415 AH x (2 strings) = 830 AH

I = 20% of 830 AH = 166 Amps

T = 0.38 x 830/166 = 1.9 hrs

VRLA AGM FLOAT STAGE AND TERMINATION

To maintain 100% SOC, the charger continues output to the battery bank at the

programmed Float voltage and End Amps current indefinitely or until the charger

is shut off or unplugged. The profile in Table 5: VRLA AGM Charge Voltage may

be used with or without the Float stage. Without the Float stage, recharge may be

terminated based on time. This will vary by depth of discharge and charge current,

or percentage recharge (105-110%).

ROLLS VRLA AGM BATTERY CHARGE

VOLTAGE PARAMETERS

NOTE: Use the highlighted voltage set points when charge equipment is supplied

with a temperature sensor. Set at 4mV/ºC/Cell...(+/- 96mV per ºC from a 25ºC

Delta - 48V System) Higher or lower settings may cause incorrect adjustments

in charge voltage. Without a temperature sensor, charge settings must be

adjusted manually based on the battery temperature when in use, not just

ambient temperatures.

TABLE 5: VRLA AGM Charge Voltage

NOTE:

If charger output is 120

Amps max, 120 is used.

T = 0.38 x 830/120 = 2.9 hrs