RV Power Products - Solar Boost 3048
5
CHARGE STATUS INDICATOR
An LED charge status indicator is provided both with and without the optional digital display. Indicator function is
identical for the SB3048, SB3048D, and SB50RD.
CHARGE STATUS INDICATOR
INDICATOR
ACTION
CHARGE
MODE
TYPICAL BATTERY STATE
OF CHARGE
OFF
CHARGE OFF
(NO PV OR OVER TEMP.)
NOT DISPLAYED
CONTINUOUSLY ON
BULK
LESS THAN 70% FULL
BLINKING
2 SEC ON / 2 SEC OFF
ACCEPTANCE
BETWEEN 70% - 95% FULL
BLINKING
0.2 SEC ON / 2 SEC OFF
FLOAT
FULLY CHARGED
BLINKING RAPIDLY
0.2 SEC ON / 0.2 SEC OFF
EQUALIZE
N/A
TABLE 1
THREE STAGE CHARGE CONTROL
Solar Boost 3048 is typically configured for a three stage charging process. Acceptance and float voltages are
factory set to approximately 28.6/57.2 volts and 26.6/53.2 volts respectively, which are appropriate for a liquid
electrolyte lead-acid battery at 80
°
F. As described in the installation section, the most highly optimized charge process
is obtained by using the optional SensorLug battery temperature sensor, and if battery load varies during charge, an
optional external current shunt to determine full charge based on net battery charge current.
Bulk Charge
During the bulk charge stage, the charge status LED will be on continuously. Solar Boost 3048 delivers as much
charge current as possible during bulk to rapidly recharge the battery. In the bulk stage, the battery is typically at a
low state of charge of less than 70% full. Bulk charge is initiated when; 1) Charge current during acceptance or float
increases above the Float Transition Current, or 2) Insufficient power is available from the PV array to hold the battery
at the desired acceptance or float voltage. Maximum available charge current during bulk varies with the number and
size of PV modules installed, available solar energy, and operation of the proprietary MPPT current boosting
system. Electronic current limit prevents the possibility of overload by limiting output current to 30 amps regardless
of available PV input current or input power.
Acceptance Charge
Following bulk charge, the system changes to a constant voltage mode where the acceptance voltage is applied to
the battery. In the acceptance stage, the battery is typically at a high state of charge of between 70% to 95% full.
With installation of the optional SensorLug battery temperature sensor, the acceptance voltage continuously adjusts
to the optimum value based on battery temperature. The graph of Figure 2 shows acceptance voltage as a function of
battery temperature for the factory setpoint of 28.6/57.2 volts @ 80
°
F. Charge current slowly decreases as the battery
continues to charge at the acceptance voltage. When charge current during acceptance decreases to the Float
Transition Current, typically set to 1.0 amps per 100 amp-hours of battery capacity, the battery is fully charged without
being over charged and the system switches to float.
