14 | SAMLEX AMERICA INC.
SeCtIOn 6 |
Operation
cHARGinG AnD BAcKUP oPeRAtion
Charging current will be proportional to the discharged state of the battery and is lim-
ited to maximum of 4A when the battery is completely discharged (Standing Voltage of
11.4V). The current will taper down from 4A as the battery gets charged and its voltage
rises. When the battery is fully charged, the current will drop down to 0.1% of the Ah
capacity of the battery to compensate for self-discharge. When fully charged, the volt-
age at the Battery Terminals (5, 6) will be the float Voltage of 13.8V ± 0.2V.
Battery should not be charged at very high current. Normally, as a rule of Thumb, the
maximum charging current should be limited to 10% of the Ah capacity at 20 Hour rate
unless higher current is allowed by the manufacturer. Higher charging current produces
higher heating, which reduces the life of the battery. further, higher charging current
will not re-charge the battery to full 100% capacity unless the Absorption Voltage is
increased proportionately. This may not be possible with chargers that do not have pro-
grammable charging voltages. It is, therefore, recommended that the capacity of the
battery used with this unit should be in the range of 40 to 100Ah which is appropriate
for 4A charging current.
The voltage seen at the Battery Terminals (5, 6) will be the actual terminal voltage of the
battery (assuming no voltage drop in the battery cables) and will be proportional to its
State of Charge. When the battery is fully charged, the voltage at the Battery Terminals
(5, 6) will approach13.8V ± 0.2V.
If AC input power fails, the DC load(s) will be instantaneously transferred to the external
12V backup battery and the battery will start discharging. When the battery is supplying
the load, the voltage seen at the Load Terminals will be 0.3V ± 0.2V less than the voltage
at the Battery Terminals. When AC input power is restored, the DC load will once again
be transferred instantaneously to the Power Supply Section and the external backup
battery will be recharged and kept in charged condition all the time at float Voltage of
13.8V ± 0.2V.
SURGe PoWeR cAPABiLitY in Dc UPS BAtteRY BAcKUP MoDe
When operating in DC UPS Battery Backup Mode (external 12V battery is connected),
the unit is capable of providing short term surge current of up to 50A for < 1 sec (ex-
ternal 25A fuse on the load side will not blow for this short duration). Maximum 25A
will be provided by the Power Supply Section and balance 25A will be supplied by the
battery. During the period of this short term overload, the voltage seen by the load will
be = (battery voltage – 0.3V± 0.2V).
oPeRAtion AS noRMAL PoWeR SUPPLY WitHoUt eXteRnAL BAtteRY
If battery backup function is not used (external backup battery is not connected), the
unit will work as a normal power supply with ability to supply 23A continuous at 13.8V
± 0.2VDC at the Load Terminals (3, 4). The maximum overload current will be limited to
25A. Under overload conditions, the output voltage will not be regulated and will drop.
