SamplexPower SEC-1250UL Guide D'utilisation page 14

SECTION 4 |
"C2" (Current Curve in Figs 4.1 and 4.2), the charger transitions to Absorption Stage
Level 2 (See Section 4.3.2.3.2)
4.3.2.3.2 Absorption Stage Level 2: After completion of Absorption Stage Level 1 (Sec-
tion 4.3.2.3.1), the Absorption Voltage is raised to Level 2 as follows:
i. SEC-1250UL:
o Absorption Voltage is raised from 13.5V to 14.4V for Flooded /AGM or,
o Absorption Voltage is raised from 13.5V to 14.0V for Gel Cell
NOTE: The desired voltage is selected through DIP Switches S1 and S2 (See Section 7.4
and Table 7.1).
ii. SEC-2425UL:
o Absorption Voltage is raised from 27.0V to 28.8V for Flooded /AGM or,
o Absorption Voltage is raised from 27.0V to 28.0V for Gel Cell
NOTE: The desired voltage is selected through DIP Switches S1 and S2 (See Section
7.4 and Table 7.2).
At voltage transition point "C1" (Voltage Curve in Fig 4.1 and Fig 4.2), the internal out-
put voltage of the charger will be raised from (i) 13.5 V to 14.0 / 14.4V for SEC-1250UL
or, (ii) from 27.0V to 28.0 / 28.8V for SEC-2425UL.
However, this increased voltage will not be seen as constant voltage immediately
(Section C1 to D1 in Voltage Curves in Figs 4.1 and 4.2 shows voltage becomes constant
only after point D1) because the battery will try to draw current higher than the Bulk
Stage Current rating of the charger (50A for SEC-1250UL or, 25A for SEC-2425UL) due
to sudden rise in voltage of the charger. The charger will deliver current limited to the
rated Bulk Stage Current (Section "C2-D2" in the Current Curves in Figs 4.1 and 4.2),
its voltage will drop due to loss of regulation due to "current limit condition" and will
get clamped to the intrinsic (internal) battery voltage. The battery will start charging
further at the rated Bulk Stage Current (Section C2 to D2 in the Current Curves in Figs
4.1 and 4.2) and its voltage will start rising (Section C1 to D1 in Voltage Curves in Figs
4.1 and 4.2). At point "D2" (Current Curves in Figs 4.1 and 4.2), the charging current will
reduce to less than the Bulk Stage Current limit value of 50A for SEC-1250UL / 25A for
SEC-2425UL and the charger will then exit the current limited constant current mode
and will enter constant voltage mode of 14V/14.4 V for SEC-1250UL or, 28.0 / 28.8V for
SEC-2425UL. (Please note that voltage of 14V/14.4 V for SEC-1250UL or, 28.0 / 28.8V for
SEC-2425UL is the constant Absorption Voltage Level 2 being put out by the charger.
The intrinsic (internal) voltage of the battery will still be lower than these voltages
because the battery will still not be fully charged at this transition). As the intrinsic
(internal) voltage of the battery rises further, the charging current will start tapering
down (Section D2 to E2 in the Current Curves in Figs 4.1 and 4.2). Tapering charge is
provided at this transition to reduce surface charge effect to ensure that the charge
slowly diffuses to the internal thickness of the plates and prevents overcharging.
The charger will transition to the next "Stage 3- Float Stage" (Section 4.3.3) at point
"E2" (Current Curves in Figs 4.1 and 4.2) under the following 2 conditions (whichever
14 | SAMLEX AMERICA INC.
Principles of Operation