Samlex America SEC-2425UL - Manuel (Page 13)

12 | SAMLEX AMERICA INC. SAMLEX AMERICA INC. | 13
seCtIOn 4 | Principle of Operation
28V / 28.8V at both the charger and battery terminals is the constant Absorption Volt-
age being put out by the charger. The intrinsic voltage of the battery is still lower than
this voltage as the battery is still not fully charged at this transition). As the intrinsic
voltage of the battery rises further, the charging current starts tapering down (section
D2 to E2). 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.
When the 4 Hr / 8 Hr Timer runs out or when the charging current tapers down to 10%
of the rated capacity of the charger (5A +/- 0.5A for SEC-1250UL and 3A +/- 0.5A for SEC-
2425UL) at point “E2” (whichever is earlier), the charger transitions to the next Stage 3
- Constant Voltage, Float or Maintenance Charge Stage (“U” Phase)
note: The threshold of current for change-over between the Constant Overcharge Volt-
age, Timed Voltage Absorption / Boost Stage (“U0” Phase) & the Float / Maintenance
Charge Mode (“U” Phase) are different as follows:
Sec-1250Ul Sec-2425UL
From “Uo” Phase to “U” Phase 5A +/- 0.5A 3A +/- 0.5A
From “U” Phase to “Uo” Phase 10A +/- 1A 6A +/- 1A
charging characteristics during this Stage Are As Follows:
• The Absorption Stage (“U
o
” Phase) feeds additional 35% to 55% of the capacity that
adds up to a total charged capacity of around 115% to take care of around 15% loss
of charging efficiency.
• Orange LED marked “U
o
” Phase on the optional Remote Control 900-RC will be lit
StAGe 3 - conStAnt VoltAGe, FloAt oR MAintenAnce
cHARGe StAGe (U PHASe)
During this mode, the charger outputs a constant voltage "U" = 13.5V (SEC-1250UL) or
27V (SEC- 2425UL). This helps in maintaining full capacity of the battery and also pro-
vides replacement charge to overcome self discharge of the battery. The battery
can remain connected in this stage indefinitely without the risk of discharging.
charging characteristics during this stage are as follows:
Green LED marked Float Stage (“U” Phase) on the optional Remote Control
900-RC will be lit.