SamplexPower SEC-1250UL Guide D'utilisation page 25

SECTION 7 | Preparing the Charger for Operation
7.6 REDUCTION OF MAXIMUM CHARGING CAPACITY TO HALF FOR
SAFE CHARGING OF LOWER CAPACITY BATTERIES - HALF POWER
MODE
Batteries should not be charged at very high currents to ensure long life. Unless ap-
proved by the manufacturer, the maximum charging current should be limited to
approximately C/10 (where C is the Ah capacity of the battery at 20 Hour Rate). Thus, at
the rated Bulk Stage Current capacities (50A for SEC- 1250UL and 25A for SEC-2425UL),
the Ah capacity of the battery that should be charged with the charger will be:
• 50A x 10 = 500 Ah for SEC-1250UL
• 25A x 10 = 250 Ah for SEC-2425UL
If battery with lower Ah capacity is charged at the full charging rate, the battery life is
likely to be reduced.
A provision has been made to reduce the maximum charging current to approximately
half: 25A +/- 1A for SEC-1250UL & 12.5A +/- 1A for SEC-2425UL. This mode is termed as
"Half Power Mode". This mode can be selected by pressing push switch marked "Half
Power Mode" (8 in Fig 3). When selected, a Green LED marked "Half On" (5 in Fig 3)
will be lighted. When "Half Power Mode" is selected, batteries with the following lower
capacities can be safely charged at C/10 charging rate:
• SEC-1250UL - 250 Ah
• SEC-2425UL - 125 Ah
7.7 BATTERY TEMPERATURE COMPENSATION
The cell voltages of a battery depend upon the temperature of the cells inside the bat-
tery. The cells have a Negative Temperature Coefficient - their voltage levels increase
at lower temperature and decrease at higher temperature. The Negative Temperature
Coefficient is - 28 mV / ºC for SEC-1250UL & - 56 mV / ºC for SEC-2425UL.
The battery and battery charger voltages are normally specified at a temperature of
77ºF / 25ºC. Thus, if the battery temperature is considerably lower than or higher than
77ºF / 25ºC, it will be under-charged or over-charged unless the battery charger has
temperature compensation.
7.8 BATTERY TEMPERATURE SENSOR MODEL TF-500
Battery Temperature Sensor Model TF-500 (14, Fig 3) has been provided with the unit. It
comes with 5M long cable. It has an adhesive backed Temperature Sensing Element (14A,
Fig 3.1) on one end and 3.5 mm diameter Plug (14B, Fig 3) on the other end.
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