Samlexpower SEC-1245A Owner's Manual - page 19
REDUCTION OF MAXIMUM CHARGING CAPACITY TO HALF TO CHARGE
LOWER CAPACITY BATTERIES
Batteries should not be charged at very high currents to ensure long life. Normally, the
maximum charging current should be limited to approximately C/5 (where C is the AH
capacity of the battery at 20 hour rate). Thus, at the rated current capacities (45 A for SEC-
1245A and 25 A for SEC-2425A), the minimum AH capacity of the battery that should be
charged with the charger will be:
•
45 A x 5 = 225 AH for SEC-1245A
•
25 A x 5 = 125 AH for SEC-2425A
Thus, SEC-1245A should be used to charge battery with AH capacity > 225 AH and SEC-
2425A should be used to charge battery with AH capacity > 125 AH.
A provision has been made to reduce the maximum charging current to approximately half:
22.5 A +/- 1 A for SEC-1245A & 12.5 A +/- 1 A for SEC-2425A. This mode is termed as “Half
Power Mode”. This mode can be selected by pressing push switch (7) marked “Half Power
Mode”. When selected, a Green LED (8) marked “Half Power” will be lighted. When “Half
Power Mode” is selected, batteries with the following minimum capacities can be charged:
•
SEC-1245A - 100 AH and above
•
SEC-2425A - 55 AH and above
TEMPERATURE COMPENSATION
The cell voltages of a battery depend upon the temperature of the cells inside the battery. The
cells have a negative temperature coefficient – their voltage levels increase at lower tempera-
ture and decrease at higher temperature. The negative temperature coefficient is – 2.8 mV / º
F / cell or - 16.8 mV / º F/ 6 cells for a 12 V battery or - 33.6 mV / º F / 12 cells for a 24 V
battery.
The battery and battery charger voltages are normally specified at a temperature of 80 º F
(26.7 º C). Thus, if the battery temperature is considerably lower than or higher than 80 º F,
it will be under-charged or over-charged unless the battery charger has temperature compen-
sation.
TEMPERATURE SENSOR PROBE TF-500
This charger has a provision for temperature compensation. A temperature sensor unit -
Model No. TF-500 (16, 17) is provided for this purpose.
CAUTION!
This temperature sensor is matched and calibrated for each battery charger
and should not be interchanged with the sensor from another battery charger.
The temperature sensor comes with 5 Metre cable. It has a plug (17) on one end. Connect
this plug into the jack marked TS (12) on the rear panel of the charger. The other end has
the temperature sensor element (16). Mount this temperature sensor element flush with
the top surface of the battery for proper heat transfer.
When the temperature sensor is connected, the voltages during Stage 2 and Stage 3 are
automatically adjusted as per the temperature of the battery and the above temperature
coefficient.
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