Samlexpower SEC-1260A Owner's Manual page 21

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 (60 A for SEC-
1260A, 80 A for SEC-1280A and 40 A for SEC-2440A), the minimum AH capacity of the
battery that should be charged with the charger will be:
•
60 A x 5 = 300 AH for SEC-1260A
•
80 A x 5 = 400 AH for SEC-1280A
•
40 A x 5 = 200 AH for SEC-2440A
Thus, SEC-1260A should be used to charge battery with AH capacity > 300 AH, SEC-
1280A should be used to charge battery with AH capacity > 400 AH and SEC-2440A should
be used to charge battery with AH capacity > 200 AH.
A provision has been made to reduce the maximum charging current to approximately half: 30
A +/- 1 A for SEC-1260A, 40 A +/- 1 A for SEC-1280A & 20 A +/- 1 A for SEC-2440A. 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-1260A - 150 AH and above
•
SEC-1280A - 200 AH and above
•
SEC-2440A - 100 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 temperature
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 compensation.
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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