Specialty Concepts SCS/90 - Manual (Page 9)

TEMPERATURE COMPENSATION
DESCRIPTION: - The SCS has a small sensor on a ten foot cable that is wired into
the controller to adjust the charging thresholds according to battery temperature.
The rate of compensation is -5mv/
°
C per battery cell in series from 25
°
C.
WHEN NEEDED: - Temperature compensation is recommended for stand alone
systems with sealed batteries, or for systems that have no regular charging
source other than PV AND where prolonged temperature extremes will be
experienced during periods of charging. Temperature extremes would be when
the battery will be exposed to average temperatures below 50
°
F (10
°
C) or above
90
°
F (32
°
C).
CAUTION: SENSOR CABLE: If the sensor is damaged or the cable is cut, the
controller will no longer function.
INSTALLATION INSTRUCTIONS
Provision must be made to attach the sensor unit to the battery. This must be done
properly to insure that accurate temperature readings are made. It is important that
ambient temperature not influence the sensor. To minimize this, attach the sensor to
the battery as follows:
1. RUN SENSOR TO BATTERIES: Run the sensor to the batteries, taking care to
prevent damage to the actual sensor itself. When pulling the sensor through
conduit, do not pull on the plastic-coated sensor, but instead on the gray cable
just behind the sensor. Do not force the sensor. The sensor itself is made of
glass, but it is encased in an aluminum tube, then coated with plastic. If the tube
should pull off of the glass sensor, and if the sensor is not damaged, the tube
can be slipped back over the sensor.
2. ATTACH SENSOR: Use the adhesive sided foam pad (included) to cover the
sensor (the plastic coated unit at the end of the cable) and attach it to the side
of the battery approximately half-way up the side of the battery. Choose a
battery that is shielded from drafts or sunlight by other batteries or by the
battery shelter. DO NOT immerse the sensor directly in the battery's electrolyte,
it will be severely damaged. Temperature compensation of charging voltage is
now automatic.
DAMAGED SENSOR: If the sensor is damaged or lost, the controller will no longer
function. By adding a 4.7 K
Ω
resistor, the temperature sensor feature can be
removed from the unit and the unit will operate without temperature compensation.
Table 1 : Voltage change in charging set-points by temperature
CONTROLLER TEMPERATURE
°°
C (
°°
F)
VOLTAGE 0 (32) 10 (50) 20 (68) 25 (77) 30 (86) 40 (104) 50 (122)
12 VOLT + .75 + .45 + .15 0 -.15 - .45 - .75
24 VOLT + 1.50 + .90 + .30 0 -.30 - .90 -1.50
36 VOLT + 2.25 + 1.35 + .45 0 -.45 -1.35 -2.25
48 VOLT + 3.00 + 1.80 + .60 0 -.60 -1.80 -3.00