Specialty Concepts SC3/20 - Manual (Page 16)

O P T I O N S
The following are instructions for installing and using the options that are available on the SC3/20.
These options must be specified at the time of an order; options can not be added to finished
units.
OPTION A - Temperature Compensation:
DESCRIPTION: On units equipped with temperature compensation, a small sensor on a ten
foot cable 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). Systems with other sources of charging,
(alternators on RVs) or applications where the battery is on maintenance charge, normally
do not need this option.
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 rubber-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.
OPTION E - Low-Voltage Load Disconnect (LVD):
This option provides a relay that can be used as a switch to automatically disconnect loads at
a low-voltage condition of the battery. Two additional wires are provided for connection to the
Battery (+) and Load (+). Refer to Figure 2: SC3/20 with E-OPTION (LVD)
The relay activates at about 11.5 volts and deactivates at about 13.0 volts. The “LOW
VOLTAGE” light will go on to indicate the LVD. To install this option, choose either white wire
and connect it to the Battery (+) and connect the remaining white wire to the Load (+). Connect
the Load (-) to Battery (-) terminal.