Specialty Concepts SC3/20 - Manual (Page 20)

SC3/20 PROBLEM CASES (from SC3/20 PROBLEMS chart)
SC3/20 Case 1 - Check the battery voltage. Minimum operating voltage for the display is about 10 volts. If the
battery voltage is over 10 volts then this condition indicates that a bad connection exists to both the battery (See
BAD CONNECTION: BATTERY (Help Note #9)) and the solar panel (See BAD CONNECTION: PANEL (Help
Note #8)) or that the SC3/20 is defective.
SC3/20 Case 2: - This condition usually indicates a bad connection exists to the battery (See BAD CONNECTION:
BATTERY (Help Note #9)). This could also be caused by a blocking diode or diode isolator in the battery
connection (red wire line). If there is a blocking diode, remove it. If there is a diode isolator, modify the system so
the SC3/20 charges only one battery bank.
SC3/20 Case 3 - This indicates that the system has no panel input, or the SC3/20 charge set-point has been
modified or the unit is defective. Perform the FUSE REMOVAL TEST (above). If the volt reading remains
unchanged, then the unit may be out of calibration (See INCORRECT VOLTAGE SET-POINT (Help Note #11)).
If the voltage display goes blank, there is either a bad panel connection (See BAD CONNECTION: PANEL (Help
Note #8)) or the unit is defective.
SC3/20 Case 4 - This is a result of a bad battery connection. (Help Note #9).
SC3/20 Case 5 - If the charge light is on with 0 amps on the array current reading, then this could indicate a condition
of low light to the panels, a system problem or a controller problem. Perform the FUSE REMOVAL TEST
(above). If the voltage changes a little, then the controller seems to be working OK and the panels are charging a
small amount. If the voltage does not change, refer to BAD CONNECTION: BATTERY (Help Note #9). If the
voltage reading is 16-22 volts, this would indicate a defective controller. If the meter does something else, then
suspect a bad connection somewhere or another system problem.
SC3/20 Case 6 - There are several possibilities for this. See BAD CONNECTION: BATTERY (Help Note #9),
INCORRECT VOLTAGE SET-POINT (Help Note #11), or the unit can be defective. Perform the FUSE
REMOVAL TEST (above). If the voltage goes up a little, the unit is functional but may be set for an incorrect
voltage. If the voltage meter remains unchanged, this suggests there is a problem with the battery connection. If
the voltage reading is 16-22 volts, the unit is defective.
SC3/20 Case 7 - The "CHARGING" light can be on very dimly at night if the panels are under even very low levels of
light (moonlight or street lights). If "CHARGING" light is on brightly at night, the controller is miswired or defective
or there is a blocking diode located within the solar panels or in the panel connection. TEST: Disconnect the panel
(yellow wire), if the light goes off, then this would indicate that there is not a serious problem; either the panel is
receiving enough light for a slight charge or there is a diode in the panel connection causing the light to be on. If
the light stays on, this suggests that the SC3/20 may be defective.
SC3/20 Case 8 - See INCORRECT VOLTAGE SET-POINT (Help Note #11) or the unit is defective.
SC3/20 Case 9 - This can be a normal condition or can indicate a bad battery. See PROBLEMS WITH BATTERIES
(Help note 7) or BAD CONNECTION: BATTERY (Help Note #9). TEST: Take a voltage reading at the battery
with an accurate meter. If the voltage reading stays steady
while the voltage reading on the controller is going up
and down, then suspect a bad battery connection. If the voltage here also moves up and down rapidly, this would
suggest the battery bank is bad or too small, or this may be a normal condition. When the battery is charged up,
and the array can provide lots of charge current, the controller can pulse on and off rapidly, particularly when
there is current being used by a load. This is a normal operating condition and is not a problem.
SC3/20 Case 10 - This is a result of SYSTEM NOISE (Help Note #12)
SC3/20 Case 11 - This can be a result a BAD CONNECTION: BATTERY (Help Note #9). The battery connection
problem could be in the nature of corrosion, or a loose connection. TEST: Check the system at night or
disconnect the yellow wire. If the difference goes away, suspect a bad connection or corrosion in the battery
connection.
SC3/20 Case 12 - Refer to the Solar Panel Problems section for a list of potential problems. Also, check to see that
there is not an alternative path from the solar panel negative to the battery negative other than through the
SC3/20.
SC3/20 Case 13 - The charge control circuit will reset when power is removed. Pushing or removing the front panel
fuse will momentarily cause power to be lost to the control circuit, causing it to reset. It may reset in the charging
or non-charging mode, but most often in the charging mode. This is normal and does not indicate a problem.
SC3/20 Case 14 - The buzzing sound is caused by the controller rapidly switching on and off and is a problem
relating to a BAD CONNECTION: BATTERY (Help Note #9).
SC3/20 Case 15 - The SC3/20 may get warm during normal operation, but not hot. If the unit should get too hot to
touch, consider it defective.