Specialty Concepts SC3/20 - Manual (Page 18)

8. BAD CONNECTION: PANEL - This may include problems with the connections to the
SC3/20 (yellow wire and green wire), at either array terminals (“+” or “-”) or in fuses and
crimp connectors in these lines.
9. BAD CONNECTION: BATTERY - This may include a blown fuse at the front of the SC3/20
(See CONTROLLER FUSE BLOWN below). A bad battery connection could also be caused
be a defective fuse, a bad fuse holder or problems with the connections in the system. Bad
connections can be found at the SC3/20 (red wire and black wire), at either battery terminal
or in fuses and crimp connectors in these lines.
10. CONTROLLER FUSE BLOWN - The fuse on the front panel of the controller can be blown
and may need replacing. Replacement is a 20 amp AGC fuse. Before replacing a blown
fuse, locate and correct the cause.
Possible causes for blown fuses: 1) Reverse battery connection
2) Incorrect connection
3) Array current is over 20 amps
11. INCORRECT VOLTAGE SET-POINT - The SC3/20 may be functional but the charge
termination set-point may not be correct for your batteries. The factory set-point is around
14.3 volts and is designed to work for the majority of batteries. Set the front panel switch
position to “C”. At times of mild temperature (“room temperature”) the display should read
-142 to -144 (indicating 14.2 to 14.4 volts). If the reading is outside of this range, an
adjustment may be necessary. Refer to the ‘CHARGE SET-POINT ADJUSTMENT” section.
Adjustments to the calibration should be performed by qualified personnel or at the factory.
12. SYSTEM NOISE - The SC3/20 can be subjected to electrical noise from a converter or
inverter. This will cause the meter readings to be erratic. If the SC3/20 is connected to the
converter, or to a buss that is connected to a converter, try connecting the SC3/20 directly to
the battery instead.
Fuse Removal Test
This test temporarily removes the battery connection to the SC3/20. By noting the reaction on the
SC3/20’s volt-meter, one can receive additional information about the workings of your system.
First, during a sunny period, observe "BATTERY VOLTAGE" reading (it must be over 10 volts to
perform this test). Then, remove the fuse, observe the "BATTERY VOLTAGE" reading again. Note
the new reading and any changes and refer to the sections below.
NOTE: When the fuse is removed, it is normal for the “CHARGING” and the “CHARGED” lights to both
go on (during the daytime) and to hear a faint buzzing. Remember to replace the fuse after testing.
“BATTERY VOLTAGE” READING IS BLANK - If the meter is blank, this means that the solar array is
bad or disconnected or that the SC3/20 is defective. Check the SOLAR PANEL PROBLEMS
section below before returning the SC3/20 for repair.
VOLTAGE READING STAYS THE SAME - If the meter stays the same before and after removing the
fuse, that means that the controller may not be connected to the battery. See above Help Note #9 -
BAD CONNECTION: BATTERY before returning the controller for repair.
VOLTAGE MOVES HIGHER, READS FROM 12.0 TO 14.7 - This is the correct reaction and the unit
is working properly.
VOLTAGE READING IS HIGH (GREATER THAN 16.0 VOLTS) - This means that the meter is trying to
show the panel voltage, which is usually about 16-22 volts for a 12 volt panel. This would indicate
that the SC3/20 is defective.
BUZZING - There may be a “buzzing” sound or high pitched whine from the controller. This is normal
and is caused by the controller rapidly switching on and off while not connected to the battery.