Specialty Concepts SC3/20 - Manual (Page 4)

R E L A T E D S Y S T E M E Q U I P M E N T
The SC3/20 is an integral part of a solar electric power system that includes a PV solar array,
a battery and a load. These items should be installed in accordance with the National
Electrical Code, and with the instructions provided by the equipment supplier.
SOLAR ARRAY PANELS: The SC3/20 is compatible with all makes and models of PV panels,
provided the open circuit voltage (Voc) does not exceed 26 volts and the short circuit
current (Isc) of the array does not exceed 20 amps.
BATTERIES: The SC3/20 is calibrated for proper charging of standard batteries that are
normally used in recreational vehicles, boats, and remote stand alone systems. These
include wet cell batteries (with filler caps) and the sealed, maintenance-free batteries. A
battery disconnect switch should be installed on the Battery (+) run to the controller. This
will allow a safe way to disconnect the battery during installation.
TWO-BATTERY SYSTEMS & SYSTEMS WITH BATTERY ISOLATORS : If solar charging
of two separate batteries is desired, a switch can be installed to allow manual selection of
one battery or the other. In installations that use a diode battery isolator with two batteries,
the SC3/20 can be connected to one of the outputs from the isolator, or at one of the
batteries itself to charge that battery only. Do not connect the SC3/20 to the input of the
isolator, the SC3/20 will not operate properly when charging batteries through a diode.
LOADS: System loads such as lights, radios and DC/AC inverters must be 12 volts DC (unless
an inverter is being used). The loads should be fused as recommended and connected
directly to the battery or to a load center/circuit breaker box. See the diagrams in the
"INSTALLATION" section.
OTHER CHARGING SOURCES: The SC3/20 can be used only as a photovoltaic (solar)
charge controller. DO NOT use the SC3/20 to regulate other power sources , such as a
hydro or wind generator/alternator or an AC battery charger. This could result in damage to
the SC3/20 and/or the generating equipment
The SC3/20 CAN remain connected to a battery that is also being charged by an another
source (alternator, battery charger, etc.) without damage to the SC3/20 or to the solar
panels. Connect all other charging sources, with their own charge regulation devices,
directly to the battery. No isolation diode or transfer switch is required. NOTE: Some
battery chargers or converters powered by 110 volt sources are not properly regulated and
can overcharge batteries if left unattended.