SPECIALTY CONCEPTS MODEL 1
SC1
(
Photovoltaic Battery Charge Controller
Installation and Operation Manual
SPECIALTY CONCEPTS, INC.
8954 Mason Ave.
Chatsworth, CA 91311 USA
Copyright 8 / 1997 Specialty Concepts, Inc.
GENERAL DESCRIPTION
)
The SPECIALTY CONCEPTS CHARGER MODEL 1 (SC1) is a versatile, industrial quality charge
controller for the efficient use of photovoltaic energy and the protection of expensive batteries. It
is available for 12, 24, 36, and 48 volt negative ground systems with models for 30 amps of
charge current (optional 50 amps available) .
The SC1 consists of a series-relay battery charge controller in a wall mount chassis with low
voltage load disconnect, a load circuit breaker, and system status lights. The lights indicate
"CHARGE MODE" and "LOAD DISCONNECTED" conditions. The SC1 is housed in an anodized
aluminum chassis and has a terminal block that accepts up to 10 gauge wire. A terminal adapter
kit is included to increase wire size to #6.
FEATURES
CHARGE REGULATION
•30 amp charge current, 12, 24, 36 or 48 volt
•50 amp charge current (optional), 12 or 24 volt
•Two-step, series charging, 12,24 v
•Single step, series charging, 36,48 v
•Adjustable charging set-points (option)
•Temperature compensation (option)
LOW-VOLTAGE LOAD DISCONNECT (LVD)
•30 amp LVD, 12 volt
•20 amp LVD, 24 volt
•15 amp LVD, 36 and 48 volt
•Adjustable disconnect set-points
•Manual override switch
DESIGN FEATURES
•Maximum array usage
•Over-current protection - load circuit breaker
•Reverse polarity protection
•Reverse leakage protection
•Lightning protection
•Input noise suppression
•Remote battery voltage sense
MONITORING and MOUNTING
•“CHARGE MODE” light
•”LOAD DISCONNECTED” light
•Analog volt/amp meters (option)
•Indoor wall mount
•Outdoor enclosure (accessory)
SPECIFICATIONS
PARAMETERS UNITS NOMINAL VOLTAGES
12 v 24 v 36 v 48 v
Charge Current, Continuous (1) (Amps) 30 30 30 30
Charge Current, Max (60 seconds) (2) (Amps) 39 39 39 39
Load Current, Continuous (3) (Amps) 30 20 15 15
Load Current, Max (60 seconds) (2) (Amps) 39 26 20 20
Array Voltage, Max Voc (Volts) 22 44 66 88
Operating Voltage @ Battery, Minimum (Volts) 8.5 17.0 25.5
34.0
Quiescent Current (4) (Milliamps) 10 10 10 10
Current Consumption, Charging (5) (Milliamps) 160 160 80 80
Current Consumption,
Load Disconnected (6) (Milliamps) 140 100 70 70
Current Consumption, Metering, Typ. (7) (Milliamps) . 5 .5 .5 .5
Voltage Drop, Typ. (Array to Battery) (Volts @ Max rating) .15 .15 .15 .15
Voltage Drop, Typ. (Battery to Load) (Volts @ Max rating) .40 .40 .40 .40
Full Charge Termination (8) (Volts) 14.8 + .2 29.6 + .4 44.4 + .6 59.2 + .8
Full Charge Resumption (Volts) 12.8 + .2 25.6 + .4 38.4 + .6 51.2 + .8
Load Disconnect (9) (Volts) 11.5 + .2 23.0 + .4 34.5 + .6 46.0 + .8
Load Disconnect Adjustment Range (Volts) 11.0 to 12.0 22.0 to 24.0 33.0 to 36.0 44.0 to 48.0
Load Reconnect (Volts) 13.0 + .3 26.0 + .6 39.0 + .9 52.0 + 1.2
Float Voltage (Volts) 14.1 + .2 28.2 + .4 NA NA
Float Current, Max (Amps) 3 1 NA NA
Temp. Compensation coef. (from 25°C) (10) (Volts/°C) -.03 -.06 -.09 -.12
Operating Temp. Range (°C) 0 to 50 0 to 50 0 to 50 0 to 50
Storage Temp. Range (°C) -55 to 85 -55 to 85 -55 to 85 -55 to 85
Notes:
(1) 50 amp option available.
(2) Carry only, Non-switching
(3) Non-inductive.
(4) Both relays unenergized, red L.E.D.s off, typical value.
(5) Charge relay energized, red L.E.D. on, typical value.
(6) LVD relay energized, red L.E.D. on, typical value.
(7) Metering option
(8) Adjustable set-point is available. Refer to table.
PART NUMBERING KEY
EXAMPLE: Model
SC1 - 12 - AF
NOMINAL
MODEL VOLTAGE OPTIONS
SC1 12 A - Remote Temperature Compensation
24 F - Volt Meter / Amp Meter
36 P - 50 Amp charge current (12 & 24 volt)
48 T - Adjustable Full Charge Termination Set-point
FULL CHARGE TERMINATION SET- POINTS (OPTION)
Control SWITCH POSITIONS
Voltage A B C D
12 15.3 14.8 14.3 13.8
24 30.6 29.6 28.6 27.6
36 45.9 44.4 42.9 41.4
48 61.2 59.2 57.2 55.2
Nominal Voltage
Options
ACCESSORIES
INDOOR ENCLOSURE (NEMA 13)
OUTDOOR ENCLOSURE (NEMA 4X)
Specifications and product availability subject to change without notice.
RELATED SYSTEM EQUIPMENT
The SC1 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 SC1 is compatible with all makes and models of PV panels. The
open circuit voltage of the array should not exceed the maximum open circuit voltage of the
SC1(See SPECIFICATIONS: “Array Voltage, Max Voc”) and the maximum power current of
the panels should not exceed 30 amps (or 50 amps with P-Option).
HIGHER CHARGING CURRENTS: For arrays exceeding the maximum power current of the
SC1, the array can be divided into smaller parallel sub-arrays. A SC1 can be wired in parallel
to each sub-array, provided the sub-arrays do not exceed the rating of the individual SC1.
BATTERIES: The standard SC1 is designed to be used with the most common lead-acid
batteries. These are wet cell batteries using pure lead, lead antinomy and/or lead calcium
grids. Adjustments in voltage set-points may be made on SC1 models with the adjustable setpoint option (Option T). For sealed, maintenance free batteries, or vented pocket plate nickelcadmium batteries, the charging set-points should be adjusted to maximize performance and
battery life. For sealed, maintenance free batteries or nickel cadmium batteries, consult the
battery manufacturer for recommended set-points and refer to Table 1 (OPTIONS section) for
appropriate settings.
LOADS: The load is considered the item or equipment that the PV system is powering. System
loads such as lights, radios, DC/AC inverters, etc. must be rated for the proper DC input
voltage. DC loads not exceeding the rated SC1 load current (See SPECIFICATIONS “Load
Current, Continuous”) can be connected to the load terminals of the SC1 and they will
automatically be disconnected in the event of a low-voltage condition. Higher current, or
inductive loads such as pumps, motors or inverters should be connected directly to the
battery, using properly rated over-current protection devices (fuses or circuit breakers).
OTHER CHARGING SOURCES: Do not use the SC1 to regulate a power source other than a
photovoltaic array, such as a hydro or wind generator/alternator or an AC battery charger.
This could result in damage to the SC1 and/or the generating equipment. Connect other
charging sources with their own regulation devices directly to the battery, using properly rated
over-current protection devices.
The SC1 and solar panel can remain connected to a battery being charged by other sources,
(alternator, battery charger, etc.) without damage to the controller or solar panel.
INSTALLATION
WARNINGS / CAUTIONS
WARNING: Electricity, even low-voltage electricity, can be dangerous. Installation should be
performed by a licensed electrical contractor or other qualified personnel only. The
requirements of the U.S. National Electrical Code should be followed.
WARNING: Follow all safety precautions of the battery manufacturer. Proper ventilation must be
provided for vented batteries. Most vented batteries produce hydrogen gas when charging,
which is extremely explosive. DO NOT expose the battery to open flame, matches, cigarettes
or sparks.
WARNING: Install properly DC rated, high interrupt current limiting over-current protection and
disconnect equipment between the SC1 and the battery. Suitable fused disconnect switches
are low cost and provide protection from fire and damage due to over-current. Refer to the
National Electrical Code or your local alternative energy vendor for recommendations.
CAUTION: DO NOT subject the controller to voltages greater than the "Array Voltage, Max Voc"
as stated in the SC1 specifications. This is the open circuit voltage (Voc) of the solar panel, or
the sum of the open circuit voltages of all modules connected in series.
CAUTION: DO NOT exceed the maximum current rating ("Charge Current, Max") of 30 amps (or
50 amps with P-Option). This is the sum of the maximum power currents of all the modules in
parallel.
CAUTION: On higher voltage units (36, 48 volt), exercise extreme care during installation. These
voltages can be extremely dangerous in that they can create large arcs, which can burn or
cause other injuries.
INSTALLATION INSTRUCTIONS:
1. LOCATION: - A suitable location must be found for mounting the SC1. The unit should be
mounted on a vertical surface and be as close as possible to the batteries to avoid errors in
battery voltage reading. DO NOT block the ventilation holes on the top and bottom of the SC1.
On units with temperature compensation (Option A), the sensor wire is 10 feet long and
should reach the battery bank if possible. For installation details on temperature
compensation, refer to OPTIONS section.
2. PROTECTION REQUIREMENTS: - The unit should not be placed in direct sunlight or close to
any heat generating source to avoid extreme temperature increases. It must receive adequate
protection from rain, dust and insects. The SC1 is NOT designed to be mounted outdoors or in
high humidity environments unless protected by a suitable enclosure.
3. MOUNTING: - Secure the SC1 to the selected location using the four mounting holes on the
chassis and proper fasteners.
4. COMPLETE THE INSTALLATION OF THE PANELS, BATTERIES AND LOAD: - Follow the
manufacturer's instructions for mounting and wiring the solar panel, batteries and the load.
5. SELECT WIRE:
WIRE TYPE: - It is recommended that stranded wire rather than solid wire be used
whenever possible, because stranded wire does not fatigue and cause loose
connections over time as easily as solid wire does.
WIRE SIZE: - The SC1 terminal block accepts bare wire up to 10 AWG. (The 50 amp
model accepts up to 6 AWG). Wire should be sized of sufficient gauge to safely handle
the rated current of the system and to limit voltage drop. Consult wire sizing tables and
local alternative energy system suppliers for information on wire sizing.
6. REMOVE POWER FROM BATTERY / PANELS: - Disconnect power from the batteries and
panels prior to running the wires to the SC1 to prevent accidental damage or bodily harm.
7. SET CIRCUIT BREAKER TO “OFF”: - Make sure the load circuit breaker on the SC1 is
“OFF”.
8. RUN SYSTEM WIRING: - After disconnecting the power sources, refer to wiring diagram
(FIGURE 1) and run the system wiring to the location of the SC1. The wires should reach the
location of the SC1 with a little extra for strain relief loops.
9. NOTE WIRE POLARITY: - Insure that the polarity of the wires is correctly marked, using
colored wires or tags. Incorrect polarity should not damage the SC1, but incorrect operation
would result.
10. COMPLETE ARRAY AND BATTERY CONNECTIONS: - Connections to the SC1 terminal
block should be made with just the bare wire (not crimped spade or ring lugs unless the lugs
are crimped AND soldered)
11. COMPLETE LOAD CONNECTIONS: - Refer to wiring diagram (FIGURE 1). DC loads not
exceeding the rated SC1 load current (see specification section “Load Current, Continuous”)
can be connected to the load terminals of the SC1 and they will automatically be disconnected
in the event of a low-voltage condition. Higher current, or inductive loads such as pumps,
motors or inverters should be connected directly to the battery, using properly rated overcurrent protection devices (fuses or circuit breakers).
12. BATTERY VOLTAGE SENSE CONNECTIONS: - The factory has installed two jumpers onto
the terminal block. They connect the "BATTERY VOLTAGE SENSE" (positive and negative)
terminal to their respective "BATTERY" terminals. These jumpers should remain in place if
the SC1 is located within 5-10 feet of the batteries and if large enough wire is used to
minimize voltage drops to less than 2%.
If the SC1 is at a greater distance from the batteries and/or if the voltage drop in the
battery wires exceeds 2%, then the jumpers should be removed and replaced with another
circuit running directly to the battery terminals. This is a low current, voltage sensing circuit
that can be wired in 16 AWG wire. Proper over-current protection should be added on the
positive side. This connection will allow the SC1 to accurately measure battery voltage.
13. INSTALL FUSING AS NEEDED: - Add circuit protection where needed. A 30 amp fuse
(or 50 amp with Option P) should be installed on the Battery (+) run of the SC1. Fusing is also
advised for the battery voltage sense connection, if included. The load is already protected by
the built-in circuit breaker of the SC1.
14. ATTACH TEMPERATURE COMPENSATION CABLE (OPTION A): - If included. See
Temperature Compensation section
15. MAKE NEEDED ADJUSTMENTS TO VOLTAGE SET-POINT (OPTION T): - If included.
See Setting/Adjustments section
16. RECONNECT BATTERY AND ARRAY POWER - Reconnect both power sources, then
Step 8 Battery Voltage Sense(+)( # 1): To Battery (+) (Remove #1-#2 jumper)
position the load circuit breaker on.
POWER CONNECT SEQUENCE
It is recommended that the power is supplied to the system using this sequence.
Some of the circuits within the SC1 must be reset to their "start state" and this is
automatically accomplished if the power is supplied in this order. If the order is not
followed, a period of up to 24 hours may have to elapse before the electronics are
fully reset.
Step 1 Battery (-) (terminal # 7): To Battery (-)
Step 2 Battery (+)( # 2): To Battery (+)
Step 3 Solar Panel (-)( # 6): To Solar Panel Array (-)
Step 4 Solar Panel (+)( # 3): To Solar Panel Array (+)
Optional (see “COMPLETE LOAD CONNECTION” above)
Step 5 Load (-)( # 5): To Load (-)
Step 6 Load (+)( # 4): To Load (+)
If Needed (see “BATTERY VOLTAGE SENSE CONNECTIONS” above)
Step 7 Battery Voltage Sense(-) ( # 8): To Battery (-). (Remove #7-#8 jumper)
17. OPERATION: - Operation of the charge controller is now fully automatic. If the battery
voltage is below the Full Charge Termination set-point (see SPECIFICATIONS) and power is
available from the array and the Power Connect Sequence (above) was followed, the SC1
should start up in the full-charge mode. If the battery voltage is above the Load Disconnect
voltage, the loads connected to the LOAD terminals should go on.
During float charging (12 or 24 volt units) it is normal for the unit to feel warm. This is due to
power dissipation of the voltage regulated float circuit.
18. CHECK FOR VOLTAGE DROP (OPTIONAL): - Once the system is installed and operational,
a check on the battery connection is recommended. A poor battery connection will result in a
voltage loss that will cause the batteries to be under-charged and/or result in excessive heat
generated at the location of poor connection (wire connection or terminal block). A voltage
multi-meter is required and the SC1 must be in Full Charge mode with maximum expected
charge current.
First, note the voltage at the battery terminals. Select the positive and negative terminals that
are used for the SC1 connection. Then note the voltage at the SC1 terminals labeled “BATT
(+)” and “BATT (-)”. The difference in voltage should be no more than ¼ volt (for a 12 volt
system). If the voltage drop is more, suspect crimp connections that have not been soldered
or loose terminals. If no location of voltage drop is found, consider using larger wires for your
run or run a separate wire for the Battery Sense connection. See “BATTERY VOLTAGE
SENSE CONNECTION” (above).
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