Morningstar Sunlight SL-10 User manual

SOLAR LIGHTING CONTROLLER
O PERATOR ’ S M ANUAL
SUNLIGHT MODELS
INCLUDED IN THIS MANUAL
• SL-10 10A / 12V
•
SL-10-24V 10A / 24V
•
SL-20 20A / 12V
•
SL-20-24V 20A / 24V
1098 Washington Crossing Road
Washington Crossing, PA 18977 USA
Website: ww.morningstar.com

inches (mm)
4 MOUNTING HOLES ø0.20 (5.0)
1.32
(34)
2.18
(55)
1.00
(25)
6.60 (168)
6.10 (155)
4 3 2 1 6 5
SEALED
OR
FLOODED
SELECT
SOLAR LIGHTING CONTROLLER
+–+–+–
12 Volts
10A Solar
10A Load
LOW VOLTAGE
DISCONNECT
TEMP. SENSE
MORNINGSTAR
TEST
LIGHTING CONTROL
CHARGING
2
OFF
4
6
8
10
3/1
4/2
6/2
D/D
System Voltage 12 12 24 V
Maximum Voltage 30 30 50 V
Rated Solar Input 10 20 n/a A
PV Short Circuit Rating 12.5 25 n/a A
Rated Load 10 20 n/a A
25% Current Overload 5 5 n/a minutes
Regulation Voltage:
Sealed PWM 14.1 14.1 28.2 V
Flooded PWM 14.4 14.4 28.8 V
LVD 11.7 11.7 23.4 V
LVD Reconnect 12.8 12.8 25.6 V
Temp Compensation –27 –27 –54 mV/°C
Self-consumption 8 8 9 mA
Ambient Temp Range –40 to 60 –40 to 60 –40 to 60 °C
SPECIFICATION SUMMARY
SL-10 SL-20 24 Volt

1
CONTENTS
1.0 G ENERAL I NFORMATION ................................................ 1
2.0 I MPORTANT S AFETY I NSTRUCTIONS .................................. 2
3.0 Q UICK S TART I NSTRUCTIONS .......................................... 2
4.0 L IGHTING C ONTROL O PTIONS ........................................ 3
5.0 LED I NDICATORS ................................................................ 4
6.0 I NSTALLATION I NSTRUCTIONS .............................................. 4
6.1 Ratings and Limits ................................................ 4
6.2 Polarity Protection ................................................ 5
6.3 Brownout Protection ............................................ 5
6.4 Installation Procedure .......................................... 5
7.0 O PERATION .................................................................. 8
7.1 Select Lighting Control Option ............................ 8
7.2 Test Button............................................................ 8
7.3 Operator Tasks...................................................... 9
7.4 Operation and Functions...................................... 9
7.5 Inspection and Maintenance ................................12
8.0 T ESTING AND T ROUBLESHOOTING ..................................12
8.1 Testing with a Power Supply ................................12
8.2 Troubleshooting....................................................13
1.0 GENERAL INFORMATION
Thank you for selecting the SunLight™ solar lighting controller.
The SunLight is an advanced design using a microcontroller for
digital accuracy and fully automatic operation. The PWM bat-
tery charging has been optimized for longer battery life.
Many specifications of the SunLight are unique. Although the
SunLight is very simple to use, please take the time to read this
operator’s manual and become familiar with the controller. This

2
will help you to make full use of the many advantages the
SunLight can provide to your solar lighting system.
2.0 IMPORTANT SAFETY INSTRUCTIONS
•SAVE THESE INSTRUCTIONS—This manual contains important
instructions that should be followed during installation and main-
tenance of the SunLight controller.
• WARNING—Be very careful when working with batteries. Lead
acid batteries can generate explosive gases, and short circuits
can draw thousands of amps from the battery. Read all instruc-
tions provided with the battery.
• Do not exceed the voltage or current ratings of the controller.
Use only with a 12 volt or 24 volt battery.
•
DO NOT short circuit the PV array or load while connected to
the controller. This will DAMAGE the controller.
• The controller should be protected from direct sunlight. Ensure
adequate space for air flow around the controller.
• Pressure terminal connectors are not required. Use only copper
wire with minimum 75˚C insulation rating and between 10 AWG
(5.2 mm
2
) and 14 AWG (2.1 mm
2
) gage.
• The negative system conductor should be properly grounded.
Grounding should comply with local codes.
3.0 QUICK START INSTRUCTIONS
This section provides a brief overview of how to get started using
the SunLight controller. However, please review the entire manual
to ensure best performance and years of trouble-free service.
1. Mount the SunLight to a vertical surface. Allow space above and
below the controller for air flow.
2. Make sure the PV and load currents will not exceed the ratings
of the SunLight model being installed.
3. The 6 system connections to the SunLight terminals
are numbered on the label. It is recommended that the
connections be made in order from 1 to 6.
4. Connect the
BATTERY first. Use care that bare wires do not
touch the metal case of the controller.
5. Connect the
SOLAR (PV array) next. The green LED indicator will
light if sunlight is present.

3
6. Connect the LIGHT last. If the red LED indicator lights, the bat-
tery capacity is low and should be charged before completing
the system installation (Refer to Section 6.4).
7. The controller is shipped with a terminal jumper installed. This
sets the controller for charging
SEALED batteries.
If a
FLOODED battery is being used, simply remove the jumper
to optimize the battery charging for a flooded battery. If the
jumper is connected again, the charging will return to the set-
points for a sealed battery (Refer to Section 6.4.)
8. For most effective surge protection, it is recommended that the
negative system conductor be properly grounded.
9. Turn the rotary
LIGHTING CONTROL switch to the lighting
option desired (Refer to Section 7.1).
10. Press the
TEST button and count the number of Red LED flashes
to verify the correct lighting control setting (Refer to Section 7.2).
4.0 LIGHTING CONTROL OPTIONS
SOLAR LIGHTING CONTROLLER
+–
BATTERYSOLAR
4
+–+–
3 2 1 6 5
12 Volts
10A Solar
10A Light
LOW VOLTAGE
DISCONNECT
TEMP. SENSE
MORNINGSTAR
MADE IN USA
SEALED
OR
FLOODED
SELECT
LIGHT
TEST
LIGHTING CONTROL
CHARGING
2
OFF
4
6
8
10
3/1
4/2
6/2
D/D
12 V
4
6
7
8
5
3
Õ
1
UP
2
9
10
• OFF
• 2 HOURS ON
• 4 HOURS ON
• 6 HOURS ON
• 8 HOURS ON
• 10 HOURS ON
• 3 / OFF / 1
• 4 / OFF / 2
• 6 / OFF / 2
• DUSK-to-DAWN
SUNSET NIGHT SUNRISE

5.0 LED INDICATORS
G
REEN LED:
The green LED indicator will light whenever sunlight is avail-
able for battery charging. The green LED will turn off at night.
Because the SunLight uses a PWM constant voltage charging
process, there is usually some amount of energy going into the
battery at all times. Although the charging current falls to very
low levels when the battery reaches full charge, the green LED
will continue to stay ON all day. This is to indicate that the
controller is working and that energy is available from the PV
array for charging.
R ED LED:
The red LED is an indicator for 3 different functions:
• Automatic low voltage load disconnect (LVD)
If the battery charge state falls below the LVD setpoint, the light
will be disconnected and the red LED will light. This indicates the
controller has disconnected the load to protect the battery from
further discharge and possible damage. The red LED will turn off
when the battery recovers to about 50% of its rated capacity and
the load is automatically reconnected.
• Initial controller start-up
When the SunLight is properly connected to the battery, the red
LED will flash 3 times.
• Confirm lighting control selection
When the TEST button is pressed, the red LED will confirm the
lighting control option selected by the rotary switch (Refer to
Section 7.2).
6.0 INSTALLATION INSTRUCTIONS
6.1 R
ATINGS AND L IMITS
•The SunLight is rated for 12 volt (or 24 volt) PV systems. Do not
connect to a PV array with open circuit voltage (Voc) greater than
30 volts (or 50 volts).
• Maximum array short circuit current rating is 12.5 amps and
25 amps.
4

5
•Because the SunLight is a series controller, the PV current rating
is specified at the PV array’s peak power (Ipp). The SunLight does
NOT short the PV array for regulation, and it is not necessary to
derate the controller for short-circuit current (Isc) as is commonly
done with shunt controllers.
• The rated PV input current and the rated load current can both
be exceeded by 25% for up to 5 minutes. This 25% overload will
reduce the safety margins for surges and will cause heating that
can shorten the life of the controller.
For the reasons noted above, these higher overload ratings
should
NOT be used for routine operation. They are only to note
overload capability for system design purposes.
• The SunLight is designed to operate continuously in 60°C ambi-
ent temperatures. However, do not install the controller near heat
generating sources or in direct sun. This could cause the temper-
ature rating to be exceeded and damage the controller.
• The date of manufacture can be found on the serial number
(bottom of case). The first 4 digits are the year and week.
6.2 P OLARITY P ROTECTION
The SunLight is generally protected from reversed connections,
but the system operator and other equipment will be at risk
when polarities (+ and –) are reversed. Carefully check before
making each connection to be certain the polarity is correct.
6.3 B ROWNOUT P ROTECTION
If battery voltage sags below 8 volts for any reason (such as
pressing TEST in LVD with a weak battery), the microcontroller
may reset. This is to prevent a low voltage condition from
causing the microcontroller to lock-up at an unattended site.
Note that a brownout reset will begin a new start-up sequence
for measuring night length (Refer to Section 7.4).
6.4 I NSTALLATION P ROCEDURE
N OTES :
• The SunLight prevents reverse current leakage at night, so a
blocking diode is not required in the system.
• The connector terminals will accept a maximum wire size of
AWG #10 (up to 5.2 mm
2
). A flathead screwdriver is required.
(Some #10 spade connectors may not fit in this terminal.)

6
• Tighten each terminal clamping screw to 20 inch-pounds of
torque.
• The SunLight is designed to regulate power from a PV array.
Other generators can be connected directly to the battery,
however, with no effect on the SunLight.
• Do not connect any system wires (Solar, Battery, Light) to the
SEALED OR FLOODED SELECT terminal.
Refer to the connection diagram on page 3 to illustrate each of the
following installation steps.
1. Inspect the controller for shipping damage. If possible, mount
the SunLight to a vertical surface.
Allow a minimum of 5 cm (2 inches) space above and below the
controller for air flow. Protect the controller from direct sunlight
or other heat sources.
The SunLight can be mounted outdoors. Avoid mounting in
direct rain such that water could collect under the cover. If
installed in an enclosure, some ventilation is recommended to
minimize operating temperatures.
N OTE : The SunLight is very corrosion resistant. The case is
hard coat anodized, cover screws are stainless steel,
the circuit is encapsulated, and the terminals are
copper and nickel plated brass.
2. Confirm that the Solar array and loads will not exceed the
current ratings of the Sunlight controller being installed.
N OTE : A SunSaver can be connected in parallel with a
SunLight for additional amps of solar charging. Make
sure each controller’s input rating is not exceeded.
The lighting load can only be connected to the
SunLight and cannot exceed the load rating.
3. CONNECTION ORDER The label has each system connection
numbered from 1 to 6. This is the recommended order of system
connections. The
BATTERY must be connected before the
SOLAR to properly start the microcontroller.
4.
BATTERY Connect the 12-volt (or 24V) system battery. The
green LED will not light. If the red LED (LOAD DISCONNECT)
lights and stays lit, the battery charge state is low and should be
recharged before completing the installation.

7
N OTE : If the battery voltage is below 11.7 (or 23.4) volts,
the load has been automatically disconnected due to
a very low battery charge condition, and the battery
must be recharged.
N OTE : A battery below 10 volts may not start the microcon-
troller properly. Make sure the battery is charged
before installing the system.
5. SOLAR First, be certain the battery (+ and –) is connected
correctly. Then connect the solar array to the SOLAR terminals.
(Be
CERTAIN that the PV + and – wires are connected correctly).
The green LED will light if the array is connected during the
daytime and the array is wired correctly.
N OTE : If the SOLAR is disconnected during installation,
the controller will see this as the first night and the
length of night will be too short. This will only affect
ON/OFF/ON settings, and will automatically be cor-
rected over 4 days. If the PV array is disconnected, it
is best to disconnect the battery and restart the
microcontroller before leaving the site.
C AUTION : Remember that the Solar array will generate power
whenever in sunlight. Also, be careful not to short-
circuit the PV array while connected to the con-
troller, since this will damage the controller.
6. LIGHT Connect the light to the LIGHT terminals. Turn the light
on with the TEST button (Refer to Section 7.2).
If the load causes the red LED to turn on soon after the light was
activated, the battery must be recharged.
7.
SEALED OR FLOODED SELECT The SunLight is shipped with
a jumper installed between the LIGHT -negative terminal (connec-
tion 5) and the
SEALED OR FLOODED SELECT terminal. With
this jumper installed, the SunLight is configured for charging
SEALED batteries.
If your PV system has a
FLOODED battery, simply remove the
jumper to change the SunLight to a flooded battery charger.
The SunLight can be changed between SEALED and FLOODED
as many times as you wish by using the jumper. Save the jumper
for future use in case your battery type is changed. If the jumper
is lost, a wire can also be used.

8. For safety and the most effective lightning protection, the nega-
tive conductor of the battery should be properly grounded. The
SunLight connects the PV-negative, Battery-negative and Load-
negative internally per UL recommendations. No switching is
done in the negative current path.
7.0 OPERATION
7.1 S
ELECT L IGHTING C ONTROL O PTION
After completing the system connections, select the desired
LIGHTING CONTROL option. Refer to Section 4.0 for a sum-
mary of the SunLight’s ten standard options for lighting control.
A brief description follows below:
OFF Lights remain turned off
2,4,6,8,10 Hours light is turned on after sundown
3/1, 4/2, 6/2
Light is turned on after sundown, turned off
during the night, and turned on again one hour
(3/1) or two hours (4/2, 6/2) before sunrise
D/D Dusk-to-Dawn, light is on all night
To select a lighting option, turn the rotary digital switch to the
desired position. An arrow in the rotary switch will point to the
selected position. This is a digital switch, so it will click into
each of the ten positions.
To confirm correct selection of the desired control option, press
the TEST button located below the rotary switch (see Section
7.2 below).
7.2 T EST B UTTON
Press the TEST button until a distinct click is heard and felt.
This button performs two functions:
a. Confirm rotary switch selection
To verify that the rotary digital switch is set at the desired position,
press the TEST button. The red LED will flash once per second.
Count these LED flashes to confirm the correct switch setting.
Each of the 10 LIGHTING CONTROL positions has a unique
number of flashes. These are as follows:
8

9
Switch # of Switch # of
Setting Flashes Setting Flashes
OFF 0 10 5
2 1 3/1 6
4 2 4/2 7
6 3 6/2 8
8 4 D/D 9
N OTE : Rotate the rotary switch one full cycle if there is an
incorrect or no LED flash (except for OFF setting).
b. Turn system lights on
Pressing the TEST button will turn the system lights on to verify cor-
rect installation or for troubleshooting a system problem. The lights
will be turned on anytime (day or night) for 5 minute intervals.
The lights can be turned on repeatedly with the TEST button
except when the system is in LVD (load disconnect/red LED on).
In LVD the TEST button will only work 3 times to avoid damaging
the battery.
If pressing the TEST button causes a load disconnect (LVD), the
lights will turn off. Wait 5 minutes and press TEST again to turn
the lights on in LVD.
7.3 O PERATOR T ASKS
The SunLight is a fully automatic solar lighting controller that
includes electronic functions to protect both the controller and
the PV system. The controller is designed to operate for long
intervals at remote, unattended sites.
The only manual tasks performed by the operator are:
a. Installation (see Section 6.4)
b. Select lighting control option (see Section 7.1)
c. Maintenance (see Section 7.5)
7.4 O PERATION AND F UNCTIONS
The PV system operator should become familiar with the
following operating functions and design of the SunLight
controller. Refer to the Specification Summary for actual
setpoints and other parameter values.
• 100% Solid State
All power switching is done with FETs. No mechanical relays are
used in the controller.

10
• Battery Charge Regulation
SunLight uses an advanced series PWM charge control for con-
stant voltage battery charging. A true 0 to 100% PWM duty cycle
is very fast and stable for positive charge control under all system
conditions.
• Day-Night Transition
The SunLight uses the solar array to detect day and night. The
transition to night requires a solar insolation level less than 2
percent. The transition back to day requires a high solar array
open-circuit voltage. Both state changes require 10 minutes of
continuous transition values before making the change. These
constraints avoid false transitions due to lightning or dark storm
clouds.
•Measure Night Length
The LIGHTING CONTROL options that turn the lights on again
before sunrise require that the SunLight measure the length of
the night. Therefore, the controller cannot turn the lights on
before sunrise the first night after installation (or after reconnect-
ing the battery). If the solar array is disconnected during service,
the controller will then measure a faulty night length. Either reset
the controller by reconnecting the battery, or this short “night”
will be automatically corrected by the controller after 4 days of
service.
N OTE : The SunLight uses the open circuit voltage of the
PV panel to determine the correct time for dawn
and dusk. If the PV panel is covered with debris
(e.g. snow, leaves, dirt), the PV panel voltage may
be too low which can cause load timing errors.
If the load is operating erratically, make sure the PV
panels are clean, there are no obstructions shading
the array, and the PV panels are oriented to the sun
correctly. The SunLight will automatically correct load
timing errors within 4 days of clearing the array.
• Temperature Compensation
A sensor next to the green LED measures ambient temperature
conditions. The SunLight corrects the constant voltage setpoint
–27 (or –54) mV per °C with a 25°C reference. This correction
matches the battery charging to the changing electrochemical
properties of the battery, and works best if the battery and con-
troller are in a similar thermal environment.

11
•Sealed / Flooded Select
Flooded batteries require more vigorous charging to avoid strati-
fication, and sealed batteries require precise control to avoid out-
gassing. The SunLight constant voltage setpoints are 14.4 volts
for flooded batteries, and 14.1 volts for 12 volt sealed batteries.
See Section 6.4-7 for more information.
• LED Indicators
See Section 5.0
• Low Voltage Disconnect (LVD)
If the battery falls below 11.7 (or 23.4) volts, the load is discon-
nected from the battery to protect against harmful deep dis-
charges. A one minute delay prevents load disconnects from
transients. The load is automatically reconnected when the bat-
tery voltage recovers to 12.8 (or 25.6) volts.
• Battery Disconnect
If the battery is disconnected during the daytime, the PV array
will continue to provide power to the controller. The SunLight will
immediately go into PWM and provide power at a constant volt-
age to the load. This will continue as long as sufficient power is
available from the PV array.
• Parallel Controllers
Morningstar controllers work very well in parallel configurations.
No blocking diodes are required. The only constraint is that each
controller must have an independent and separate PV subarray
and load. Make sure that each controller’s rating for PV and load
current is not exceeded.
• Auxiliary Generators
Engine generators and other sources of power may be connect-
ed directly to the battery for charging. It is not necessary to dis-
connect the SunLight from the battery. However, do not use the
SunLight to regulate these other generators.
• Reverse Current
The SunLight prevents the battery from discharging through the
PV array at night. There is no need to install a blocking diode for
this purpose.

12
7.5 I NSPECTION AND M AINTENANCE
The following inspections and maintenance tasks are recom-
mended at least once per year for best controller performance.
1. Confirm that the correct battery type has been selected (sealed
or flooded with the jumper).
2. Confirm that the current levels of the Solar array and load do not
exceed the SunLight ratings.
3. Tighten all the terminals. Inspect for loose, broken, or burnt wire
connections. Be certain no loose strands of wire are touching
other terminals.
4. Press the TEST button to verify the lights are working.
5. Check that the controller is securely mounted in a clean
environment. Inspect for dirt, insects, and corrosion.
6. Check that air flow around the controller is not blocked.
7. Protect from direct sun and rain. Confirm that water is not
collecting under the cover.
8. Check that the controller functions and LED indicators are correct
for the system conditions at that time.
9. Make sure the PV array is clean and clear of debris and snow.
Confirm the array is oriented correctly for the installation
location.
8.0 TESTING AND TROUBLESHOOTING
8.1 T
ESTING WITH A P OWER S UPPLY
Normal SunLight operation can be tested with a power
supply used in place of either the PV array input or the
battery. To be certain the SunLight will not be damaged,
observe the following cautions:
•Current limit the power supply to no more than one half the
SunLight rating.
•Set the power supply voltage to 15 volts DC or less for 12V
systems, and 30 volts DC or less for 24V systems.
• Connect only one power supply to the controller.
N OTE : For more information on testing SunLight controllers
with a power supply, contact the Morningstar
Website for test procedures.

13
8.2 T ROUBLESHOOTING
The SunLight is very rugged and designed for the most
extreme operating conditions. Most PV system problems will
be caused by connections, voltage drops, and loads.
Troubleshooting the SunLight controller is simple. Some basic
troubleshooting procedures are listed below.
C AUTIONS : 1. Troubleshooting should be done by qualified
personnel only.
2. Remember that a battery can cause serious
damage if shorted.
3. There are no user serviceable parts, fuses or
circuit breakers inside the SunLight.
4. Observe all normal precautions when working
with energized circuitry.
1. B ATTERY I S N OT C HARGING
a. Check the green LED indicator. The green CHARGING LED
should be on if it is daytime.
b. Check that the proper battery type (sealed or flooded) has been
selected.
c. Check that all wire connections in the system are correct and
tight. Check the polarity (+ and –) of the connections.
d. Measure the PV array open-circuit voltage and confirm it is within
normal limits. If the voltage is low or zero, check the connections
at the PV array itself. Disconnect the PV from the controller when
working on the PV array.
e. Check that the load is not drawing more energy than the PV
array can provide.
f. Check if there are excessive voltage drops between the controller
and the battery. This will cause undercharging of the battery.
g. Check the condition of the battery. Determine if the battery
voltage declines at night with no load. If unable to maintain its
voltage, the battery may be failing.
h.
Measure the PV voltage and the battery voltage at the SunLight
terminals. If the voltage at the terminals is the same (within a few
tenths of volts) the PV array is charging the battery. If the PV volt-
age is close to the open circuit voltage of the panels and the bat-
tery voltage is low, the controller is not charging the batteries and
may be damaged.

2. B ATTERY V OLTAGE I S T OO H IGH
a. First check the operating conditions to confirm that the voltage is
higher than specifications. Consider the temperature compensa-
tion of the controller’s PWM setpoint. For example, at 0°C the
controller will regulate at about 15.1 volts (for 12 volt flooded
batteries).
b. Check that the proper battery type (sealed or flooded) has been
selected.
c. Check that all wire connections in the system are correct and tight.
d. Disconnect the PV array and momentarily disconnect the lead
from the
BATTERY positive terminal. Reconnect the battery ter-
minal and leave the PV array disconnected. The Green charging
light should not be lit. Measure the voltage at the
SOLAR termi-
nals (with the array still disconnected). If the Green charging light
is on or battery voltage is measured at the
SOLAR terminals, the
controller may be damaged.
3. L OAD N OT O PERATING P ROPERLY
a. Press the TEST button to turn the lights on. This will assist in
troubleshooting the problem.
b. Check that the load is turned on. Check that no system fuses are
defective. Check that no system circuit breakers are tripped.
Remember that there are no fuses or circuit breakers inside the
SunLight.
c. Check connections to the load, and other controller and battery
connections. Make sure voltage drops in the system wires are not
too high.
d. Check for proper LED indications on the SunLight. If the red
LOAD DISCONNECT LED is on, the load has been disconnected
due to low battery voltage. This is generally a normal state when
the load exceeds the PV array output due to weather and other
sunlight conditions.
e. Check the PV array voltage under direct sun, with the array leads
disconnected. The voltage should be close to the expected open
circuit voltage for the panel type used.
f. Visually inspect the PV array and verify that the array is clear of
debris (e.g. leaves, snow, dirt) and that it is oriented correctly for
the installation location (See NOTE pg. 10).
g. Measure the voltage at the controller
BATTERY terminals. If this
voltage is above the LVD, the load should have power. Press the
test button and then measure the voltage at the controller
LOAD
terminals, and if there is no voltage present, the controller may
be defective.
103E-R2-2/99
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