Morningstar SunSaver SS-6 User manual

PHOTOVOLTAIC SYSTEM CONTROLLERS
O PERATOR ’ S M ANUAL
SUNSAVER MODELS
INCLUDED IN THIS MANUAL
• SS-6 / SS-6L 6A / 12V
•
SS-10 / SS-10L 10A / 12V
•
SS-10-24V / SS-10L-24V 10A / 24V
•
SS-20L 20A / 12V
•
SS-20L-24V 20A / 24V
1098 Washington Crossing Road
Washington Crossing, PA 18977 USA
Website: www.morningstarcorp.com

2
SPECIFICATION SUMMARY
SS-6 SS-10 SS-20 24 Volt
System Volts (V) 12 12 12 24
Maximum PV Volts (V) 25 25 25 44
Rated PV Input (A) 6.5 10 20 n/a
Rated Load (A) 6 10 20 n/a
Maximum array short (A) 8.1 12.5 25 n/a
circuit current
Setpoints:
Sealed PWM (V) 14.1 14.1 14.1 28.2
Flooded PWM (V) 14.4 14.4 14.4 28.8
LVD (V) 11.5 11.5 11.5 23.0
LVD Reconnect (V) 12.6 12.6 12.6 25.2
Ambient Temp Range (°C) –40 to 60 –40 to 60 –40 to 60 –40 to 60
Temp Compensation (mV/°C) –28 –28 –28 –56
0.50
(13)
1.32
(34)
4 MOUNTING HOLES ø0.20 (5.0)
2.18
(55)
1.00
(25)
6.00 (152)
5.50 (140)
DIMENSIONS INCHES (MM)

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CONTENTS
1.0 G
ENERAL I NFORMATION .............................................. 4
2.0 I MPORTANT S AFETY I NSTRUCTIONS .............................. 4
2.1 Installations in Hazardous
(Classified) Locations .............................................. 4
3.0 Q UICK S TART I NSTRUCTIONS ........................................ 5
4.0 LED I NDICATORS .............................................................. 6
5.0 I NSTALLATION I NSTRUCTIONS ............................................ 7
5.1 Ratings and Limits ............................................ 7
5.2 Polarity Protection ............................................ 8
5.3 Installation Procedure ...................................... 8
6.0 O PERATION ................................................................10
6.1 Operator Tasks ................................................10
6.2 Operation and Functions ................................11
6.3 Inspection and Maintenance ............................12
7.0 T ESTING AND T ROUBLESHOOTING ................................13
7.1 Testing with a Power Supply ............................13
7.2 Troubleshooting................................................13
8.0 S PECIFICATIONS ..........................................................16

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1.0 GENERAL INFORMATION
Thank you for selecting the SunSaver™ PV controller. The
SunSaver is a sophisticated controller using advanced tech-
nology and series switching PWM charging. The battery
charging process has been optimized for longer battery life
and improved system performance.
Many specifications of the SunSaver are unique. Although the
SunSaver is very simple to use, please take the time to read
this operator’s manual and become familiar with the controller.
This will help you to make full use of the many advantages the
SunSaver can provide to your PV system.
2.0 IMPORTANT SAFETY INSTRUCTIONS
•SAVE THESE INSTRUCTIONS—This manual contains impor-
tant instructions that should be followed during installation
and maintenance of the SunSaver 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 instructions provided with the battery.
• Do not exceed the voltage or current ratings of the con-
troller. 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 cop-
per wire with minimum 75˚C insulation rating and between
10 AWG (5.2 mm2) and 14 AWG (2.1 mm2) gage.
• The negative system conductor should be properly
grounded. Grounding should comply with local codes.
2.1 I NSTALLATIONS IN H AZARDOUS (C LASSIFIED ) L OCATIONS
The SunSaver family of charge controllers have been listed to
UL1604 and CSA 22.2 No. 213-M1987 for use in Class I, Division
2, Groups A, B, C and D hazardous locations. In order to comply
with the UL and CSA standards, the installation should follow the

5
requirements of the National Electrical Code Article 501-4(b)
and/or Canadian Electrical Code Article 18-156 when installing a
SunSaver in a Hazardous (Classified) Location.
WARNING:Do not disconnect while the circuit is alive
unless the area is known to be nonhazardous.
AVERTISSEMENT: Risque D’explosion—Avant De
Deconnecter L equipment; Couper Le
Courant Ou S’assurer Que L’emplacement
Est Designe Non Gereux.
3.0 QUICK START INSTRUCTIONS
This section provides a brief overview of how to get started
using the SunSaver controller. However, please review the
entire manual to ensure best performance and years of trouble-
free service.
1. Mount the SunSaver 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 SunSaver model being installed.
3. The 6 system connections to the SunSaver 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.
+–
BATTERYSOLAR LOAD
4
+–+–
3 2 1 6 5
{
PHOTOVOLTAIC CONTROLLER
12 Volts
6.5A Solar
6.0A Load
LOAD
DISCONNECT
CHARGING
Remove
Jumper
Wire for
Flooded
Battery
TEMP. SENSE
MORNINGSTAR
SEALED
OR
FLOODED
SELECT
3
Õ
1
UP
2
4
6
7
8
5
BATTERY

6
5. Connect the SOLAR (PV array) next. The green LED indicator
will light if sunlight is present.
6. Connect the LOAD last. If this model includes an LVD and
the red LED indicator lights, the battery capacity is low and
should be charged before completing the system installation.
(Refer to Section 5.3)
7. The controller is shipped with a 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 bat-
tery. If the jumper is connected again, the charging will return
to the setpoints for a sealed battery. (Refer to Section 5.3)
8. For most effective surge protection, it is recommended that
the battery negative conductor be properly grounded.
4.0 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 SunSaver 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 (during the daytime). This is to indi-
cate that the controller is working and that energy is available
from the PV array for charging.
R ED LED:
If your SunSaver model includes an automatic load disconnect
(LVD) feature, a red LED indicator is also provided. Whenever
the battery charge state falls below the LVD setpoint, the load
will be disconnected and the red LED will light. This indicates
that the controller has disconnected the load to protect the
battery from further discharge and possible damage.
After some period of recharging the battery such that it recov-
ers to approximately 40 to 50 percent of its rated capacity, the
load will automatically be reconnected and the red LED will
turn off.

7
5.0 INSTALLATION INSTRUCTIONS
5.1 R
ATINGS AND L IMITS
•The SunSaver is rated for 12 volt (or 24 volt) PV systems. Do
not connect to a PV array with open circuit voltage (Voc)
greater than 25 (or 44) volts.
• Maximum array short circuit current rating:
S UN S AVER -6 8.1 amps
S UN S AVER -10 12.5 amps
S UN S AVER -20 25.0 amps
• Because the SunSaver is a series controller, the PV current
rating is specified at the PV array’s peak power (Ipp). The
SunSaver 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.
• SunSaver models with an automatic low voltage load discon-
nect function (LVD) are rated for either 6, 10 or 20 amp loads
depending on the model.
• SunSaver models without an LVD capability are rated for a
maximum load of 10 amps. All loads connected to the SunSaver
LOAD terminals should not exceed 10 amps of current.
N OTE : It is not necessary to use the SunSaver load
terminals. Loads that exceed the load rating of the
SunSaver can be connected directly to the battery.
• 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 SunSaver is designed to operate continuously in 60°C
ambient temperatures. However, do not install the controller
near heat generating sources or in direct sun. This could
cause the temperature 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.

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5.2 P OLARITY P ROTECTION
The SunSaver is generally protected from reversed connec-
tions, 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.
5.3 I NSTALLATION P ROCEDURE
N OTES :
•The SunSaver 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 mm2). A flathead screwdriver is
required. (Some #10 spade connectors may not fit in this
terminal.)
• Tighten each terminal clamping screw to 20 inch-pounds of
torque.
• The SunSaver is designed to regulate power from a PV
array. Other generators can be connected directly to the
battery, however, with no effect on the SunSaver.
• Do not connect any system wires (Solar, Battery, Load) to
the SEALED OR FLOODED SELECT terminal.
•The installation should follow the requirements of the U.S.
National Electric Code, Section 690.
• The installation should follow the requirements of the
National Electrical Code Article 501-4(b) and/or Canadian
Electrical Code Article 18-156 when installing a SunSaver in
a Hazardous (Classified) Location.
Refer to the connection diagram on page 5 to illustrate each of
the following installation steps.
1. Inspect the controller for shipping damage. If possible,
mount the SunSaver 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 SunSaver can be mounted outdoors. Avoid mounting in
in direct rain such that water could collect under the cover. If
installed in an enclosure, some ventilation is recommended
to minimize operating temperatures.

9
N OTE : The SunSaver is very corrosion resistant. The case
is hard coat anodized, cover screws are stainless
steel, the circuit is encapsulated, and the termi-
nals are copper and nickel plated brass.
2. Confirm that the PV array and loads will not exceed the
current ratings of the SunSaver model being installed
(see specifications on page 2).
N OTE : Multiple SunSavers can be connected in parallel
to charge a single battery. Make sure each PV
sub-array does not exceed the solar rating of the
SunSaver, and be careful not to connect a load
that exceeds a single SunSaver’s load rating.
Separate loads can be connected to different
SunSavers.
3. CONNECTION ORDER The label has each system connec-
tion numbered from 1 to 6. This is the recommended order
of system connections. However, a different order will not
damage the controller.
4. BATTERY Connect the 12-volt (or 24-volt) system battery.
The green LED will not light. If a red LED (LOAD DISCON-
NECT) is provided with this model and it lights, the battery
charge state is low and should be recharged before
completing the installation.
N OTE : If the battery voltage is below 11.5 volts (or
23.0 volts), the load has been automatically
disconnected due to a very low battery charge
condition, and the battery must be recharged.
N OTE : If the battery voltage is between 11.5 and 12.0
(or 23 and 24) volts, the SunSaver will sometimes
power-up during initial installation in the LVD
(load disconnected) state. This will automatically
clear when the battery voltage rises above 12.6
(or 25.2) volts. The LVD can also be reset manual-
ly (only if the battery voltage is above 11.5 (or 23)
volts). First connect the SOLAR array (see step 5
below). Next disconnect and then reconnect the
BATTERY positive wire. The red LED will turn off
to indicate that the LVD has been reset.

10
5. SOLAR First, be certain the battery (+ and –) is connected
correctly. Then connect the PV 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.
C AUTION : Remember that the PV array will generate
power whenever in sunlight. Also, be careful
not to SHORT-CIRCUIT the PV array while
connected to the controller, since this will
DAMAGE the controller.
6. LOAD Turn the load off. Connect the load to the LOAD
terminals, and then turn the load on.
If the load causes the red LED to turn on (for models with
LVD) soon after the load was activated, the battery must be
recharged. (see Section 6.2)
7. SEALED OR FLOODED SELECT The SunSaver is shipped
with a jumper installed between the LOAD -negative terminal
(connection 5) and the SEALED OR FLOODED SELECT ter-
minal. With this jumper installed, the SunSaver is configured
for charging SEALED batteries.
If your PV system has a FLOODED battery, simply remove
the jumper to change the SunSaver to a flooded battery
charger. (see Section 6.2)
The SunSaver 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
negative conductor of the PV system should be properly
grounded. The SunSaver connects the PV-negative, Battery-
negative and Load- negative internally per UL recommenda-
tions. No switching is done in the negative current path.
6.0 OPERATION
6.1 O
PERATOR T ASKS
The SunSaver is a fully automatic PV system controller that
includes electronic functions to protect both the controller and

11
the PV system. Battery charging is managed by a constant volt-
age PWM algorithm that has been optimized for PV systems.
The only manual tasks performed by the operator are:
a. Installation (see Section 5.3 )
b. Battery type selection (see Section 5.3-7)
c. Maintenance (see Section 6.3)
6.2 O PERATION AND F UNCTIONS
The PV system operator should become familiar with the fol-
lowing operating functions and design of the SunSaver con-
troller. Refer to the Technical Specifications (Section 8.0) 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.
• Battery Charge Regulation
SunSaver uses an advanced series PWM charge control for
constant voltage battery charging. A true 0 to 100% PWM
duty cycle is very fast and stable for positive charge control
under all system conditions.
• Temperature Compensation
A sensor next to the green LED measures ambient temp-
erature conditions. The SunSaver corrects the constant
voltage setpoint –28 (–56 for 24V) 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 controller are in a similar
thermal environment.
•Sealed / Flooded Select
Flooded batteries require more vigorous charging to avoid
stratification, and sealed batteries require precise control to
avoid outgassing. The SunSaver constant voltage setpoints
are 14.4 (or 28.8) volts for flooded batteries, and 14.1 (or
28.2) volts for sealed batteries. See Section 5.3-7 for more
information.
•LED Indicators
See Section 4.0

12
•Low Voltage Disconnect (LVD)
The automatic load disconnect is an option. If the battery
falls below 11.5 (or 23.0) volts, the load is disconnected from
the battery to protect against harmful deep discharges. A
2-second delay prevents load disconnects from transients.
The load is automatically reconnected when the battery
voltage recovers to 12.6 (or 25.2) volts.
• Battery Disconnect
If the battery is disconnected during the daytime, the PV
array will continue to provide power to the controller. The
SunSaver will immediately go into PWM and provide power
at a constant voltage to the load. This may continue as long
as power is available from the PV array.
•Parallel Controllers
The SunSaver controllers work very well in parallel configura-
tions. 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 SunSaver’s rating
for PV and load current is not exceeded. (see Section 5.3-2)
• Auxiliary Generators
Engine generators and other sources of power may be con-
nected directly to the battery for charging. It is not necessary
to disconnect the SunSaver from the battery. However, do
not use the SunSaver to regulate these other generators.
•Reverse Current
The SunSaver prevents the battery from discharging through
the PV array at night. There is no need to install a blocking
diode for this purpose.
• Noise
The SunSaver circuit minimizes switching noise and filters
all noise output to extremely low levels when the system
is properly grounded. If noise is present in a telecom load, it
is most likely a grounding problem in the system.
6.3 I NSPECTION AND M AINTENANCE
The following inspections and maintenance tasks are
recommended at least once per year for best controller perfor-
mance.
1. Confirm that the correct battery type has been selected
(sealed or flooded with the jumper).

13
2. Confirm that the current levels of the PV array and load do
not exceed the SunSaver 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. Check that the controller is securely mounted in a clean
environment. Inspect for dirt, insects, and corrosion.
5. Check that air flow around the controller is not blocked.
6. Protect from direct sun and rain. Confirm that water is not
collecting under the cover.
7. Check that the controller functions and LED indicators are
correct for the system conditions at that time.
7.0 TESTING AND TROUBLESHOOTING
7.1 T
ESTING WITH A P OWER S UPPLY
Normal SunSaver operation can be tested with a power supply
used in place of either the PV array input or the
battery. To be certain the SunSaver will not be damaged,
observe the following cautions:
•Current limit the power supply to no more than one half the
SunSaver rating.
•Set the power supply 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 SunSaver
controllers with a power supply contact the
Morningstar Web Site for test procedures
7.2 T ROUBLESHOOTING
The SunSaver 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 SunSaver controller is simple. Some basic
troubleshooting procedures are listed on the next page.

14
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 SunSaver.
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 con-
troller 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
SunSaver terminals. If the voltage at the terminals is the
same (within a few tenths of volts) the PV array is charging
the battery. If PV voltage is close to the open circuit voltage
of the panels and the battery 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 volt-
age is higher than specifications. Consider the temperature
compensation of the controller’s PWM setpoint. For example,

15
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 terminal and leave the PV array disconnected. The
Green charging light should not be lit. Measure the voltage
at the SOLAR terminals (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. 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 SunSaver.
b. Check connections to the load, and other controller and bat-
tery connections. Make sure voltage drops in the system
wires are not too high.
c. Check for proper LED indications on the SunSaver. If the red
LOAD DISCONNECT LED is on, the load has been discon-
nected 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.
d. Measure the voltage at the controller BATTERY terminals. If
this voltage is above the LVD, the load should have power.
Then measure the voltage at the controller LOAD terminals,
and if there is no voltage present, the controller may be
defective.
N OTE : For more detailed testing instructions contact
the Morningstar web site.

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101E-R4-2/00
8.0 TECHNICAL SPECIFICATIONS
RELIABILITY
5-year failure rates at a 95% confidence level
• SunSaver-6 ........................................ < 0.1%
• SunSaver-10 ...................................... <0.2%
PERFORMANCE / ELECTRICAL
• Accuracy:
Sealed............................................ +/–35 mV
Flooded ........................................ +/–60 mV
LVD ................................................ +/–100/160
mV
• Maximum array voltage .................... 25 V/44 V
• Minimum voltage to operate............ 6 V
• Ground .............................................. negative
• Parallel capability .............................. yes
• Self-consumption: ............................ 8 to 10 mA
• Voltage drops (typical):
PV/Battery...................................... 0.4 volts
Battery/Load.................................. 0.3 volts
• Operating life.................................... 15 years
• Transient surge suppressors:
Pulse power rating ........................ 1500 watts
Response ...................................... < 5 nanosec
• 25% current overload capability ...... 5 minutes
• Reverse current leakage.................... < 10 µA
ENVIRONMENTAL
• Operating temperature .................... –40 to +85°C
• Max ambient temperature................ +60°C
• Storage temperature ........................ –55 to +100°C
• Humidity............................................ 100%
MECHANICAL
• Dimensions: (inches) .... 6.0 x 2.2 x 1.3 (W•H•D)
(mm) ........ 152 x 56 x 33 (W•H•D)
• Weight (oz)............ 8
(kg) .......... 0.23
• Wire terminals:
Wires per terminal...... 1 or 2 wires
Max size per wire........ #10 AWG
5.2 mm2
Screw material............ Nickel plated brass
Terminal material........ Tin/Copper plated brass
• Encapsulation ................ Epoxy
• Case................................ 6063-T5 Aluminum
• Finish .............................. Electrolytic anodize
• Mounting orientation .... Any
CONTROL SETPOINTS
Sealed Flooded
• Low volt load disconnect ........ 11.5 11.5
• LVD reconnect .......................... 12.6 12.6
• Constant-voltage regulation .... 14.1 14.4
(24 V setpoints are twice 12 V values)
CONTROL PARAMETERS
• Charge algorithm .......... constant-voltage
series configuration
• PWM duty cycle.............. 0% to 100%
• Temp comp coefficient... –28 mV/°C (25°C ref) 12V
–56 mV/°C (25°C ref) 24V
• LVD delay ...................... 2 seconds
Specifications subject to change without notice.
E112204
For Use In Cl I, Div 2, GpABCD
Hazardous Locations
UL1604 CSA22.2 No. 213-M1987