AMERESCO TWIG-MC Solar Kit Installation Guide
- June 3, 2024
- AMERESCO
Table of Contents
AMERESCO TWIG-MC Solar Kit
INTRODUCTION
Thank you for purchasing an Ameresco Solar, Inc. solar electric power system. Ameresco Solar is a world leader in the design and marketing of solar electric power systems, with over three decades of experience and sales offices throughout the United States.
Important: Special Considerations, Before Beginning the Installation
To ensure proper operation of the power system, it must be installed per the
instructions in Section 3.
The solar electric system is designed to provide operating power to a specified load. Using loads other than those for which the system was designed for will result in poor system performance and possible damage to the batteries. Special care must be taken when selecting the solar module mounting location to prevent possible shadowing effects from cut hillsides, trees or utility poles. Any shading of the modules, during any period of the day, will result in a reduction in the output of the solar array and reduced system performance and must be avoided.
Additionally, the solar modules must be properly oriented for the specific geographic region to maximize the solar radiation available at the site. This includes the tilt angle and alignment to True South. While performing the installation of your Ameresco Solar system, consideration of the above factors will result in the system performing reliably to its’ original specifications.
Definition of Warning Statements
- DANGER: Failure to heed this warning may result in serious injury.
- CAUTION: Failure to heed this warning may result in damage to the load or system equipment.
- NOTE: Information or instructions that will assist in the proper installation and operation of the system.
Technical Support
We strive to provide quality service and support. Please feel free to contact
us at any time should a question arise as to the proper installation and
operation of the system. A proper installation will help to ensure reliable
system operation.
Ameresco Solar
120 E. Corporate Place, Suite 8
Chandler, AZ 85225
PH = 480-760-2500
FX = 855-255-5364
[email protected].
THEORY OF OPERATION
System Overview
There are three major components in this photovoltaic system: the solar module, batteries, and the system charge controller. Throughout the year, all the power required by the load is provided by the solar array.
The PV array will supply current to charge the battery bank. The controller will monitor the battery voltage and limit the charging current to the battery as required. The controller will bulk charge the battery to approximately 14.1 VDC, then taper the current to maintain a float voltage around 13.7 VDC. The controller also contains a temperature probe and adjusts the charge voltage at a rate of -0.030 VDC/°C from 25°C. (Refer to the controller manual provided in the kit or document package for additional details on charge regulation.)
The controller features a Low Voltage Disconnect (LVD) function. This will disconnect the load if battery voltage falls to approximately 11.5 VDC, during abnormal situations such as continuous days of cloudy weather. This will prevent the battery from being over-discharged to a level that could shorten its life. When the battery has been charged to a voltage of 12.5-12.8 VDC, the controller will reconnect the battery to the load.
Component Descriptions
Solar Modules
12V nominal 36 cell photovoltaic modules are used in the solar power system.
The modules have an open circuit voltage ranging from 20-24 VDC depending on
temperature and sunlight exposure. Typical peak power voltages are around
17-18VDC.
Batteries
Deka Solar gel type batteries are used in this system. The Valve Regulated
Lead Acid (VRLA) battery is specifically designed for deep cycle photovoltaic
systems. Refer to the System Wiring Diagram in the appendix for battery
capacity details.
Controller
A MorningStar charge controller is used in this system. The controller uses
PWM control of battery charging and features temperature compensation with an
internal temperature probe. Refer to the separate Morningstar manual for
additional information on the controller’s ratings and operation.
SYSTEM INSTALLATION
Perform the installation of the system in the order of and as described in the following subsections.
Overview
The SK System enclosure is pre-assembled and tested before shipping. All that is required is to mount the modules and enclosure on a pole (provided by others), install the batteries, and make the final wire terminations.
Recommended Installation Tools
- Compass (magnetic or GPS) Phillips & Flat Head Screwdrivers Socket Set Electrical Tape
- Digital Multimeter (DMM) Wire Cutters & Strippers Combination Wrench Set Cable Ties (for wire dressing)
Site Location
- Shading of the photovoltaic modules will significantly reduce their energy output and consequently proper battery charging! Be sure to select an array mounting location that will not be shaded by towers, poles, buildings, vegetation (e.g. trees), or hillside cuts through the day.
- In order for the solar array to receive the maximum energy from the sun, the array must face True South. It is recommended to use a GPS compass to find True South. Use of a magnetic compass will require adjustment to account for magnetic declination for your location, which may be over 15 degrees off from True South in eastern or western USA.
Mechanical Assembly
WARNING: Electrical Shocks and Burns Hazard
Photovoltaic (PV) modules generate electricity when exposed to light, even
when they are not connected in a circuit. Shocks and burns can result from
contact with module output wiring. These hazards are increased when multiple
modules are interconnected to increase array output current or voltage. Cover
module front surfaces completely with an opaque cloth or other opaque material
before performing any operation involving module or system electrical
connections. Use appropriate safety equipment (insulated tools, insulating
gloves, etc.) and procedures.
CAUTION: Module Breakage
The module glass is tempered and will shatter if exposed to impact. Avoid
rough handling and lay the modules on a flat, protected surface during
assembly. This will also prevent power output at the electrical terminals.
Avoid shorting the terminals whenever sunlight is present on the module front
surface.
Mounting Pole Installation
All solar equipment is to be attached to a SCH 40 steel pole (provided by
others). If concrete is used, ensure it has had adequate time to cure before
placing equipment on the pole. Refer to the Site Layout drawing in the
Appendix for details.
Solar Module Support Structure Assembly
Observe the following mounting and assembly guidelines:
- Refer to the structure assembly instructions included with the structure or the drawings in the Appendix.
- Generally the array tilt angle should be set to the site latitude plus 15° for optimum standalone performance. This is typically 55° for most of the United States.
- Align the structure to True South and adjust to the correct tilt angle.
System Enclosure Mounting
Using the (2) pole clamps provided, attach the system enclosure below the
solar module. The pole clamps slide into the slots in the enclosure mounting
brackets. Refer to the Site Layout drawing in the Appendix.
System Wiring
WARNING: Electrical Hazard
Photovoltaic modules generate high voltage whenever exposed to sunlight.
Voltages may be as high as 24 VDC depending on the models used.
CAUTION: Electrical Hazard
Ensure all fuses are removed and all circuit breakers are in the OFF position
before beginning any wiring.
NOTE: Wire Color Code
All pre-installed internal wiring uses the following color code unless
specified otherwise in this manual. RED (+ positive), BLACK (– negative),
GREEN or BARE (ground)
Grounding
The system enclosure should be grounded through the ground lug provided on the
bottom of the enclosure. Site grounding wire and hardware are to be provided
by others.
Array Wiring
Route the pre-wired Array cable(s) from the enclosure up the pole to the solar
module(s). Depending on module type; two conductors jacketed Tray Cable may be
used, or a pair of single conductor PV wires with MC4 style male/female
connectors. If a module interconnects wire is included, install it between the
modules first and connect as shown in the System Wiring Diagram.
For Tray Cable connections; route the cable into the module’s junction box and secure the cord grip, terminate the wires at the module’s terminal block. For PV wire MC4 wiring; at the module, connect the male and female MC4 connectors to the enclosure’s cables, ensuring the connectors seat fully. Refer to the System Wiring Diagram in the Appendix.
Load Wiring
If not pre-installed in the system enclosure, route cable or conduit (provided
by others) from the system enclosure to the load and secure/seal with an
appropriate connector. The LOAD terminal blocks accept up to #10 AWG wire.
Terminate the wires to the LOAD terminals and confirm proper polarity.
Terminate wiring at the loads as appropriate. Refer to the System Wiring
Diagram in the Appendix.
Battery Installation and Wiring
WARNING: Electrical Hazard
Batteries contain high discharge currents, use insulated tools on and around
batteries. Keep all battery wiring isolated from other wires or conductive
materials until all wires are connected.
WARNING: Chemical Hazard
Batteries contain sulfuric acid which can cause burns and another serious
injuries. In the event of contact with sulfuric acid, flush immediately and
thoroughly with water. The use of safety goggles, a rubber apron, and rubber
gloves is recommended.
WARNING: Explosive Hazard
Batteries can generate explosive gases, which when released, can explode and
cause blindness and another serious injury. Keep sparks, flames, and smoking
materials away from the battery area.
Place the battery in the enclosure and connect the battery cables to the
battery; Red to positive and Black to negative. If additional batteries are
used, installed in the same manner. Refer to the System Wiring Diagram &
Enclosure Layout in the Appendix.
System Checkout and Commissioning
At the end of the installation, it is important to confirm and verify all mechanical and electrical connections. Perform the following system checkout and complete the System Installation Checklist.
- Confirm the proper tilt angle and orientation of the solar array; ensure it is facing true south (and adjusted for magnetic declination if a magnetic compass is used).
- Ensure all mechanical fasteners are tight and secure.
- At the controller assembly, check the voltage and polarity of the battery. The voltage should be approximately 12.5 VDC.
- At the controller assembly, record the open circuit voltage (Voc) and short circuit current (Isc) of the array input. Confirm proper polarity.
- Switch ON the BATTERY circuit breaker (or install fuse). Switch on the ARRAY circuit breaker if present. Verify the green “CHARGING” indicator on the controller is lit. If it is not lit, go back and check the connections.
- Switch on the LOAD circuit breaker (if present), switch on the load(s) and verify its’ proper operation. Ensure the load is operating within the energy design of the system. If needed perform a series current draw.
SYSTEM INSTALLATION CHECKLIST AND START-UP DATA TABLE
- Array facing true south _____ (Yes/No)
- Array at correct tilt angle ____ (Yes/No)
- All mechanical fasteners tight _____ (Yes/No)
- Record the initial battery voltage at the controller.
- Battery ____ VDC
- Record the array open circuit voltage and short circuit current at the controller.
- Open Circuit Voltage __ VDC
- Short Circuit Current __ A
- Controller Operation:
- Charging LED illuminated _____ (Yes/No)
- Load Disconnect LED illuminated _____ (Yes/No)
- Load operating properly _____ (Yes/No)
INSTALLATION IS NOW COMPLETE
- Tested By: __ Date: _____
- Approved By: ____ Date: _____
RECOMMENDED MAINTENANCE
Although the solar electric power system should require minimal maintenance a few minutes time every 3-6 months can help to maintain the performance of the system and extend its service life.
Solar Array
The solar array should not need to be completely cleaned unless the dirt
build-up is particularly bad. Special care should be taken to look for and
remove any bird drops or mud as these essential shade the module and reduce
the output current. When cleaning the front surface of the array use a soft
non-abrasive cloth or brush and water. Avoid the use of any cleaning products
that may leave residue on the module or promote corrosion on the structure and
its’ fasteners.
Batteries
Inspect the battery for corrosion at the terminals and wire connections, clean
or replace terminals if they are damaged. Measure and record battery voltage.
System Wiring
Inspect all internal and external wiring for damage or corrosion at the system
enclosure, repair or replace as necessary. Re-tighten all accessible wiring
connections.
SYSTEM TROUBLESHOOTING
If the system is not functioning correctly, there are a few simple steps to isolate the problem. The following are some of the typical factors that contribute to the failure of the system to operate within design parameters:
- Load greater than system design – Installing loads greater than the system was designed for will reduce the performance of the system and damage the batteries. Excessive load operation can either be power, current or operating time. Daily load energy consumption should be checked to verify it is within the operating parameters of the system. If the load is greater than the system design, the load should be decreased or the system size increased (e.g. array, battery, controller, etc.)
- Shading – Even partial shading of the solar module can result in zero output from the module and will result in reduced system performance. Incorrect orientation or tilt angle – Refer to the installation instructions in Section 3 for proper orientation, alignment, and tilt adjustment. Incorrect alignment of the solar array will result in reduced array output and system performance.
- Battery failure may be caused by several factors: age, controller failure, or excessive load operation. If the battery is more than 5 years old is probably nearing the end of its’ service life and may need to be replaced. A capacity test can confirm the ability of the battery to support the load. If the battery is relatively new (1 to 2 years old) the system should be checked for proper operation by performing the System Checkout in section 3.6.
HARDWARE INCLUDED
OWNERSHIP
COPYRIGHT ©2012 THE ABOVE DRAWINGS, SPECIFICATIONS, IDEAS, DESIGNS, AND ARRANGEMENTS ARE ANO SHALL REMAIN THE PROPERTY OF AMERESCO ANO NO PART THEREOF SHALL BE COPIED, DISCLOSED TO OTHERS, OR USED IN CONNECTION WITH ANY WORK OR PROJECT OTHER THAN THE SPECIFIED PROJECT FOR WHICH THEY HAVE BEEN PREPARED ANO DEVELOPED WITHOUT THE WRITTEN CONSENT OF AMERESCO. VISUAL CONTACT WITH THESE PLANS OR SPECIFICATIONS SHALL CONSTITUTE CONCLUSIVE EVIDENCE OF ACCEPTANCE OF THESE RESTRICTIONS.
AMERESCO SOLAR CHANDLER, AZ
LANDSCAPE MODULE ORIENTATION SHOWN, FOR MODELS:
VLS-85W AND 490J.
- RAILS MUST BE FLIPPED INWARD AS SHOWN FOR 440J.
- PORTRAIT MODULE ORIENTATION IS SHOWN, FOR MODELS: VLS-SOW, 440J, 450J, AND 365J.