Fracsun CS4 User manual

ARES Soiling Measurement
System
Installation Manual
Model CS4
Revision F
Release date: August 17, 2021

ARES Soiling Measurement System
Installation Manual, revF
Page 2 of 15
Important Safety Instructions
WARNING: TO PREVENT FIRE, ELECTRIC SHOCK AND DAMAGE, DO NOT EXPOSE THE INTERNAL
COMPONENTS (CIRCUITS BOARDS AND WIRES) TO RAIN OR MOISTURE.
Please be aware of the safety instructions below:
1. Read these instructions.
2. Keep these instructions.
3. Follow all instructions.
4. Do not submerge the device(s) in water or liquid.
5. Do not install the ARES device directly on solar module frames.
6. Do not leave the ARES device powered on without sun (like indoors) for more than 24 hours. The battery
will fully discharge and may take more than 2 hours with full sun to recharge.
7. Never leave the Wash Extension solar panel glass facing down for an extended period of time.
8. Clean solar panel glass only with a damp microfiber cloth.
9. Tighten fasteners only as specified in this manual.
10. Do not pinch or sharply bend the flex plumbing tube. Doing so will result in inefficient spray and possible
pump failure.
11. Do not install next to heat sources such as inverters.
12. Do not connect any other solar panel to the Wash Extension other than the one supplied.
13. Consult Fracsun when any doubt or questions arise regarding equipment installation.
14. Refer all equipment servicing to qualified service personnel or Fracsun Inc.
Device Overview
The ARES Soiling Measurement System accurately measures the instantaneous
and daily soiling loss percentage by comparing the light generated current
difference between two identical reference cells. The ARES device contains a
“clean” reference cell which is cleaned daily while the “dirty” reference cell is left
to naturally soil. ARES is an Internet of Things (IoT) device and outputs data over
a 3G or 4G/LTE cellular network. ARES is powered by the sun and does not
require external power, making it deployable in virtually any location with a
cellular signal.
Accompanying the ARES device is the Wash Extension device, which automates
the washing events and provides feedback. The Wash Extension device can detect successful wash events, low tank
level, low battery, high humidity, and freezing conditions. ARES can be used without the Wash Extension device if it
is manually washed at fixed intervals.
Figure 1: ARES device

ARES Soiling Measurement System
Installation Manual, revF
Page 3 of 15
Box contents
The ARES soiling measurement system is shipped in two boxes. The following contents are in each box:
ARES box
ARES CS4 Soiling
Measurement Device
1x
External cellular whip antenna
(SMA connection)
1x
Flex tubing, 3 meter, 1/8” ID,
¼” OD (pre-attached to ARES)
1x
Wash Extension box
Gen3 Wash Extension device
(solar panel attached)
1x
Bottom support bracket
(attached to Wash Extension)
1x
M12 communication cable,
RS-485, 3 meters
1x
Corrugated sheathing, 3
meters
1x
Hardware Kit
1x
4x Threaded ground spike
4x 3/8”-16 x 1” hex head screw
3x Zip ties
1x Hose compression sleeve
Tools required
The following tools are required to install the ARES and Wash Extension devices.
Electric
screwdriver
*
PH2 bit
1/4" hex
drive bit
*
1/2" hex
socket
**
1/2"
wrench
**
3/16”
hex key
5/32”
hex key
* Required for Purlin Bracket Kit
** Required for HSAT Bracket Kit

ARES Soiling Measurement System
Installation Manual, revF
Page 4 of 15
Selecting a device location
Where to install
Measuring soiling is a new area of study for solar asset owners and operations teams. Every solar plant has a unique
soiling profile based on several environmental factors like dominant wind direction, agricultural activity, dirt roads,
mowing operations, pollen, wildfire ash, and air pollution. Knowing where to install soiling measurement stations, like
ARES, is a not a well-studied field and there is no single location that will capture an accurate soiling model of the
entire array. For this reason, it is beneficial to have multiple measurement locations within an array field to capture
non-uniform soiling phenomena and improve statistical significance of the soiling loss data.
The key is to install at locations on the array that are representative of the entire system, or the specific area that you
are studying. The pins in the image below show potential locations of ARES devices across a solar plant.
Figure 2: Potential ARES device locations across an entire solar plant.
Uniform or non-uniform soiling
Every site has a unique soiling profile. Often, due to local site conditions, soiling levels throughout a single array can
vary greatly. By creating measurement zones within a single array, the ARES device can empower a team to focus on
areas of highest soiling first.
Placement on the array
To generate a representative soiling loss value, the ARES device must be installed adjacent to the array in the same
tilt and orientation as the modules themselves. This is achieved by attaching the ARES unit to a structural component
of the racking system. This can be a torque tube, Z-purlin, aluminum module rack or any other member that matches
the array tilt. It is ideal to install the ARES hardware while the array is clean to achieve a matching baseline. This can
be achieved after a significant rain even or an array cleaning. If neither of these are possible nor convenient, the
ARES unit can be installed while taking note that the soiling loss measurement will not match. The daily accumulated
soiling loss (soiling rate) can still be used in the Fracsun portal to calculate an estimate of current soiling loss at the
site by extrapolating back to the most recent cleaning event.

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Installation Manual, revF
Page 5 of 15
Cellular signal
Depending on your model, ARES will operate on either a 3G or LTE CAT-M1 network. ARES must have decent signal
strength to successfully connect to a nearby cellular tower and communicate with the Fracsun cloud. A site survey is
highly recommended before installation.
A note on Modbus: If a cellular network is not available, ARES and Wash Extension devices can function as Modbus
RS-485 slave devices and stream data to a master device. However, a Modbus-only communication is not
recommended because of the loss of additional processing performed in the Fracsun cloud (like daily
soiling/insolation calculations, wash optimization schedules, and financials). The most flexible option to have data in
your DAS platform and the Fracsun cloud, is to use our RESTful API. Please contact Fracsun support to learn more
about Modbus-only communication or the API.
Site survey
There are several ways to perform a site survey for the best cellular connectivity. The most
convenient way is to use a smart phone on a AT&T or T-Mobile network. Verizon uses a
different carrier frequency, therefore will not work for performing a site survey. An Android
phone is recommended to perform the site survey if available. Apple devices have a built-in
“Field Test” mode that allows you to see the signal strength, which may or may not work on
certain iPhone versions. Apps on Android devices have many options, like selecting the carrier
frequency (3G or 4G/LTE) and visualizing the signal level on a gauge or a chart.
•Android devices: open the Play Store and download any of the following apps:
oNetwork Cell Info Lite by M2Catalyst, LLC.
oSignal Strength by Lakshman
•Apple devices: Open the call dialer and type in: *3001#12345#* to enter Field Test mode.
oGo to the “Serving Cell Measurements” page to view the Measured RSSI.
Signal strength
The device’s signal strength is in a “healthy” range when the RSSI is greater than -100 dBm (the closer to 0, the
stronger the signal). The signal quality, which measures relative noise in the connection, should be greater than 35%
(the closer to 100%, the better the quality). Both signal strength and quality impact the health of the connection. For
example, a site survey measuring an RSSI of -92 dBm at 45% quality would be “Fair” for the 3G band and “Good” for
the LTE CAT-M1 band, making it a good candidate for an install location.
3G Signal RSSI
3G Signal Quality
-70 dBm and greater
Excellent
-70 dBm to -85 dBm
Good
-86 dBm to -100 dBm
Fair
Less than -101 dBm
Poor
LTE CAT-M1 Signal RSSI
LTE Signal Quality
-90 dBm and greater
Excellent
-90 dBm to -105 dBm
Good
-106 dBm to -120 dBm
Fair
Less than -120 dBm
Poor
If the signal level cannot be measured, one can observe the download speed using an App like Ookla Speedtest to
determine if the signal quality is sufficient for installation at that prospective location. A general rule of thumb is if
you are achieving good download/upload speeds at the prospective location in the array, then it’s probably okay to
install.

ARES Soiling Measurement System
Installation Manual, revF
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Preparing the ARES device before mounting
Automatic wake in the sun
ARES devices are shipped in a deep-sleep mode state, which preserves the battery for up to 45 days while in the
box. When placed in the sunlight (specifically greater than 250 W/m2), ARES will wake from deep-sleep within 20
minutes (sometimes less) and start connecting to the nearest cellular tower. Once a connection is established, ARES
will begin normal operation.
This feature allows ARES to startup without opening the unit and connecting the internal battery. Just place ARES in
the sun, and it will power up.
Low battery
If more than 45 days has passed, the battery may be in a low-power state. If this occurs, give ARES at
least 20 minutes in full sun (or 40 minutes with clouds) to recharge the battery. Once the battery is at a
nominal level, ARES will automatically wake (if in the sun) and begin normal operation.
Mounting ARES to the array
Due to every array having unique mounting specifications, Fracsun has developed two universal mounts that will
work for the majority of tracking and fixed systems. The bottom of the ARES device contains six ¼-20 threaded
inserts that can be utilized to mount ARES in various methods if the universal mount will not fit your application. The
following examples explain how to mount ARES using the universal mounting hardware. If your team requires
assistance designing outside this hardware’s capabilities, please feel free to reach out to the Fracsun team.
Tracker torque tube using HSAT Bracket Kit
For the most representative measurement on a horizontal single axis tracking (HSAT) site, mounting ARES on an
available section of exposed torque tube is the best method. The HSAT Bracket Kit contains the hardware listed
below. In order to mount ARES to the torque tube, follow these instructions:
1. Determine the torque tube diameter and
insert the threaded rod into the
corresponding holes on the bottom of the
bracket.
2. Mount the bracket to the bottom of the ARES
device using the (2) ¼-20 x ½" flat head
screws. See Figure 3.
3. Place the ARES unit and the bracket on top of
the torque tube, ensuring it is parallel to the
plane of the modules.
4. Secure the bracket in place by attaching the
strut below the torque tube and securing with
(2) each of the 5/16” fender washer, locking
washer and finally the hex nut. See Figure 4.
Figure 3: Securing the HSAT bracket to the bottom of ARES.

ARES Soiling Measurement System
Installation Manual, revF
Page 7 of 15
HSAT bracket hardware list:
•(1) HSAT Bracket
•(2) 1/4-20 x ½" flat head screw
•(2) 5/16-18 threaded rod with locking nuts
•(1) 9” length shallow strut channel
•(2) 5/16” fender washers
•(2) 5/16” locking washers
•(2) 5/16”-18 hex nut
Fixed-tilt system using Purlin Bracket Kit
For fixed tilt systems, the Purlin Bracket Kit (PBK) is attached to a purlin or rail. ARES then mounts directly to this rail
if there is no correction needed to ensure the measurement plane is parallel to that of the array. The Purlin Bracket
Kit contains the hardware listed at the bottom of this section and is installed in the following steps:
1. Mount the angle bar to the racking using the self-tapping screws provided. Ensure that the ARES mounting
holes are aligned to the edge of the module so that the ARES unit sits flush to the module edge.
Note: the height from the top of module to the top of the bracket should measure 1.4”
2. Mount the ARES device using the ¼-20 button head screws to the bracket. See Figure 5.
Hardware list:
•(1) 18” Aluminum angle bar
•(2) #8 5/8” Hex head self-drilling screw, stainless steel
•(2) 1/4-20 x 1/2" bolts
•(2) 1/4”fender washers
•(2) 1/4” split-lock washers
Figure 4: Mounting ARES to the torque tube (not shown).
Figure 5: Mounting ARES to a purlin or rail using the Purlin Bracket Kit

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Installation Manual, revF
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External connections
SMA antenna connection
A gold-plated SMA RF connector is located on the bottom-side of ARES. The supplied
cellular di-pole whip blade antenna must be threaded onto the SMA connector to
send/receive cellular data. If the antenna is not connected, ARES will not output data or
functional properly.
The antenna is omni-directional with uniform power in all directions. The optimum
antenna orientation for highest signal power and quality is straight (not bent), as seen
in Figure 6.
Note: If the SMA connector is not there, an internal antenna is attached inside ARES.
M12 connection
The M12 circular receptacle is located on the bottom-side of ARES. This connection is normally used to connect the
ARES and Wash Extension devices together for internal communication purposes. If a Wash Extension was supplied
with your ARES device, connect the supplied M12 cable assembly between the two devices.
Orient and insert the cable into the M12 receptacle and gently rotate the metal ring until locked in place. Do not
overtighten .
(Optional) Modbus RTU master / datalogger / SCADA system
By default, the ARES device is configured as a self-powered IoT cellular device, without any external Modbus RTU
connection required. The device turns on, takes a few measurements, sends the data to the cloud, and then goes
into a low-power sleep state to maintain optimal battery voltage.
Modbus-only mode
When a more robust Modbus connection is required, a different mode (Modbus-only mode) can be enabled.
Modbus-only mode turns off the internal cellular modem and disables all mobile connectivity. This mode is helpful in
locations without cellular signal or mandatory NERC compliance. Modbus-only mode will bypass the low-power sleep
state and cellular cloud functions, but the microcontroller will always remain ON to be available for Modbus polling.
Please contact Fracsun to learn more about connecting ARES to a Modbus RTU master, datalogger, or SCADA
system.
Figure 6: Blade antenna
oriented straight and
connected to SMA connector
Figure 7: M12 circular connection on the ARES botom side

ARES Soiling Measurement System
Installation Manual, revF
Page 9 of 15
Wash Extension Installation
Rinsing fluid
Fluid type
The wash extension can hold up to 16 gallons of rinsing fluid. The fluids list below are highly
recommended for high soiling accuracy. Under no circumstances should tap water be used. Tap water
contains minerals that will build up on the solar glass after each wash, affecting the irradiance
measurement and soiling accuracy.
•Distilled water
•Filtered water (RO + DI preferred) with a TDS (total dissolved solids) value of less than 20
Number of days
Each rinse uses roughly 5 ounces of water per spray, allowing for about 360 rinses. A future firmware update to
ARES devices will disable rinse events on rainy days, reducing the tank refill frequency.
Low tank alert
A liquid level sensor is installed inside the 16 gallon tank. When the sensor is triggered, a “low tank alert” is sent to
the Fracsun cloud and you will receive an update via Email and the Web Portal. You will have approximately 60 days
to refill the tank before it is completely dry. If rinsing does not occur, the soiling accuracy will be in jeopardy.
Where to install the Wash Extension
The Wash Extension needs to be installed on the ground (or roof) adjacent to the ARES hardware. The equipment
includes 8 feet of flex tube and communication cable for this purpose. Best practices include installing a service loop
along this length to prevent water from the system flowing against the connections to the enclosure.
Ground application using the bottom support bracket
If installing into dirt, the threaded ground spikes will both lift the
Wash Extension above the ground and allow leveling of the unit. If
the ground is soft enough the bracket can be attached first and the
whole unit can be pressed into the ground and leveled while
assembled, from the top. If the soil is compact and difficult to drive
into, the bracket can be hammered into place and leveled before
placing the tank on top.
Roof application
For roof mounted systems, leave the mounting bracket off and place the Wash Extension directly on the roof thereby
spreading the weight more evenly. Use of slip sheets is recommended to prevent unwanted wear to the roof
membrane.
The net weight of the Wash Extension is 161 pounds when full and has a contact area of 1.92 ft2. The equates to a
structural roof dead load of 83.85 psf. This can be mitigated by partially filling the tank, though this will require more
refilling than the designed annual schedule. Always ensure that the loading capacity of the roof will meet the
demands of the Wash Extension.
Figure 8: Wash Extension bottom support bracket
and ground spikes

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Installation Manual, revF
Page 10 of 15
Removing the solar panel
To continue with installation, the solar panel must be removed to gain access
to the Wash Extension enclosure cover, M12 connection, and pump output
barb. Remove the 4 machine screws (2 per side) as seen in Figure 9 and set
the solar panel aside.
The machine screws are #12-24 x 3/8” L, pan head Phillips.
Connecting the flex tubing and communication cable
To enable the daily automatic cleaning and feedback, the included flex tubing and M12 communication cable must be
connected between the Wash Extension and ARES device.
Note: When routing flex tube and cabling, uncoil both to avoid any kinks.
1. Carefully route the flex tubing from ARES to the Wash Extension. By
default, the tube is attached to the ARES unit.
2. Insert the compression sleeve onto the Wash-Extension end of the tube.
This sleeve must be connected before installing the tube onto the barb.
3. Push the tube onto the barb, ensuring full coverage over the barb.
4. Move the compression sleeve up the tube and over the barb. Use a 11/32”
wrench to tighten the sleeve in a clock-wise direction until secure. See
Figure 10 which shows a tight connection.
5. Connect the M12 communication cable to the Wash Extension using the
following steps:
a. Fully insert the connector into the receptacle in the proper
orientation. See Figure 11.
b. Rotate the metal bayonet ring clockwise until it locks. See Figure 12.
6. If not already performed, connect the M12 communication cable to the ARES device following the same
steps above to secure the cable.
7. Wrap the provided 3 meter corrugated sheathing around both the flex tube and communication cable.
Gently tighten zip ties at the start and end of the corrugated sheathing. See Figure 13.
Figure 11: M12 cable and receptacle
before connection
Figure 12: Locked M12 cable inside
receptacle. Cable and tube go to ARES.
Figure 13: Corrugated sheathing
covering M12 cable and tubing
Figure 10: Flex tube connection
Figure 9: Remove the solar panel by
removing these machine screws.