Campbell CH201 User manual

06/2020
Copyright © 2020
Campbell Scientific
CSL I.D - 1352

Guarantee
This equipment is guaranteed against defects in materials and workmanship.
We will repair or replace products which prove to be defective during the
guarantee period as detailed on your invoice, provided they are returned to us
prepaid. The guarantee will not apply to:

Equipment which has been modified or altered in any way without the
written permission of Campbell Scientific

Batteries

Any product which has been subjected to misuse, neglect, acts of God or
damage in transit.
Campbell Scientific will return guaranteed equipment by surface carrier
prepaid. Campbell Scientific will not reimburse the claimant for costs incurred
in removing and/or reinstalling equipment. This guarantee and the Company’s
obligation thereunder is in lieu of all other guarantees, expressed or implied,
including those of suitability and fitness for a particular purpose. Campbell
Scientific is not liable for consequential damage.
Please inform us before returning equipment and obtain a Repair Reference
Number whether the repair is under guarantee or not. Please state the faults as
clearly as possible, and if the product is out of the guarantee period it should
be accompanied by a purchase order. Quotations for repairs can be given on
request. It is the policy of Campbell Scientific to protect the health of its
employees and provide a safe working environment, in support of this policy a
“Declaration of Hazardous Material and Decontamination” form will be
issued for completion.
When returning equipment, the Repair Reference Number must be clearly
marked on the outside of the package. Complete the “Declaration of
Hazardous Material and Decontamination” form and ensure a completed copy
is returned with your goods. Please note your Repair may not be processed if
you do not include a copy of this form and Campbell Scientific Ltd reserves
the right to return goods at the customers’ expense.
Note that goods sent air freight are subject to Customs clearance fees which
Campbell Scientific will charge to customers. In many cases, these charges are
greater than the cost of the repair.
Campbell Scientific Ltd,
80 Hathern Road,
Shepshed, Loughborough, LE12 9GX, UK
Tel: [phone]
Fax: [phone]
Email: [e-mail]
www.campbellsci.co.uk

PLEASE READ FIRST
About this manual
Please note that this manual was originally produced by Campbell Scientific Inc. primarily for the North
American market. Some spellings, weights and measures may reflect this origin.
Some useful conversion factors:
Area: 1 in2(square inch) = 645 mm2
Length: 1 in. (inch) = 25.4 mm
1 ft (foot) = 304.8 mm
1 yard = 0.914 m
1 mile = 1.609 km
Mass: 1 oz. (ounce) = 28.35 g
1 lb (pound weight) = 0.454 kg
Pressure: 1 psi (lb/in2) = 68.95 mb
Volume: 1 UK pint = 568.3 ml
1 UK gallon = 4.546 litres
1 US gallon = 3.785 litres
In addition, while most of the information in the manual is correct for all countries, certain information
is specific to the North American market and so may not be applicable to European users.
Differences include the U.S standard external power supply details where some information (for
example the AC transformer input voltage) will not be applicable for British/European use. Please note,
however, that when a power supply adapter is ordered it will be suitable for use in your country.
Reference to some radio transmitters, digital cell phones and aerials may also not be applicable
according to your locality.
Some brackets, shields and enclosure options, including wiring, are not sold as standard items in the
European market; in some cases alternatives are offered. Details of the alternatives will be covered in
separate manuals.
Part numbers prefixed with a “#” symbol are special order parts for use with non-EU variants or for
special installations. Please quote the full part number with the # when ordering.
Recycling information
At the end of this product’s life it should not be put in commercial or domestic refuse but
sent for recycling. Any batteries contained within the product or used during the
products life should be removed from the product and also be sent to an appropriate
recycling facility.
Campbell Scientific Ltd can advise on the recycling of the equipment and in some cases
arrange collection and the correct disposal of it, although charges may apply for some
items or territories.
For further advice or support, please contact Campbell Scientific Ltd, or your local agent.
Campbell Scientific Ltd, 80 Hathern Road, Shepshed, Loughborough, LE12 9GX,
UK Tel: [phone] Fax: [phone]
Email: [e-mail]
www.campbellsci.co.uk

Safety
DANGER —MANY HAZARDS ARE ASSOCIATED WITH INSTALLING, USING, MAINTAINING, AND WORKING ON
OR AROUND TRIPODS, TOWERS, AND ANY ATTACHMENTS TO TRIPODS AND TOWERS SUCH AS SENSORS,
CROSSARMS, ENCLOSURES, ANTENNAS, ETC. FAILURE TO PROPERLY AND COMPLETELY ASSEMBLE,
INSTALL, OPERATE, USE, AND MAINTAIN TRIPODS, TOWERS, AND ATTACHMENTS, AND FAILURE TO HEED
WARNINGS, INCREASES THE RISK OF DEATH, ACCIDENT, SERIOUS INJURY, PROPERTY DAMAGE, AND
PRODUCT FAILURE. TAKE ALL REASONABLE PRECAUTIONS TO AVOID THESE HAZARDS. CHECK WITH YOUR
ORGANIZATION'S SAFETY COORDINATOR (OR POLICY) FOR PROCEDURES AND REQUIRED PROTECTIVE
EQUIPMENT PRIOR TO PERFORMING ANY WORK.
Use tripods, towers, and attachments to tripods and towers only for purposes for which they are designed. Do not
exceed design limits. Be familiar and comply with all instructions provided in product manuals. Manuals are
available at www.campbellsci.eu or by telephoning [phone] (UK). You are responsible for conformance
with governing codes and regulations, including safety regulations, and the integrity and location of structures or land
to which towers, tripods, and any attachments are attached. Installation sites should be evaluated and approved by a
qualified engineer. If questions or concerns arise regarding installation, use, or maintenance of tripods, towers,
attachments, or electrical connections, consult with a licensed and qualified engineer or electrician.
General
•Prior to performing site or installation work, obtain required approvals and permits. Comply with all
governing structure-height regulations, such as those of the FAA in the USA.
•Use only qualified personnel for installation, use, and maintenance of tripods and towers, and any
attachments to tripods and towers. The use of licensed and qualified contractors is highly recommended.
•Read all applicable instructions carefully and understand procedures thoroughly before beginning work.
•Wear a hardhat and eye protection, and take other appropriate safety precautions while working on or
around tripods and towers.
•Do not climb tripods or towers at any time, and prohibit climbing by other persons. Take reasonable
precautions to secure tripod and tower sites from trespassers.
•Use only manufacturer recommended parts, materials, and tools.
Utility and Electrical
•You can be killed or sustain serious bodily injury if the tripod, tower, or attachments you are installing,
constructing, using, or maintaining, or a tool, stake, or anchor, come in contact with overhead or
underground utility lines.
•Maintain a distance of at least one-and-one-half times structure height, or 20 feet, or the distance
required by applicable law, whichever is greater, between overhead utility lines and the structure (tripod,
tower, attachments, or tools).
•Prior to performing site or installation work, inform all utility companies and have all underground utilities
marked.
•Comply with all electrical codes. Electrical equipment and related grounding devices should be installed
by a licensed and qualified electrician.
Elevated Work and Weather
•Exercise extreme caution when performing elevated work.
•Use appropriate equipment and safety practices.
•During installation and maintenance, keep tower and tripod sites clear of un-trained or non-essential
personnel. Take precautions to prevent elevated tools and objects from dropping.
•Do not perform any work in inclement weather, including wind, rain, snow, lightning, etc.
Maintenance
•Periodically (at least yearly) check for wear and damage, including corrosion, stress cracks, frayed cables,
loose cable clamps, cable tightness, etc. and take necessary corrective actions.
•Periodically (at least yearly) check electrical ground connections.
WHILE EVERY ATTEMPT IS MADE TO EMBODY THE HIGHEST DEGREE OF SAFETY IN ALL CAMPBELL
SCIENTIFIC PRODUCTS, THE CUSTOMER ASSUMES ALL RISK FROM ANY INJURY RESULTING FROM IMPROPER
INSTALLATION, USE, OR MAINTENANCE OF TRIPODS, TOWERS, OR ATTACHMENTS TO TRIPODS AND TOWERS
SUCH AS SENSORS, CROSSARMS, ENCLOSURES, ANTENNAS, ETC.

Table of contents
1. Introduction 1
2. Precautions 1
3. Initial inspection 3
4. Overview 3
4.1 Communications interface 5
5. Specifications 6
6. Installation 8
6.1 Connect to power source 10
6.1.1 Solar panel 10
6.1.2 DC power 11
6.2 Connect to battery 11
6.3 Connect to data logger 11
6.4 (Optional) Connect to data logger for SDI-12 or RS-232 communications 12
6.5 Turn on power source 12
6.6 Turn on CH201 12
6.7 (Optional) Configure using Device Configuration Utility 12
6.7.1 Battery families and capacity 15
7. Operation 19
7.1 Charging algorithm 19
7.2 Maximum power point tracking 20
7.3 Communications 21
7.3.1 SDI-12 communications 23
7.3.1.1 SDI-12 commands 24
7.3.1.2 CRBasic programming 25
7.3.2 RS-232 communications 25
7.3.2.1 RS-232 commands 27
7.3.2.2 CRBasic programming 29
7.4 LED indicators 29
8. References 30
Table of Contents - i

Appendix A. Downloading an operating system 31
Table of Contents - ii

1. Introduction
The CH201 is a charging regulator for an external rechargeable 12V VRLA, valve-regulated lead-
acid, battery, such as the BP12 or BP24 offered by Campbell Scientific. Charging power for this
charging regulator is typically supplied by an unregulated solar panel or AC-to-DC converter.
The CH201 is a smart charger that provides a programmable low voltage disconnect and two-step
constant voltage charging with temperature compensation for optimal charging and battery life.
A maximum power point tracking algorithm is incorporated for solar inputs to maximize available
solar charging resources.
The CH201 is a series regulator, which has the regulator placed, in series, between the charging
source and the load. As batteries become closer to fully charged, series regulators reduce the
current drawn from the charging source. The charging source may be completely unloaded if full
charge is reached. Charging source unloading is acceptable for solar panels and AC-to-DC
converters. For wind turbines, charging source unloading can cause free spinning. Consequently,
do not use series charging regulators, such as the CH201, to regulate wind-turbine outputs
without a method to load the turbine when the batteries require little or no charging current.
The CH201 has several safety features that protect the charging source, battery, charger, and load
devices. Both the DC In 1 and DC In 2 input terminals have polarity reversal protection and
programmable hardware current limits. The CH201 has a programmable maximum battery
charging current limit. A self-resettable, thermal fuse is in-series with the 12 VDC output
terminals to protect the charger from an output load fault. The CH201 includes battery reversal
protection, and ESD and surge protection are incorporated on all inputs and outputs.
2. Precautions
Only use the following battery cables with the CH201: pn#34029, pn#34031, pn#34040,
and pn#36589.
Overcharging VRLA batteries can produce excess hydrogen and oxygen gases, and the
accumulation of hydrogen gas can form an explosive mixture. Fortunately, hydrogen gas is
difficult to contain in anything but a metal or glass enclosure.
CH201 12V Charging Regulator 1

DANGER:
Never house VRLA batteries in an enclosure that does not allow dispersion of emitted
hydrogen gas.
When using a current limiting power supply such as a AC-to-DC converter, change the input
current limit using the Device Configuration Utility to prevent the CH201 from pulling more
current than what is available, thus tripping current limit protection of the converter.
VRLA batteries can provide high-surge currents. A 4.6A solid-state circuit breaker protects the
12VDC output terminals, but there is no fusing for inadvertent bridging of the battery terminals.
DANGER:
Accidental shorting of battery terminals by metallic objects, such as watchbands, can cause
severe burns due to rapid heating and is also a fire hazard.
VRLA battery manufacturers state that “Heat Kills Batteries.” While the operating temperature
range is –40 to 60°C, optimum battery life occurs in the 5 to 35°C temperature range1. The
CH201 offers temperature compensation of the battery charging voltage based on a temperature
measurement inside the CH201 case. The CH201 internal temperature measurement only
accurately represents battery temperature for charge voltage compensation if the battery is next
to the CH201. To overcome temperature differences, use the CH201 serial interface to input an
independently measured battery temperature for improved charging temperature compensation.
With rechargeable batteries, a charge →discharge →recharge event is termed a cycle. In
general, the most important factor for the battery service life is depth of discharge1. For example,
decreasing the depth of each discharge from 100% to 50% approximately doubles the number of
useful cycles available from the battery1.
WARNING:
Leaving a lead-acid battery in a discharged state for prolonged periods causes large sulfate
crystals (sulfation) that are detrimental to battery performance.
VRLA batteries self-discharge at approximately 3% of rated capacity per month at room
temperature1. A 3% of rated capacity per month self-discharge results in 100% discharge in
approximately 33 months for a battery stored at room temperature. The battery self-discharge
rate increases with higher storage temperatures.
1Genesis Application Manual – Genesis NP and NPX Series US-NP-AM-002, June 2006.
CH201 12V Charging Regulator 2

WARNING:
Every few months, recharge stored batteries to prevent irreversible sulfation due to prolonged
time in a discharged state.
3. Initial inspection
Upon receipt of the CH201, inspect the packaging and contents for damage. File damage claims
with the shipping company.
4. Overview
FIGURE 4-1 (p. 4) provides a simplified schematic of the CH201 charging regulator. See Table 5-1
(p. 7) for rechargeable batteries offered by Campbell Scientific.
CH201 12V Charging Regulator 3

FIGURE 4-1. CH201 schematic
An unregulated solar panel or AC-to-DC converter typically supplies charging power to the
CH201. As shown in FIGURE 4-1 (p. 4), diodes connected to the two DCIn terminals provide input
reversal protection and isolation between power sources. DCIn terminals have a polarity that
must be followed. Connect the positive wires to the DCIn terminals, and connect the negative
wires to the Gterminals. Reversed polarity inputs, however, will NOT damage the CH201. The
DCIn input terminals have an input current limit of approximately 10amps, making the CH201
well suited for 170watt or smaller solar panels. Higher powered solar panels may not damage the
CH201, but the additional power likely won't be fully used. Additionally, each input has a
programmable current limit. See (Optional) Configure using Device Configuration Utility (p. 12).
Internal diodes route power from the source with the highest input voltage. An AC-mains-
powered application can use a solar panel for back-up if the AC-to-DC source has a higher
CH201 12V Charging Regulator 4

voltage than the solar panel. The solar power will be the primary supply and AC will be the
secondary supply if the solar panel has a higher output voltage than the AC-to-DC source.
The 12V output terminals are for powering a data logger and peripherals. A toggle switch
controls power to these output terminals. The total output current is limited by a 4.6A solid-state
circuit breaker.
Each battery family uses a unique charging algorithm to calculate the best charging voltage for
battery temperature. The algorithms use the charger temperature as the default temperature
source. If the charger and battery are in the same enclosure, the two temperatures will be similar.
If the battery will be in a separate enclosure, place a temperature sensor on or near the battery
and use the appropriate SDI-12 or RS-232 command to send this temperature to the module (see
Table 7-4 (p. 25) and Table 7-6 (p. 27)).
The CH201 has two LED indicators, the CHG (charge) LED and the CKBAT (check battery) LED.
Table 7-7 (p. 30) and Table 7-8 (p. 30) list the conditions and associated colours for the CHG and
CKBAT LEDs.
The CH201 communicates using a data logger or computer COM port. Data logger
communications can be done using SDI-12 or RS-232 as indicated in FIGURE 7-3 (p. 23) and
FIGURE 7-4 (p. 26). See Communications (p. 21) for details.
4.1 Communications interface
The CH201 can send data to the user to observe and manage power requirements and possible
problems. It can also be configured to work with a wide range of batteries and input power
supplies and test the existing battery system for possible shorting and sulfation problems.
The CH201 can be used without any configuration or communications. To take advantage of the
additional features of the CH201, however, the CH201 supports three kinds of communications:
lCommunications to a computer running Device Configuration Utility. This utility simplifies
configuration of the CH201 and allows for operating system updates. Device Configuration
Utility may be downloaded free of charge at www.campbellsci.eu/downloads. See
(Optional) Configure using Device Configuration Utility (p. 12).
lSDI-12 communications as an SDI-12 sensor according to the SDI-12 standard
(www.SDI-12.org). See SDI-12 communications (p. 23) for an in depth explanation.
lRS-232 communications to a data logger or computer. See RS-232 communications (p. 25)
for an in-depth explanation.
SDI-12 data logger programming is usually simpler than RS-232 programming. Also, multiple
SDI-12 sensors can share a single data logger control or universal terminal if they have unique
CH201 12V Charging Regulator 5

SDI-12 addresses; RS-232 devices are limited to one device per terminal. The advantage of RS-232
is its speed can be faster than SDI-12.
All CH201 serial communications use three COM terminals, TX,RX, and G. The CH201 will detect
the mode of communications and will reconfigure itself accordingly.
FIGURE 4-2. CH201 COM terminals
5. Specifications
Operational Temperaturea:–40 to 60 °C
Dimensions: 11.40 x 10.08 x 3.38 cm (4.49 x 3.97 x 1.33 in)
SOLAR Terminals (Solar Panel
or Other DC Source)b
Input Voltage Range: 15 to 50VDC
Maximum Charging Current: 10 A
Power Out (+12 terminals)
Voltage: Unregulated 12 V from battery
4.6 A solid state circuit breaker. Self-resettable thermal.
Battery Chargingc
CYCLE Charging: Vbatt(T) = 14.70 V – (24 mV) • (T – 25 °C)
FLOAT Charging: Vbatt(T) = 13.65 V – (18 mV) • (T – 25 °C)
CH201 12V Charging Regulator 6

Measurements
Input Voltage: ±(1% of reading +15 mV)
Battery Voltage: ±(2% of reading +15 mV)
Load Currentd:±(2% of reading +2 mA)
Battery Currentd:±(2% of reading +10 mA)
Charger Temperature: ± 2 °C
Quiescent Current
No Charge Source Present: 300 μA maximum
No Battery Connected: Typical 5 mA at 40 VDC
Compliance: View the EU Declaration of Conformity at
www.campbellsci.eu/CH201
aVRLA battery manufacturers state that “heat kills batteries” and recommend operating batteries at temperatures
below 50 °C.
bBattery voltages below 8.7 V may result in <3.0 A current limit because of fold-back current limit.
cTwo-step temperature compensated constant-voltage charging for valve-regulated lead-acid batteries. Cycle and
float charging voltage parameters are programmable with the default values listed.
dImpulse-type changes in current may have an average current measurement error of ±(10% of reading + 2 mA).
Table 5-1: Available Campbell Scientific battery packs
Battery Pack Model Amp-Hour Capacity
(Ah)
Operating
Temperature Range1
(ºC)
Battery Family
BP7 7 Charge: –15 to 50
Discharge: –20 to 60 EnerSys/Genesis
BP12 12 Charge: –15 to 50
Discharge: –20 to 60 EnerSys/Genesis
BP24 24 Charge: –15 to 50
Discharge: –20 to 60 EnerSys/Genesis
BP84 84 –40 to 71 Concorde Sun Xtender
1Battery specifications are from the manufacturer. The CH201 contains charging algorithms that optimize battery
charging over the range of –40 to 60 °C. Battery usage outside of manufacturer specifications could have unknown
effects on the life of the battery.
CH201 12V Charging Regulator 7

WARNING:
Battery life is shortened if the battery is allowed to discharge below 11.5 VDC. Low voltage
disconnect can be set in the CH201. Default low voltage disconnect is 6 VDC.
Charging requirements and tips:
Campbell Scientific offers a variety of solar panels and AC-to-DC transformers to meet the power
requirements of a system installation.
l10 A is the highest input current that the CH201 can fully use. Although a solar panel or
transformer with a higher output current won't damage the CH201, its power will not be
fully used. Peak voltage of the solar panel must be less than 50VDC.
lSolar panel specifications assume a 1 kilowatt per square meter illumination and a solar
panel temperature of 25°C (77°F).
lIndividual solar panels may vary up to 10%.
lSolar panel output voltage increases as the panel temperature decreases. VRLA batteries
also have increased output voltage as the battery temperature decreases.
lHigher latitudes and less sun hours during winter months might require a larger solar panel
than what is required to keep the battery charged during the summer.
lUse the Device Configuration Utility to change the current limit settings of DC In 1 or DC
In2 to accommodate the current limit of a charging source. For example, set the current
limit to 1.67 A to avoid tripping the power supply when using a wall charger with a 1.67 A
current limit.
DCIn terminals have a polarity that must be followed. Connect the positive wires to the DCIn
terminals, and connect the negative wires to the Gterminals. Reversed polarity inputs, however,
will NOT damage the CH201.
6. Installation
The CH201 module is designed to handle extreme conditions and to transmit charging, load, and
battery voltage and current information directly to a data logger by using SDI-12 or RS-232
commands. The data logger program can use the CH201 data to calculate a power budget for the
system and remotely pinpoint power problems. SDI-12 or RS-232 connections are not required for
normal operation, and the module is ready to use out of the box.
CH201 12V Charging Regulator 8

The CH201 has mounting holes on one-inch centres for mounting to a standard Campbell
Scientific enclosure backplate—see the enclosure manual for mounting suggestions. See FIGURE
6-1 (p. 9) for a typical enclosure installation using a CH201.
NOTE:
By default, the CH201 module is programmed with a battery capacity of zero amp-hours (Ah).
This sets the charger to charge at a lower current rate. A battery capacity must be configured
into the CH201 to enable the more aggressive two-step constant voltage charging scheme.
See Battery families and capacity (p. 15) for making changes by using Device Configuration
Utility. A downloadable example program using SDI-12 to set the battery capacity is available
at www.campbellsci.eu/downloads/ch201-program-examples.
FIGURE 6-1. CH201 configured for SDI-12 communications
The installation section discusses the following:
6.1 Connect to power source 10
6.2 Connect to battery 11
CH201 12V Charging Regulator 9

6.3 Connect to data logger 11
6.4 (Optional) Connect to data logger for SDI-12 or RS-232 communications 12
6.5 Turn on power source 12
6.6 Turn on CH201 12
6.7 (Optional) Configure using Device Configuration Utility 12
6.1 Connect to power source
DANGER:
Although the power supply and battery are low voltage, they can heat a metal ring,
watchband, or bracelet enough to burn skin or melt metal when shorted. Remove rings,
watches, or bracelets before hooking up power and connecting a battery.
Unlike the CH200, the CH201 has two DC inputs instead of one AC and one DC input. A solar
panel or AC-to-DC converter can connect to either input terminal. If both CH201 inputs are
connected to power sources, the power source with the highest voltage will supply power to the
CH201. Therefore, two solar panels can face different directions to allow the solar panel facing
the most direct sunlight to power the CH201.
Toggle the power supply switch to Off before connecting power to the CH201.
NOTE:
The switch on the CH201 only controls power going to the 12V terminals. The battery is
continuously charged regardless of the switch position when charging voltage is present.
6.1.1 Solar panel
WARNING:
To prevent sparking while wiring the solar panel, lay the solar panel face down on its packing
box or cover it with something to block the sunlight while wiring up the panel.
Connect the black (negative) wire from the solar panel to the G terminal that is adjacent to the
DCIn1 or DCIn2 terminal. Connect the red (positive) wire from an unregulated solar panel to
the DCIn1 or DCIn2 terminal. See FIGURE 6-2 (p. 11).
CH201 12V Charging Regulator 10