Power Supplies
Batteries, Solar Panels, ac Chargers
Campbell Scientific's (CSI) data acquisition systems are powered by reliable, inexpensive 12 Vdc sources.*
Power consumption by our dataloggers, peripherals, and sensors is minimal, allowing extended operation from
our standard sealed rechargeable battery or set of alkaline cells. Systems that require more power can be supplemented with external rechargeable batteries, regulators, and charging sources (ac power or solar panels). The
diagram below depicts the interaction of the components in a power supply system.
Charging Source
- Solar Panel
- AC Power
Rechargeable Battery
- Sealed (Internal)
- User-supplied (External)
Regulator
and/or
Alkaline Batteries
Data Acquisition System
- Datalogger
- Sensors
- Peripheral Equipment
- Multiplexers
- SDMs
- Communication Devices
Calculating Power Consumption
The system's power consumption can be approximated by calculating the average current required by the datalogger, sensors, and peripheral equipment (multiplexers, SDMs, and communication devices). This average current drain is primarily determined by the percentage of time spent in an "active" versus "quiescent" state, which
can be approximated from the datalogger's scan rate (Execution Interval) and the program length. Please note
that short scan rates dramatically affect average current drain (see graph below).
CR10X
CurrentDrain
Drain
CR10
Current
Typical
Weather Station Program
Typical Weather Station Program
9
7
Average current drain (mA)
Equivalent Continuous Current Drain mA
8
6
5
4
3
2
1
0
1
3
2
5
4
7
6
9
8
11
13
15
17
19
21
23
25
27
29
10
12
14
16
18
20
22
24
26
28
30
CR10 Scan
CR10X
ScanRate
Rate(seconds)
(seconds)
*This brochure briefly describes the equipment available to power CSI data acquisition systems. For more information, please download a copy of our
Power Supply Application Note from our Web site.
In applications where the scan rate is in excess of 30 seconds, the datalogger's average current drain approaches
the quiescent drain. For example, a CR10X-based weather station measuring standard meteorological sensors at
a thirty second (30 s) scan rate has an average current drain of:
State
Analog Measurement:
Processing:
Quiescent:
Duration (s)
0.2
0.03
29.77
Current
Drain (mA)
46
13
1.3
CR10X's Average = (0.2 s)(46 mA) + (0.03 s)(13 mA) + (29.77 s)(1.3 mA)
= 1.61 mA
Current Drain
30 s
Communication with the station for data retrieval, monitoring, or program transfer also consumes power as the
datalogger goes into a processing state, and activates the communication device. To conserve power, Campbell
Scientific's modem devices are active only during communication.
For example, if the station is called once a day (1440 min) for 5 minutes via telephone (COM200 modem), the
current drain is:
State
Active:
Quiescent:
Duration (min)
5
1435
Current Drain =
Current Drain (mA)
140(COM200) + 13 (CR10X) = 153
0.1
(5 min)(153 mA) + (1435 min)(0.1 mA)
(1440 min)
= 0.63 mA
Assuming negligible power consumption by the meteorological sensors, the system's average current drain is:
1.61 mA + 0.63 mA = 2.24 mA or 0.00224 A
Batteries
Alkaline Batteries
INTERNA
L BATTER
Y
BPA
TEMPOR
ARY BAT
TERY
12V AL
LK
KALINE
Logan
BATTER
Y PACK
Pa
n
alin
on
as
nn
AG G
G
AG G
G
alin
Pa
L AG
E3
Alk
e
alin
Alk
12
e
D
6
D
SW 12V
CTRL
SW 12V
G
SE
DEF
EARTH
CROUND
1
G G
1
H
2
3
L AG
H
2
4
5
L AG
H
3
L AG
E3
G 12V
POWE
R
IN
SERIAL I/O
CR10X
WIRING
PANEL
MADE IN
USA
6
AG G
G G
H
L AG
H
Eight "D" cell alkaline batteries power the CR510, CR500, CR10(X), and 21X
dataloggers; ten power the CR23X. These batteries are NOT rechargeable.
The alkaline batteries have a nominal rating of 7.5 Ahrs at 20°C; the amp
hour rating decreases with temperature extremes. Alkaline batteries may
leak when used outside the temperature range of -25° to +50°C. Allowing
the battery voltage to drop below 9.6 V can also cause leakage.
D
11
L AG
H
e
10
alin
5
Pa
nn
as
on
ic
9
L AG
H
c
8
Alk
D
ni
4
H
so
7
na
UTAH
G G
ic
e
LOGAN,
USA
Alk
Pa
nn
as
on
ic
MADE IN
SE
DEF
, Utah
L AG
H
SDM
L AG E3
12V 12V
WIRING
PANEL
NO.
CR10X
MEASUREMEN
T AND CONTROL
MODULE
firmware C 1983,
1986, 1995
For the above weather station with a system current drain of 0.00224 A, the
alkaline batteries theoretically last:
(7.5 Ahrs)/(0.00224 A) ≅ 3348 hours or about 140 days
S/N: X 1012
In practice, we suggest monitoring battery voltage to determine actual
replacement time.
The BPALK power supply (exploded view shown) uses eight “D” cell
batteries to power the CR10X
(shown), CR10, CR510, or CR500.
Both units shown mounted in an
ENC 12/14 enclosure.
Datalogger’s Sealed Rechargeable Batteries
WITH
POW
12V CHA
ER SU
PP
RGING
REGULA
LY
WARN
ING
TOR
:
PERM
ANEN
T DAM
CELLS
MAY RESUAGE TO
RECH
BELO
LT
ARGE
W 10.5
ABLE
VOLTS IF DISCARGE
D
FUNCTIO
N
Logan
, Utah
BAT
INT
EXT
OFF
ON
CHG
MADE IN
CHG
CHG
+12
+12
USA
PS12 BATTER
Y
EXTER
NAL BATTER
INTERN
AL RECHA Y - DO NOT
USE
POWER
RGEAB
LE BATTERWITH
TO +12
TERMIN
INPUT
Y
ALS
FROM
16-26 VDC CHARG
ER OR
SOLAR
EITHER OR AC
POWER TERMIN RMS: POSITI
PANEL
TO DATALO
AL, NEGAT
VE TO
12V PERIPH
IVE
ERALS GGER OR TO OTHER
1012
BATT
INT
EXT
OFF
CHG
ON
Sealed rechargeable batteries are used with the CR510, CR500,
CR10(X), CR7, CR23X, CR5000, and 21XL dataloggers. The nominal rating for the CR510, CR500, CR10(X), CR23X, and CR5000,
batteries is 7.0 Ahrs. The 21XL and CR7's batteries have a nominal rating of 2.5 Ahrs. These batteries should be float-charged
by ac power or a solar panel. The CR23X and CR5000’s batteries can also be float-charged by vehicle power; a DCDC18R
Boost Regulator is required.
PS12
CHG
CHG
CHG
*
LOGAN,
CHARGING
INSTRUCT
ION (AT
2000 )
UTAH
SE
DEF
7
G G
4
8
H
9
L AG
H
5
10
11
L AG
H
6
12
L AG
E3
AG G
G
AG G
G
SW 12V
CTRL
SW 12V
G
G 12V
POWER
IN
SE
DEF
EARTH
CROUN
D
1
G G
1
H
2
3
L AG
H
2
4
5
L AG
H
3
L AG
E3
SERIAL I/O
CR10X
WIRING
PANEL
MADE IN
USA
6
AG G
G G
H
L AG
H
L AG
H
SDM
L AG E3
12V 12V
WIRING
PANEL
NO.
CR10X
MEASUREMENT
AND CONTROL
MODULE
firmware C 1983,
1986, 1995
S/N: X 1012
The PS12LA (exploded view shown)
is a rechargeable power supply for
the CR10(X), CR510, or CR500.
Larger Sealed Rechargeable Batteries
Our BP12 and BP24 battery packs provide more power for systems that have high current drain equipment (e.g., satellite
transmitters). The BP12 and BP24 have nominal ratings of 12
and 24 Ahrs, respectively. These batteries typically use a
CH12R charging regulator, and should be float-charged with ac
power or a solar panel. The current drain of some systems
may require ac power or a deep-cycle RV battery.
The BP24 provides more power
for high current drain systems.
Regulators
A charging regulator must be used to connect rechargeable batteries with a charging source. The MSX10R,
MSX20R, MSX64R, and MSX128R solar panels include a regulator and can be connected directly to an external
rechargeable battery. AC transformers and unregulated solar panels (MSX10, MSX20) must be connected to a
regulator such as the PS12LA, CR5000 base, CR23X base, 21XL base, PS512M, CH12R, CH512R, or CR7 solar
panel input. Our regulators provide built-in temperature compensation to optimize battery performance.
Charging Sources
AC
AC transformers and charging regulators that convert 110 Vac
to 16 Vdc are used to recharge sealed rechargeable batteries. In
areas where the power exceeds 120 Vac, a step-down transformer is required (e.g., VC273 or CR7's ENC 7F enclosure).
Logan, Utah
PN 9591
MADE IN USA
The 9591 wall charger allows you to use ac
power to recharge the rechargeable batteries for
the CR10(X), CR510, and CR500 dataloggers.
Solar Panels
The solar panels charge batteries by converting sunlight into
direct current. The MSX10 and MSX20 are unregulated solar
panels that must be connected to one of the regulators mentioned on the previous page. The MSX10R, MSX20R, MSX64R,
and MSX128R include a regulator allowing them to be directly
connected to a user-supplied external battery. The MSX10
sources sufficient current for many of our systems. Please note
that the MSX10R and MSX20R regulated solar panels have an
2 mA continuous current drain; the MSX64R and MSX128R
draw <3 mA. Solar panel specifications are listed below:
Solar panels are convenient
charging sources for applications
where ac power is not available,
unreliable, or expensive.
MSX10/MSX10R
MSX20/MSX20R
MSX64R
MSX128R
Voltage @ Peak
17.5
17.1
17.5
17.5
Current @ Peak, amps
0.57
1.17
3.66
7.32
Peak Power, Watts
10
20
64
128
NOTE: Specifications assume a 1 kilowatt per square meter illumination and a solar panel temperature of 25°C (77°F).
Individual panels may vary up to 10%. The output panel voltage increases as the panel temperature decreases.
Copyright © 1993, 2002
Campbell Scientific, Inc.
Printed March 2002