Section 4: Batteries and External Power
HOBO Energy Logger User’s Guide
25
•
Battery type
•
Operating environment (e.g., temperature)
The following graph can help you estimate how long batteries will last
(the run time) at different logging intervals and excitation currents with a
warm up time of 30 seconds.
Logging Interval
0.1
1.0
10.0
100.0
1000.0
1
21
41
61
81
101
121
141
161
181
Excitation Current (mA)
B
atte
ry
L
ife
(d
ay
s)
1 Min
5 Min
10 Min
1 Hr
Figure 5: Battery Life
Note:
This graph assumes that standard alkaline batteries and three
FlexSmart modules are being used.
This graph was generated from a spreadsheet that can estimate battery
life for varying parameters. Contact Onset Technical Support for more
information.
Maximizing Battery Life
•
Batteries are inexpensive compared to the cost of a new logger
or a missed logging opportunity. If you suspect that batteries are
damaged or run down, replace them immediately to prevent
leakage or logger malfunction.
•
When launching the logger in HOBOware, do not set a
Sampling Interval
unless you have sensors that support
measurement averaging. Only the following Smart Sensors and
input adapters support measurement averaging:
Section 4: Batteries and External Power
26
HOBO Energy Logger User’s Guide
-
12-bit Temperature S-TMB-M0XX
-
12-bit 4-20 mA Input Adapter (S-CIA-CM14)
-
12-bit Voltage Input Adapter (S-VIA-CM14)
-
Photosynthetically Active Radiation (PAR) S-LIA-M003
-
Silicon Pyranometer (Solar Radiation) S-LIB-M003
Note:
Although some Smart Sensors are intended mainly for
outdoor use (for example, the PAR and Solar Radiation sensors),
the Energy Logger is suitable for indoor use only.
•
If you are using excitation voltage, select the shortest warm up
time needed for the sensor.
•
Verify that the batteries’ “Use Before” date is at least two years
from the current date.
•
Alkaline batteries will lose up to 10% of capacity per year if they
are sitting on a hot shelf. They can lose 50% or more of their
capacity if exposed to heat repeatedly (for example, stored on a
car dashboard). Keeping batteries in the refrigerator can reduce
self-discharge to 1 to 2% per year, but you must prevent
condensation from forming on the batteries.
•
Use new batteries if you expect the deployment to require a
substantial portion of battery life.
Replacing Batteries
Fresh batteries are cheap insurance for extended deployments or high-
draw applications when using an external power source is not feasible.
•
Before replacing batteries, always read out the logger to prevent
data loss.
•
Replace batteries at least once a year to prevent loss of data.
•
Replace batteries more often if you are using sensor excitation.
To replace batteries:
1.
Select the type of batteries you will use and obtain eight fresh,
new batteries of the same type. For more information on
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