Section 4: Batteries and External Power
HOBO Energy Logger User’s Guide
23
Section 4:
Batteries and External
Power
The HOBO Energy Logger requires eight 1.5V AA batteries. The logger
is shipped with eight alkaline batteries, and is also compatible with
enhanced alkaline batteries and lithium batteries (Li/FeS
2
).
An external power source can reduce or eliminate the need for internal
batteries in applications that have readily available AC power, or require
more current and/or longer deployments than the logger's internal
batteries can support. See External Power Sources on page 28.
Selecting batteries
Onset recommends alkaline batteries for most applications because they
are inexpensive, can provide more accurate battery status readings in
HOBOware, and last longer than similar lithium batteries at moderate
temperatures.
However, some applications or environments are better suited to other
types of batteries. Refer to the following table to determine which type of
battery you should use.
Battery type
Considerations for use
Alkaline
These are best for most applications at moderate
temperatures.
Alkaline batteries also work in temperatures ranging
from 40° to 50°C (104° to 122°F) and from -20° to
0°C (-4° to 32°F), but may not perform as well as
lithium batteries at these temperatures.
At temperatures lower than -20°C (-4° F) and higher
than 50°C (122°F), alkaline batteries are not suitable.
Use lithium batteries instead.
Enhanced
alkaline (such as
Energizer
®
E2 or
Duracell
®
Ultra)
Consider these for applications with higher sensor
excitation requirements and moderate temperatures.
These batteries are specifically designed for high-
current use. For low-current applications, however,
they offer little improvement.
Section 4: Batteries and External Power
24
HOBO Energy Logger User’s Guide
Battery type
Considerations for use
Lithium
(Li/FeS
2
)
Lithium batteries last longer than alkaline batteries in
applications with extreme or varying temperatures
(below 0°C/32°F or above 40°C/104°F). They also
outperform alkalines in deployments with high sensor
excitation currents (>100 mA) or long warmup times.
Lithium battery voltage does not vary much until the
batteries are nearly depleted. Because of the
uncertainty in capacity, you may wish to start each
deployment with fresh lithium batteries that you
know are at 100%, rather than rely on old ones.
Important:
Do not use any other type of battery, such as carbon zinc
(“heavy duty”) or rechargeable batteries. These batteries will not perform
well and will not report their battery status accurately in HOBOware.
WARNING:
Fire, Explosion, and Severe Burn Hazard. Do
not mix battery types, either by chemistry or age; batteries
may rupture or explode. When replacing the batteries, read
and follow their disposal instructions; dispose of lithium
batteries according to local regulations. Do not dispose of
batteries in fire. Never attempt to recharge a lithium or
alkaline battery. Do not heat the batteries above 185°F (85°C).
Do not mutilate or rupture the battery housing. Lithium
batteries may explode if the logger is exposed to extreme heat
or conditions that could damage or destroy the battery case.
Do not expose the contents of the battery to water.
Battery Life
Battery life will vary with the following factors:
•
Sensor excitation current and warm up time (most important
factor)
•
Logging interval (and sampling interval, if applicable) selected
•
Number of sensors being used
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